Corina Andronescu

@uni-due.de

Faculty of Chemistry
University Duisburg-Essen



                 

https://researchid.co/corinaandronescu
137

Scopus Publications

4704

Scholar Citations

36

Scholar h-index

100

Scholar i10-index

Scopus Publications

  • Chemical Reaction Pathways during Laser Fragmentation of Metallic Microparticles in Organic Solvents
    Th. Fromme, Rutger Müller, Lars Krenz, Lucie K. Tintrop, Ignacio Sanjuán, Torsten C. Schmidt, K. Tibbetts, Corina Andronescu, S. Reichenberger and Stephan Barcikowski


  • Intrinsically Conductive and Cu-Functionalized Polymer-Composite Membranes as Gas Diffusion Electrodes for CO<inf>2</inf> Electroreduction
    Ignacio Sanjuán, Vaibhav Kumbhar, Oleg Prymak, Mathias Ulbricht, Corina Andronescu, and Lukas Fischer
    Wiley
    AbstractWe introduced a new class of gas diffusion electrodes (GDEs) with adjustable pore morphology. We fabricated intrinsically conductive polymer‐composite membranes containing carbon filler, enabling a pore structure variation through film casting cum phase separation protocols. We further selectively functionalized specific pore regions of the membranes with Cu by a NaBH4‐facilitated coating strategy. The as‐obtained GDEs can facilitate the electrochemical CO2 reduction reaction (CO2RR) at Cu active sites that are presented inside a defined and electrically conductive pore system. When employing them as free‐standing cathodes in a CO2 flow electrolyzer, we achieved &gt;70 % Faradaic efficiencies for CO2RR products at up to 200 mA/cm2. We further demonstrated that deposition of a dense Cu layer on top of the membrane leads to obstruction of the underlying pore openings, inhibiting an excessive wetting of the pore pathways that transport gaseous CO2. However, the presentation of Cu inside the pore system of our novel membrane electrodes increased the C2H4/CO selectivity by a factor of up to 3 compared to Cu presented in the dense layer on top of the membrane. Additionally, we found that gaseous CO2 could still access Cu in macropores after wetting with electrolyte, while CO2RR was completely suppressed in wetted nm‐scale pores.

  • Deciphering the Electrochemical Activity and Selectivity of Earth-Abundant Transition Metal-Based Catalysts for the Alcohol Electrooxidation—Current Status
    Michael Braun and Corina Andronescu
    Wiley
    AbstractSince alternative anode reactions such as the electrochemical alcohol oxidation reaction (AOR) are becoming increasingly important for water electrolysis in the course of a sustainable defossilization and electrification of the energy and chemical industry, this paper reviews the progress in understanding the electrocatalytic activity and selectivity of non‐noble metal‐based (non‐NMB) catalysts regarding AOR and especially, the glycerol oxidation reaction (GOR). Starting from Ni‐based catalysts, the review aims to consolidate the current state of knowledge for improving electrocatalytic activity based on mechanistic models and to transfer it to Co‐ and Cu‐based materials. Several main influences on the catalytic activity can be identified via the involvement of metal ions (metal redox reactions) or oxygen species (oxygen redox reactions), which lead to the importance of M─O motifs for the electrocatalytically active ensemble on the surface of an electrically conductive non‐NMB catalyst. In addition to the electrocatalytic activity, this work delves into possibilities for influencing the selectivity during AOR, which include the catalyst itself, electrode potential, or the pH value of the electrolyte. Furthermore, the chemical structure of the alcohol proves to be crucial, especially when oxidizing vicinal alcohols, because differentiating products from oxidative (pseudo)glycol cleavage and hydrogen atom transfer can complicate understanding selectivity influences.

  • Determining materials for energy conversion across scales: The alkaline oxygen evolution reaction
    Philipp Gerschel, Steven Angel, Mohaned Hammad, André Olean‐Oliveira, Blaž Toplak, Vimanshu Chanda, Ricardo Martínez‐Hincapié, Sebastian Sanden, Ali Raza Khan, Da Xing,et al.
    Wiley
    AbstractDespite considerable efforts to develop electrolyzers for energy conversion, progress has been hindered during the implementation stage by different catalyst development requirements in academic and industrial research. Herein, a coherent workflow for the efficient transition of electrocatalysts from basic research to application readiness for the alkaline oxygen evolution reaction is proposed. To demonstrate this research approach, La0.8Sr0.2CoO3 is selected as a catalyst, and its electrocatalytic performance is compared with that of the benchmark material NiFe2O4. The La0.8Sr0.2CoO3 catalyst with the desired dispersity is successfully synthesized by scalable spray‐flame synthesis. Subsequently, inks are formulated using different binders (Nafion®, Naf; Sustainion®, Sus), and nickel substrates are spray coated, ensuring a homogeneous catalyst distribution. Extensive electrochemical evaluations, including several scale‐bridging techniques, highlight the efficiency of the La0.8Sr0.2CoO3 catalyst. Experiments using the scanning droplet cell (SDC) indicate good lateral homogeneity for La0.8Sr0.2CoO3 electrodes and NiFe2O4‐Sus, while the NiFe2O4‐Naf film suffers from delamination. Among the various half‐cell techniques, SDC proves to be a valuable tool to quickly check whether a catalyst layer is suitable for full‐cell‐level testing and will be used for the fast‐tracking of catalysts in the future. Complementary compression and flow cell experiments provide valuable information on the electrodes' behavior upon exposure to chemical and mechanical stress. Finally, parameters and conditions simulating industrial settings are applied using a zero‐gap cell. Findings from various research fields across different scales obtained based on the developed coherent workflow contribute to a better understanding of the electrocatalytic system at the early stages of development and provide important insights for the evaluation of novel materials that are to be used in large‐scale industrial applications.

  • Reproducible Superinsulation Materials: Organosilica-Based Hybrid Aerogels with Flexibility Control
    Marvin Geyer, Felix Leven, Johannes Limberg, Corina Andronescu, and Rainer Ostermann
    MDPI AG
    In this study, we report highly crosslinked hybrid aerogels with an organic backbone based on vinylmethyldimethoxysilane (VMDMS) with tuneable properties. For an improved and highly reproducible synthesis, a prepolymer based on 2,4,6,8-tetramethyl-2,4,6,8-tetravinylcyclotetrasiloxane (D4V4) and VMDMS as monomers was prepared and purified. Di-tert-butylperoxide (DTBP) concentrations of 1 mol% initiate the radical polymerization of the mentioned monomers to achieve high yields of polymers. After purification, the obtained viscous polyorganosilane precursor could be reproducibly crosslinked with dimethyldimethoxysilane (DMDMS) or methyltrimethoxysilane (MTMS) to form gels in benzylic alcohol (BzOH), water (H2O) and tetramethylammonium hydroxide (TMAOH). Whereas freeze-drying these silica-based hybrid aerogels led to high thermal conductivity (&gt;20 mW m−1K−1) and very fragile materials, useful aerogels were obtained via solvent exchange and supercritical drying with CO2. The DMDMS-based aerogels exhibit enhanced compressibility (31% at 7 kPa) and low thermal conductivity (16.5 mW m−1K−1) with densities around (0.111 g cm−3). The use of MTMS results in aerogels with lower compressibility (21% at 7 kPa) and higher density (0.124 g cm−3) but excellent insulating properties (14.8 mW m−1K−1).

  • Gas Diffusion Electrodes for Electrocatalytic Oxidation of Gaseous Ammonia: Stepping Over the Nitrogen Energy Canyon
    Ieva A. Cechanaviciute, Bhawana Kumari, Lars M. Alfes, Corina Andronescu, and Wolfgang Schuhmann
    Wiley
    AbstractAs ammonia continues to gain more and more interest as a promising hydrogen carrier compound, so does the electrochemical ammonia oxidation reaction (AmOR). To avoid the liberation of H2 in a reverse Haber–Bosch reaction under release of the energetically more favorable N2, we propose the oxidation of ammonia to value‐added nitrite (NO2−), which is usually obtained during the Ostwald process. We investigated the anodic oxidation of gaseous ammonia directly supplied to a gas diffusion electrode (GDE) using a variety of compositionally different multi‐metal catalysts coated on Ni foam under the simultaneous formation of H2 at the cathode. This will double the amount of H2 per ammonia molecule while applying a lower overpotential than that required for water electrolysis (1.4–1.8 V vs. RHE at 50 mA ⋅ cm−2). A selectivity study demonstrated that some of the catalyst compositions were able to produce significant amounts of NO2−, and further investigations using the most promising catalyst composition Nif_AlCoCrCuFe integrated within a GDE demonstrated up to 88 % Faradaic efficiency for NO2− at the anode coupled to close to 100 % Faradaic efficiency for the cathodic H2 production.

  • Design of conducting polymer/metal-based nanocomposites as electrocatalysts for electrochemical energy conversion
    Alejandro E. Pérez Mendoza, Corina Andronescu, and André Olean-Oliveira
    Elsevier BV

  • Bi site doped Ferroelectric BiFe<inf>0.95</inf>Mn<inf>0.05</inf>O<inf>3</inf> Nanoparticles for Hydrogen Evolution Reaction
    Astita Dubey, Ignacio Sanjuán, Corina Andronescu, and Doru C. Lupascu
    Wiley
    AbstractThe investigation delves into the functionality exhibited by ferroelectric BiFe0.95Mn0.05O3 (BFM) nanoparticles (NPs) concerning the hydrogen evolution reaction (HER). The electrocatalytic activity of BFM NPs undergoes a transformative shift as a consequence of mono‐, di‐, and tri‐valent cation substitution. Notably, the strategic engineering of doping at the Bi site within BFM NPs yields a remarkable outcome, namely the conspicuous reduction of the kinetic overpotential prerequisite for HER. This diminished overpotential in doped BFM NPs arises from the confluence of multifarious factors: diminished charge transfer resistance, augmented specific surface area, a discernible distribution of pore sizes ranging from narrow to broad, particles endowed with a shape boasting abundant active facets, and the integration of dopants as novel active sites on the surface. Furthermore, the presence of surface defects, oxygen vacancies, and amplified microstrain within doped BFM NPs contributes to the reduction in overpotential.

  • Polyacrylonitrile-based porous polymer spheres and their conversion to N-doped carbon materials for adsorption and electrocatalysis
    Zhuo Gao, Ignacio Sanjuán, Ulrich Hagemann, Alexandra S. M. Wittmar, Corina Andronescu, and Mathias Ulbricht
    Wiley
    AbstractBecause of their tunable porosity and specific surface area, porous materials are of high interest for the purification of wastewater by adsorption as well as in electrocatalysis, where, in particular, developing metal‐free carbon‐based catalysts for the oxygen reduction reaction (ORR) is researched. The carbon spheres presented here can meet these two requirements simultaneously. Porous polyacrylonitrile (PAN) spheres were firstly prepared by droplet shaping cum nonsolvent induced phase separation. Then, they were converted to nitrogen‐doped carbon spheres by two‐step carbonization via preoxidation and pyrolysis. During the pyrolysis step, carbon dioxide was used to reopen the pores of the materials that had been blocked after the preoxidation step. By this way, specific surface area values of carbon spheres of more than 1000 m2/g could be obtained. Best performing carbon materials (C#3) showed high adsorption capacity (e.g., 296 mg/g for methyl orange at solute equilibrium concentration of 24 mg/L in water). The XPS analysis revealed that only quaternary (N‐Q) and pyridinic (N‐6) nitrogen sites were found in these carbon spheres. The best ORR performance was found also for C#3 carbon spheres, with a potential of 0.81 V versus reversible hydrogen electrode (RHE) at −1 mA/cm2 and electron transfer number of 3.5 at 0.6–0.8 V versus RHE, as determined by rotating disk or rotating ring disk electrode tests. In conclusion, all results confirm that these PAN‐derived carbon spheres are potentially valuable materials for both wastewater treatment by adsorption and electrocatalytic oxygen reduction.

  • Tunable Syngas Formation at Industrially Relevant Current Densities via CO<inf>2</inf> Electroreduction and Hydrogen Evolution over Ni and Fe-derived Catalysts obtained via One-Step Pyrolysis of Polybenzoxazine Based Composites
    Ignacio Sanjuán, Vaibhav Kumbhar, Vimanshu Chanda, Raíssa R. L. Machado, Bright N. Jaato, Michael Braun, Muhammad A. A. Mahbub, Georg Bendt, Ulrich Hagemann, Markus Heidelmann,et al.
    Wiley
    AbstractSimultaneous electroreduction of CO2 and H2O to syngas can provide a sustainable feed for established processes used to synthesize carbon‐based chemicals. The synthesis of MOx/M‐N‐Cs (M = Ni, Fe) electrocatalysts reported via one‐step pyrolysis that shows increased performance during syngas electrosynthesis at high current densities with adaptable H2/CO ratios, e.g., for the Fischer–Tropsch process. When embedded in gas diffusion electrodes (GDEs) with optimized hydrophobicity, the NiOx/Ni‐N‐C catalyst produces syngas (H2/CO = 0.67) at −200 mA cm−2 while for the FeOx/Fe‐N‐C syngas production occurs at ≈−150 mA cm−2. By tuning the electrocatalyst's microenvironment, stable operation for &gt;3 h at −200 mA cm−2 is achieved with the NiOx/Ni‐N‐C GDE. Post‐electrolysis characterization revealed that the restructuring of the catalyst via reduction of NiOx to metallic Ni NPs still enables stable operation of the electrode at −200 mA cm−2, when embedded in an optimized microenvironment. The ionomer and additives used in the catalyst layer are important for the observed stable operation. Operando Raman measurements confirm the presence of NiOx during CO formation and indicate weak adsorption of CO on the catalyst surface.

  • From Small-Area Observations to Insight: Surface-Feature-Extrapolation of Anodes for Alkaline Oxygen Evolution Reaction
    Adarsh Jain, Vineetha Vinayakumar, André Olean‐Oliveira, Christian Marcks, Mohit Chatwani, Anna K. Mechler, Corina Andronescu, and Doris Segets
    Wiley
    AbstractIn this study, we developed a statistical framework, named multistage data quantification (MSDQ), to evaluate representative surface characteristics such as surface roughness, surface area, and homogeneity score of cobalt oxide‐based anodes, and contributing to a deeper insight into the quality of the anode surface. Atomic force microscopy (AFM) was employed to capture the surface morphology of two anodes that have a comparable loading of cobalt oxide but exhibit distinct morphological features. Application of MSDQ exposed notable disparities in surface characteristics across these anodes, underlining the critical importance of MSDQ in precise surface characterization. Specifically, surface roughness, surface area and homogeneity score effectively elucidated the disparities in electrocatalytic activity for the oxygen evolution reaction (OER), as quantified through scanning droplet cell (SDC) measurements. By conducting a systematic comparative analysis, the respective contributions of the extrinsic surface characteristics of the anodes to the intrinsic electrocatalytic material property could be differentiated and quantified. Applications of our findings range from benchmarking of anodes to optimization of anode manufacturing processes.

  • Exploring the (Dis)-Similarities of Half-Cell and Full Cell Zero-Gap Electrolyzers for the CO<inf>2</inf> Electroreduction
    Vimanshu Chanda, Dennis Blaudszun, Lucas Hoof, Ignacio Sanjuán, Kevinjeorjios Pellumbi, Kai junge Puring, Corina Andronescu, and Ulf‐Peter Apfel
    Wiley
    AbstractCarbon dioxide electroreduction (CO2R) is a promising technology for mitigating industrial CO2 emissions and generating valuable chemicals using renewable energy sources. Recent advances have centered on fine‐tuning catalyst materials and their micro‐environments, stimulating interest within the CO2R community. However, testing novel catalyst materials often occurs under conditions different from those relevant to industrial applications. In this study, we explore the transferability of CO2R results obtained using Ag‐based gas diffusion electrode (GDEs) in an easy to fabricate, assemble and test zero‐gap half‐cell (ZGHC) to a zero‐gap electrolyzer (ZGE). Our investigation reveals that the transferability of results is not only influenced by the reactor design, but also partially dependent on the type of additive used in the catalyst layer of the GDE. Moreover, we show that the humidity of the CO2 is a crucial operational parameter that not only impacts the selectivity of the electrode but also influences its stability during testing in the ZGHC. These findings highlight the importance of comprehensively considering operational conditions as well as reactor designs when comparing results between the ZGHC and ZGE, presenting finally a pathway on how to minimize such differences.

  • Surface Reconstruction Induced by Preconditioning in Different Electrolytes Impacts Electrooxidation of Solketal on Multi-Metal-Based Catalysts
    Jian Zhang, Bhawana Kumari, Thomas Quast, Steffen Cychy, Ignacio Sanjuán, Martin Muhler, Wolfgang Schuhmann, and Corina Andronescu
    Wiley
    AbstractThe electrocatalytic oxidation of solketal (SOR) as the anodic reaction can be used to enhance hydrogen production efficiency due to its lower overpotential compared to the oxygen evolution reaction (OER). Additionally, solketal oxidation yields besides formate also high‐value C3 products, providing an advantage over the typical alternative reaction for OER, glycerol oxidation. The multi‐metal CoNiFeCu (1:1:1:0.5) catalyst is employed as electrocatalyst for SOR and different activation procedures are explored. The pre‐conditioning of the catalyst in the presence of solketal supports a current density of 10 mA cm−2 to be recorded at only 1.405 ± 1 mV versus reversible hydrogen electrode (vs. RHE) during SOR, while promoting glyceric acid synthesis with 40% faradaic efficiency. Operando attenuated total reflection Fourier‐transform infrared spectroscopy (ATR‐FTIR) confirms that the activation of the catalyst contributes to an increased formation of products. However, most importantly, through utilizing the single‐particle‐on‐the‐nanoelectrode with identical‐location transmission electron microscope (IL‐TEM), it is unveiled that solketal suppresses Cu leaching and oxyhydroxide formation. Moreover, the structural transformations are correlated with the increased activity toward SOR.

  • Accelerating CO<inf>2</inf> electrochemical conversion towards industrial implementation
    Doris Segets, Corina Andronescu, and Ulf-Peter Apfel
    Springer Science and Business Media LLC

  • Forschungstransfer: Elektrochemische CO2-Reduktion
    Daniel Siegmund, Corina Andronescu, Christof Schulz, Harry Hoster, Doris Segets, and Ulf‐Peter Apfel
    Wiley
    AbstractAkademische Forschung und industrielle Anwendung – wie die Zusammenarbeit zwischen Industrie und Akademia zu optimieren ist, zeigt ein Blick aus der technischen Elektrochemie auf deren Anwendung in der Industrie. Wichtig ist dabei eine klare Kommunikation auf beiden Seiten.

  • A CuO<inf>x</inf>/Cu/C electrocatalyst-based gas diffusion electrode for the electroreduction of CO<inf>2</inf> with high selectivity to C<inf>2</inf>H<inf>4</inf>
    Vimanshu Chanda, João R. C. Junqueira, Nivedita Sikdar, Ignacio Sanjuán, Michael Braun, Stefan Dieckhöfer, Sabine Seisel, and Corina Andronescu
    Wiley
    AbstractElectrochemical conversion of CO2 (CO2RR) has received significant attention since it could provide pathways for renewable energy storage to energy‐dense chemicals and synthetic fuels. We developed a novel CuOx/Cu/C type electrocatalyst via pyrolysis, which we used to convert CO2 at industrially relevantly current densities using gas diffusion electrodes. The influence of the pyrolysis conditions on the electrocatalytic CO2RR activity and selectivity was evaluated. Optimization of the electrode structure to mitigate electrowetting was done by mixing the catalyst with polytetrafluoroethylene (PTFE). We found that mixing the most active catalyst with PTFE in a mass ratio of 1 to 0.25 substantially increased the formation of C2H4 displaying 41% Faradaic efficiency (FE) at –240 mA cm–2. Prolonged CO2RR at different current densities shows that the electrode containing 25 wt.% PTFE in the catalyst layer display FEC2H4 &gt; 40% at –280 mA cm–2 for 2 h.

  • Acidic Hydrogen Evolution Electrocatalysis at High-Entropy Alloys Correlates with its Composition-Dependent Potential of Zero Charge
    Moonjoo Kim, Emmanuel Batsa Tetteh, Olga A. Krysiak, Alan Savan, Bin Xiao, Tobias Horst Piotrowiak, Corina Andronescu, Alfred Ludwig, Taek Dong Chung, and Wolfgang Schuhmann
    Wiley
    AbstractThe vast possibilities in the elemental combinations of high‐entropy alloys (HEAs) make it essential to discover activity descriptors for establishing rational electrocatalyst design principles. Despite the increasing attention on the potential of zero charge (PZC) of hydrogen evolution reaction (HER) electrocatalyst, neither the PZC of HEAs nor the impact of the PZC on the HER activity at HEAs has been described. Here, we use scanning electrochemical cell microscopy (SECCM) to determine the PZC and the HER activities of various elemental compositions of a Pt−Pd−Ru−Ir−Ag thin‐film HEA materials library (HEA‐ML) with high statistical reliability. Interestingly, the PZC of Pt−Pd−Ru−Ir−Ag is linearly correlated with its composition‐weighted average work function. The HER current density in acidic media positively correlates with the PZC, which can be explained by the preconcentration of H+ in the electrical double layer at potentials negative of the PZC.

  • Elucidation of alkaline electrolyte-surface interaction in SECCM using a pH-independent redox probe
    Swapnil Varhade, Gabriel Meloni, Emmanuel Batsa Tetteh, Monjoo Kim, Simon Schumacher, Thomas Quast, Corina Andronescu, Patrick Unwin, and Wolfgang Schuhmann
    Elsevier BV

  • Preparation of N-doped carbon materials from cellulose:chitosan blends and their potential application in electrocatalytic oxygen reduction
    Alexandra S. M. Wittmar, Marcus Ropertz, Michael Braun, Ulrich Hagemann, Corina Andronescu, and Mathias Ulbricht
    Springer Science and Business Media LLC
    AbstractCarbon-based electrocatalysts for oxygen reduction reaction (ORR) are prepared by a direct pathway including a two-step thermal treatment process applied to porous spheres of natural biopolymer blends. Cellulose blends with chitosan are first thermally treated at moderate temperatures (e.g., 200 °C), then pyrolyzed at elevated temperature (800–1000 °C), both steps under a constant nitrogen flow. By blending of cellulose with chitosan, the nitrogen content in the final carbon-based catalyst can be considerably increased. The influence of the composition of the precursor biopolymer blend on the ORR electrocatalytic activity is analyzed in correlation with the elemental composition and other structural features of the catalyst. The polymer blend containing cellulose:chitosan = 75:25, thermally treated 1 h at 200 °C and pyrolyzed 1 h at 800 °C under nitrogen atmosphere, shows the highest electrocatalytic ORR activity. This is attributed to an increased surface area combined with relatively high nitrogen content and a higher pyridinic/pyrrolic species ratio.

  • From waste to value – Glycerol electrooxidation for energy conversion and chemical production
    Michael Braun, Cássia S. Santana, Amanda C. Garcia, and Corina Andronescu
    Elsevier BV

  • Operando Scanning Electrochemical Probe Microscopy during Electrocatalysis
    Carla Santana Santos, Bright Nsolebna Jaato, Ignacio Sanjuán, Wolfgang Schuhmann, and Corina Andronescu
    American Chemical Society (ACS)
    Scanning electrochemical probe microscopy (SEPM) techniques can disclose the local electrochemical reactivity of interfaces in single-entity and sub-entity studies. Operando SEPM measurements consist of using a SEPM tip to investigate the performance of electrocatalysts, while the reactivity of the interface is simultaneously modulated. This powerful combination can correlate electrochemical activity with changes in surface properties, e.g., topography and structure, as well as provide insight into reaction mechanisms. The focus of this review is to reveal the recent progress in local SEPM measurements of the catalytic activity of a surface toward the reduction and evolution of O2 and H2 and electrochemical conversion of CO2. The capabilities of SEPMs are showcased, and the possibility of coupling other techniques to SEPMs is presented. Emphasis is given to scanning electrochemical microscopy (SECM), scanning ion conductance microscopy (SICM), electrochemical scanning tunneling microscopy (EC-STM), and scanning electrochemical cell microscopy (SECCM).

  • Electrooxidation of the Glycerol Derivative Solketal over Cu−Co Hydroxycarbonates to Enable the Synthesis of Glyceric Acid
    Bhawana Kumari, Michael Braun, Steffen Cychy, Ignacio Sanjuán, Gereon Behrendt, Malte Behrens, Martin Muhler, and Corina Andronescu
    Wiley

  • Cobalt nickel boride as electrocatalyst for the oxidation of alcohols in alkaline media
    Michael Braun, Mohit Chatwani, Piyush Kumar, Yun Hao, Ignacio Sanjuán, Ariadni-Aikaterini Apostoleri, Ann Cathrin Brix, Dulce M Morales, Ulrich Hagemann, Markus Heidelmann,et al.
    IOP Publishing
    Abstract A mixed Co and Ni boride precursor was synthesized via chemical reduction and subsequently annealed at 400 or 500 °C with or without prior addition of the monomer benzoxazine (BO). The resulting mixed CoNiB materials were investigated as electrocatalysts for three alcohol oxidation reactions (AOR) in alkaline electrolyte: the oxidation of glycerol (GOR), ethylene glycol (EGOR) and ethanol (EOR). Comparison of the rotating disk electrode (RDE) cyclic voltammograms for the different catalysts revealed that CoNiB annealed at 500 °C without the addition of BO exhibited the lowest overpotentials in AORs at 10 mA cm−2, promoting GOR at 224 ± 6 mV lower potential compared to OER. When pyrolysis was conducted at 400 °C, the BO-containing catalyst showed a significant increase in the electrocatalytic activity for the AORs compared to the CoNiB catalyst only. The product selectivity on the different catalysts was investigated in a batch-type reactor with flow recirculation revealing formate as the main oxidation product during GOR and EGOR with faradaic efficiencies (FE) in a range of 60%–80%, while acetate was obtained during EOR (FE ∼ 85%–90%). The electrode potential, electrolyte composition and the type of ionomer were explored with respect to their influence on the GOR selectivity. The use of different ionomers resulted in significant differences in the activity trends between RDE and the batch-type reactor with flow recirculation measurements, indicating a strong influence of the two different substrates used, namely glassy carbon and carbon paper on the catalyst formation and thus on the recorded electrochemical activity.

  • Spray-Flame Synthesis of LaFe<inf>x</inf>Co<inf>1- x</inf>O<inf>3</inf>(x = 0.2, 0.3) Perovskite Nanoparticles for Oxygen Evolution Reaction in Water Splitting: Effect of Precursor Chemistry (Acetates and Nitrates)
    Steven Angel, Michael Braun, Baris Alkan, Joachim Landers, Soma Salamon, Heiko Wende, Corina Andronescu, Christof Schulz, and Hartmut Wiggers
    American Chemical Society (ACS)
    The product properties of mixed oxide nanoparticles generated via spray-flame synthesis depend on an intricate interplay of solvent and precursor chemistries in the processed solution. The effect of two different sets of metal precursors, acetates and nitrates, dissolved in a mixture of ethanol (35 Vol.%) and 2-ethylhexanoic acid (2-EHA, 65 Vol.%) was investigated for the synthesis of LaFexCo1-xO3 (x = 0.2, 0.3) perovskites. Regardless of the set of precursors, similar particle-size distributions (dp = 8-11 nm) were obtained and a few particles with sizes above 20 nm were identified with transmission electron microscopy (TEM) measurements. Using acetates as precursors, inhomogeneous La, Fe, and Co elemental distributions were obtained for all particle sizes according to energy dispersive X-ray (EDX) mappings, connected to the formation of multiple secondary phases such as oxygen-deficient La3(FexCo1-x)3O8 brownmillerite or La4(FexCo1-x)3O10 Ruddlesden-Popper (RP) structures besides the main trigonal perovskite phase. For samples synthesized from nitrates, inhomogeneous elemental distributions were observed for large particles only where La and Fe enrichment occurred in combination with the formation of a secondary La2(FexCo1-x)O4 RP phase. Such variations can be attributed to reactions in the solution prior to injection in the flame as well as precursor-dependent variations in in-flame reactions. Therefore, the precursor solutions were analyzed by temperature-dependent attenuated total reflection Fourier-transform infrared (ATR-FTIR) measurements. The acetate-based precursor solutions indicated the partial conversion of, mainly La and Fe, acetates to metal 2-ethylhexanoates. In the nitrate-based solutions, esterification of ethanol and 2-EHA played the most important role. The synthesized nanoparticle samples were characterized by BET (Brunauer, Emmett, Teller), FTIR, Mössbauer, and X-ray photoelectron spectroscopy (XPS). All samples were tested as oxygen evolution reaction (OER) catalysts, and similar electrocatalytic activities were recorded when evaluating the potential required to reach 10 mA/cm2 current density (∼1.61 V vs reversible hydrogen electrode (RHE)).

  • Microscale Combinatorial Libraries for the Discovery of High-Entropy Materials
    Lars Banko, Emmanuel Batsa Tetteh, Aleksander Kostka, Tobias Horst Piotrowiak, Olga Anna Krysiak, Ulrich Hagemann, Corina Andronescu, Wolfgang Schuhmann, and Alfred Ludwig
    Wiley
    Polyelemental material systems, specifically high‐entropy alloys, promise unprecedented properties. Due to almost unlimited combinatorial possibilities, their exploration and exploitation is hard. This challenge is addressed by co‐sputtering combined with shadow masking to produce a multitude of microscale combinatorial libraries in one deposition process. These thin‐film composition spreads on the microscale cover unprecedented compositional ranges of high‐entropy alloy systems and enable high‐throughput characterization of thousands of compositions for electrocatalytic energy conversion reactions using nanoscale scanning electrochemical cell microscopy. The exemplary exploration of the composition space of two high‐entropy alloy systems provides electrocatalytic activity maps for hydrogen evolution and oxygen evolution as well as oxygen reduction reactions. Activity optima in the system Ru–Rh–Pd–Ir–Pt are identified, and active noble‐metal lean compositions in the system Co–Ni–Mo–Pd–Pt are discovered. This illustrates that the proposed microlibraries are a holistic discovery platform to master the multidimensionality challenge of polyelemental systems.

RECENT SCHOLAR PUBLICATIONS

  • Unlocking High-Performance Ni-Co-O Anodes for Oxygen Evolution: A Coherent Workflow from Catalyst Powder to Plasma-Enhanced Electrodes
    V Vinayakumar, T Wagner, C Marcks, J Johny, G Wartner, MF Tesch, ...
    247th ECS Meeting (May 18-22, 2025) 2025

  • Chemical Reaction Pathways during Laser Fragmentation of Metallic Microparticles in Organic Solvents
    T Fromme, R Müller, L Krenz, LK Tintrop, I Sanjun, TC Schmidt, ...
    The Journal of Physical Chemistry C 2025

  • Intrinsically Conductive and Cu‐Functionalized Polymer‐Composite Membranes as Gas Diffusion Electrodes for CO2 Electroreduction
    I Sanjun, V Kumbhar, O Prymak, M Ulbricht, C Andronescu, L Fischer
    ChemSusChem 18 (2), e202401228 2025

  • Ni-Co-O anodes for the alkaline oxygen evolution reaction: Multistage electrode optimization and plasma-assisted activity enhancement enabled by a coherent workflow
    V Vinayakumar, T Wagner, C Marcks, J Johny, G Wartner, MF Tesch, ...
     2024

  • Determining materials for energy conversion across scales: The alkaline oxygen evolution reaction
    P Gerschel, S Angel, M Hammad, A Olean‐Oliveira, B Toplak, V Chanda, ...
    Carbon Energy 6 (12), e608 2024

  • Investigating Anode Structural Characteristics with Multistage Data Quantification: Influence of Extrinsic Properties of Anodes for Oxidation Evolution Reaction in Alkaline
    A Jain, V Vinayakumar, A Olean-Oliveira, C Marcks, M Chatwani, ...
    Electrochemical Society Meeting Abstracts prime2024, 2197-2197 2024

  • Reproducible Superinsulation Materials: Organosilica-Based Hybrid Aerogels with Flexibility Control
    M Geyer, F Leven, J Limberg, C Andronescu, R Ostermann
    Gels 10 (11), 692 2024

  • Gasdiffusionselektroden fr die Elektrokatalytische Oxidation von Gasfrmigem Ammoniak: Das berqueren des Thermodynamischen Tals der Stickstoffdreifachbindung
    IA Cechanaviciute, B Kumari, LM Alfes, C Andronescu, W Schuhmann
    Angewandte Chemie 136 (41), e202404348 2024

  • Gas diffusion electrodes for electrocatalytic oxidation of gaseous ammonia: stepping over the nitrogen energy canyon
    IA Cechanaviciute, B Kumari, LM Alfes, C Andronescu, W Schuhmann
    Angewandte Chemie International Edition 63 (41), e202404348 2024

  • Impact of the Gas Atmosphere on the Local OER Activity of a Two-Phase Ni2B/Ni3B Ingot: SECCM Study
    L Madayan Banatheth, AE Perez Mendoza, U Burkhardt, I Antonyshyn, ...
    Proceedings of MATSUS Fall 2024 Conference (MATSUSFall24) 2024

  • Alcohol electrooxidation over non-noble multi-metal electrocatalysts: strategies to increase the catalyst activity and control the reaction selectivity
    C Andronescu
    Proceedings of MATSUS Fall 2024 Conference (MATSUSFall24) 2024

  • Front Cover: Bi site doped Ferroelectric BiFe0.95Mn0.05O3 Nanoparticles for Hydrogen Evolution Reaction (ChemCatChem 12/2024)
    A Dubey, I Sanjun, C Andronescu, DC Lupascu
    ChemCatChem 16 (12), e202481201 2024

  • Bi site doped Ferroelectric BiFe0.95Mn0.05O3 Nanoparticles for Hydrogen Evolution Reaction
    A Dubey, I Sanjun, C Andronescu, DC Lupascu
    ChemCatChem 16 (12), e202400130 2024

  • Polyacrylonitrile‐based porous polymer spheres and their conversion to N‐doped carbon materials for adsorption and electrocatalysis
    Z Gao, I Sanjun, U Hagemann, ASM Wittmar, C Andronescu, M Ulbricht
    Journal of Applied Polymer Science 141 (22), e55438 2024

  • Design of Conducting Polymer/Metal-based Nanocomposites as Electrocatalysts for Electrochemical Energy Conversion
    AEP Mendoza, C Andronescu, A Olean-Oliveira
    Synthetic Metals, 117662 2024

  • Tunable Syngas Formation at Industrially Relevant Current Densities via CO2 Electroreduction and Hydrogen Evolution over Ni and Fe‐derived Catalysts obtained
    I Sanjun, V Kumbhar, V Chanda, RRL Machado, BN Jaato, M Braun, ...
    Small 20 (23), 2305958 2024

  • From Small‐Area Observations to Insight: Surface‐Feature‐Extrapolation of Anodes for Alkaline Oxygen Evolution Reaction
    A Jain, V Vinayakumar, A Olean‐Oliveira, C Marcks, M Chatwani, ...
    ChemCatChem 16 (5), e202301461 2024

  • Exploring the (Dis)‐Similarities of Half‐Cell and Full Cell Zero‐Gap Electrolyzers for the CO2 Electroreduction
    V Chanda, D Blaudszun, L Hoof, I Sanjun, K Pellumbi, K Junge Puring, ...
    ChemElectroChem 11 (5), e202300715 2024

  • Surface Reconstruction Induced by Preconditioning in Different Electrolytes Impacts Electrooxidation of Solketal on Multi‐Metal‐Based Catalysts
    J Zhang, B Kumari, T Quast, S Cychy, I Sanjun, M Muhler, W Schuhmann, ...
    Advanced Functional Materials, 2419911 2024

  • Accelerating CO2 electrochemical conversion towards industrial implementation
    D Segets, C Andronescu, UP Apfel
    nature communications 14 (1), 7950 2023

MOST CITED SCHOLAR PUBLICATIONS

  • Electrocatalysis as the nexus for sustainable renewable energy: the gordian knot of activity, stability, and selectivity
    J Masa, C Andronescu, W Schuhmann
    Angewandte Chemie International Edition 59 (36), 15298-15312 2020
    Citations: 209

  • Sericin covalent immobilization onto cellulose acetate membrane for biomedical applications
    SI Voicu, RM Condruz, V Mitran, A Cimpean, F Miculescu, C Andronescu, ...
    ACS Sustainable Chemistry & Engineering 4 (3), 1765-1774 2016
    Citations: 178

  • Cascade reactions in nanozymes: Spatially separated active sites inside Ag-Core–Porous-Cu-shell nanoparticles for multistep carbon dioxide reduction to higher organic molecules
    PB O’Mara, P Wilde, TM Benedetti, C Andronescu, S Cheong, JJ Gooding, ...
    Journal of the American Chemical Society 141 (36), 14093-14097 2019
    Citations: 176

  • Low overpotential water splitting using cobalt–cobalt phosphide nanoparticles supported on nickel foam
    J Masa, S Barwe, C Andronescu, I Sinev, A Ruff, K Jayaramulu, ...
    ACS Energy Letters 1 (6), 1192-1198 2016
    Citations: 161

  • Influence of the Fe:Ni Ratio and Reaction Temperature on the Efficiency of (FexNi1–x)9S8 Electrocatalysts Applied in the Hydrogen Evolution Reaction
    S Piontek, C Andronescu, A Zaichenko, B Konkena, K Puring, B Marler, ...
    ACS Catalysis 8 (2), 987-966 2018
    Citations: 160

  • Powder catalyst fixation for post‐electrolysis structural characterization of NiFe layered double hydroxide based oxygen evolution reaction electrocatalysts
    C Andronescu, S Barwe, E Ventosa, J Masa, E Vasile, B Konkena, ...
    Angewandte Chemie International Edition 56 (37), 11258-11262 2017
    Citations: 154

  • MOFs for electrocatalysis: from serendipity to design strategies
    HB Aiyappa, J Masa, C Andronescu, M Muhler, RA Fischer, ...
    Small Methods 3 (8), 1800415 2019
    Citations: 128

  • Local surface structure and composition control the hydrogen evolution reaction on iron nickel sulfides
    C Bentley, C Andronescu, M Smialkowski, M Kang, T Tarnev, B Marler, ...
    Angewandte Chemie 2018
    Citations: 127

  • Oxygen evolution electrocatalysis of a single MOF‐derived composite nanoparticle on the tip of a nanoelectrode
    HB Aiyappa, P Wilde, T Quast, J Masa, C Andronescu, YT Chen, ...
    Angewandte Chemie International Edition 58 (26), 8927-8931 2019
    Citations: 110

  • B‐Cu‐Zn Gas Diffusion Electrodes for CO2 Electroreduction to C2+ Products at High Current Densities
    Y Song, JRC Junqueira, N Sikdar, D hl, S Dieckhfer, T Quast, S Seisel, ...
    Angewandte Chemie International Edition 60 (16), 9135-9141 2021
    Citations: 105

  • Scanning Electrochemical Cell Microscopy Investigation of Single ZIF‐Derived Nanocomposite Particles as Electrocatalysts for Oxygen Evolution in Alkaline Media
    T Tarnev, HB Aiyappa, A Botz, T Erichsen, A Ernst, C Andronescu, ...
    Angewandte Chemie International Edition 58 (40), 14265-14269 2019
    Citations: 103

  • Cellulose acetate/layered double hydroxide adsorptive membranes for efficient removal of pharmaceutical environmental contaminants
    MD Raicopol, C Andronescu, SI Voicu, E Vasile, AM Pandele
    Carbohydrate polymers 214, 204-212 2019
    Citations: 95

  • Electrocatalytic nanoparticles that mimic the three-dimensional geometric architecture of enzymes: Nanozymes
    TM Benedetti, C Andronescu, S Cheong, P Wilde, J Wordsworth, M Kientz, ...
    Journal of the American Chemical Society 140 (41), 13449-13455 2018
    Citations: 95

  • The efficiency of Co-based single-wall carbon nanotubes (SWNTs) as an AW/EP additive for mineral base oils
    DL Cursaru, C Andronescu, C Pirvu, R Ripeanu
    Wear 290, 133-139 2012
    Citations: 95

  • A Metal–Organic Framework derived CuxOyCz Catalyst for Electrochemical CO2 Reduction and Impact of Local pH Change
    N Sikdar, JRC Junqueira, S Dieckhfer, T Quast, M Braun, Y Song, ...
    Angewandte Chemie International Edition 60 (43), 23427-23434 2021
    Citations: 94

  • Electrocatalytic conversion of glycerol to oxalate on Ni oxide nanoparticles-modified oxidized multiwalled carbon nanotubes
    DM Morales, D Jambrec, MA Kazakova, M Braun, N Sikdar, A Koul, ...
    ACS Catalysis 12 (2), 982-992 2022
    Citations: 92

  • Prospects of value‐added chemicals and hydrogen via electrolysis
    B Garlyyev, S Xue, J Fichtner, AS Bandarenka, C Andronescu
    ChemSusChem 13 (10), 2513-2521 2020
    Citations: 90

  • Role of boron and phosphorus in enhanced electrocatalytic oxygen evolution by nickel borides and nickel phosphides
    J Masa, C Andronescu, H Antoni, I Sinev, S Seisel, K Elumeeva, S Barwe, ...
    ChemElectroChem 6 (1), 235-240 2019
    Citations: 86

  • Operando scanning electrochemical probe microscopy during electrocatalysis
    C Santana Santos, BN Jaato, I Sanjun, W Schuhmann, C Andronescu
    Chemical Reviews 123 (8), 4972-5019 2023
    Citations: 82

  • Graphene-based field effect transistors as biosensors
    C Andronescu, W Schuhmann
    Current Opinion in Electrochemistry 3 (1), 11-17 2017
    Citations: 82