Evaluating Bicarbonate Electrolyzer Configurations for Energy-Efficient Formate Production Alessio Mezza, Juqin Zeng, Marco Etzi, Daniele Sassone, Fabrizio C. Pirri, Adriano Sacco Advanced Sustainable Systems, 2026 Reactive carbon capture (RCC) by direct conversion of CO2 capture solutions has emerged as a promising alternative to gas‐fed electrolyzers. Leveraging bicarbonate electrolyzers (BEs), RCC eliminates energy‐intensive steps such as CO2 regeneration and pressurization. Additionally, BEs prevent failures like carbonate salt deposition common in gas‐fed systems. However, intrinsic challenges in BEs, such as higher cell voltages and lower faradaic efficiencies (FEs), result in greater energy consumption during electrolysis compared to gas‐fed electrolyzers. To evaluate whether an RCC chain (RCCC) is more energy‐efficient for formate production than a gas‐fed carbon chain (GFCC), the study optimizes the BE configuration and compares it to a valorization chain requiring a pure, pressurized CO2 stream for gas‐fed electrolyzers. This study shows the most efficient BE setup employs a cation exchange membrane paired with a buffer layer, achieving a FE for formate of ≈75% at a current density of 100 mA cm⁻2 and a cell potential of 3.1 V. Using this optimized BE, the RCCC demonstrates an energetic advantage over GFCCs in scenarios without CO2 recycling. Even with 100% CO2 utilization enabled by recycling systems, RCCC remains competitive. With potential improvements in BE performance, RCCC emerges as a promising strategy for converting CO2 into formate efficiently.
A 3D polymorphic Cu-based ultramicroporous MOF capable of CO2Uptake and Conversion Mariangela Oggianu, Fabio Manna, Valentina Mameli, Carla Cannas, Virginia Guiotto, Valentina Crocellà, Santiago Quesada, Daniele Sassone, Adriano Sacco, Irene I. Gallo Stampino, Raiana Tomazini de Oliveira, Santiago Capelo, Jose Ramon Galan-Mascaros, Norberto Masciocchi, Maria Laura Mercuri Journal of Materials Chemistry A, 2026 Cu(trz 2 An) displays high selectivity and separation efficiency for N/CO₂ and CH/CO₂ mixtures. It also shows promising catalytic activity toward CO₂ reduction, particularly favouring the formation of ethylene.
Size-dependent selectivity of Cu2O nanocube catalysts for CO2 reduction at industrial current densities Marco Etzi, Alessio Mezza, Valentina Bugliarelli, Julien Dangbegnon, Daniele Sassone, Mattia Bartoli, Juqin Zeng, Angelica Chiodoni, Sergio Bocchini, Adriano Sacco, Candido Fabrizio Pirri Electrochimica Acta, 2026 The electrochemical reduction of CO₂ (CO₂RR) to value-added chemicals offers a promising route for carbon recycling and renewable energy storage. Cu-based catalysts are uniquely capable of producing multi-carbon products such as ethylene, but their selectivity is highly sensitive to their morphology. In this work, we systematically investigate the impact of Cu₂O nanocube size (45–600 nm) on CO₂RR performance in both alkaline flow cell and zero-gap electrolyzer, both operating at industrially-relevant current densities. The catalysts were synthesized with well-controlled geometries and edge lengths. In the flow-cell, smaller nanocubes (45–75 nm) exhibited superior selectivity toward ethylene and liquid C 2 products, achieving Faradaic efficiencies toward C 2 products (FE C2 ) of up to 50%, attributed to an optimal balance between edge and facet sites. In contrast, in the zero-gap cell, although 45 nm cubes were the most ethylene-selective, overall FE C2 was reduced and strongly influenced by operational parameters, such as anolyte composition. Long-term tests revealed a trade-off between catalyst durability and ethylene selectivity. These findings demonstrate the critical interplay between nanostructure, testing configuration, and electrolyte, and emphasize the need to assess catalyst performance under industrially-relevant conditions.
A deeper understanding of flooding dynamics in gas diffusion electrodes for CO2 electrolyzer: how interfacial pressure shapes gas–liquid stability Santiago Quesada, Laura Gatti, Matteo Alberghini, Alessio Tommasi, Marco Etzi, Alessio Mezza, Adriano Sacco, Fabrizio C. Pirri, Daniele Sassone Chemical Engineering Journal, 2026 Gas-fed CO 2 electrolyzers are a promising technology for sustainable fuel and chemical production, but their industrial deployment is limited by the instability of gas diffusion electrodes (GDEs), particularly in microfluidic flow cells (MFCs). A key failure mechanism is electrode flooding, which discontinues CO 2 transport and favours hydrogen evolution. Although pressure control across the gas–liquid interface has emerged as a strategy to mitigate flooding, the precise role of differential pressure (ΔP) between gas and liquid side of the GDE remains poorly understood and inconsistently defined in literature. In this work, we systematically explore how gas and liquid pressure management alters the GDE interface, focusing on the understudied “ flow-by ” regime. Using Cu nanoparticles as a model catalyst and operating at industrially relevant current densities (0.5 A cm −2 ), we monitor flooding dynamics through real-time pressure readings, product selectivity analysis, electrochemical impedance spectroscopy (EIS) and field emission scanning electron microscopy (FE-SEM) in different electrochemical setups with several commercial Gas Diffusion Layers (GDL). Our results demonstrate that a ΔP of 30 mbar can fully suppress flooding, preserving catalyst performance and enabling selective CO 2 reduction for over 6 h at 0.5 A cm −2 , almost an order-of-magnitude improvement over uncontrolled system. The experimental ΔP value is confirmed by multiphysics simulations, by modelling capillary-driven liquid invasion and gas transport, in which a predicted onset value of 20 mbar is defined as the required value to prevent the flooding. This work provides the first integrated framework combining pressure tuning, diagnostics, and multi-physics simulation to define and optimize flow-by operation, offering actionable insights for designing robust, high-performance CO 2 electrolyzers. • Integration of multiphysics simulations with high-current experiments • Pressure-driven suppression of flooding • Generalizable methodology for GDE evaluation
Italian Offshore Platform and Depleted Reservoir Conversion in the Energy Transition Perspective Andrea Carpignano, Raffaella Gerboni, Alessio Mezza, Candido Fabrizio Pirri, Adriano Sacco, Daniele Sassone, Alessandro Suriano, Anna Chiara Uggenti, Francesca Verga, Dario Viberti Journal of Marine Science and Engineering, 2023 New hypotheses for reusing platforms reaching their end-of-life have been investigated in several works, discussing the potential conversions of these infrastructures from recreational tourism to fish farming. In this perspective paper, we discuss the conversion options that could be of interest in the context of the current energy transition, with reference to the off-shore Italian scenario. The study was developed in support of the development of a national strategy aimed at favoring a circular economy and the reuse of existing infrastructure for the implementation of the energy transition. Thus, the investigated options include the onboard production of renewable energy, hydrogen production from seawater through electrolyzers, CO2 capture and valorization, and platform reuse for underground fluid storage in depleted reservoirs once produced through platforms. Case histories are developed with reference to a typical, fictitious platform in the Adriatic Sea, Italy, to provide an engineering-based approach to these different conversion options. The coupling of the platform with the underground storage to set the optimal operational conditions is managed through the forecast of the reservoir performance, with advanced numerical models able to simulate the complexity of the phenomena occurring in the presence of coupled hydrodynamic, geomechanical, geochemical, thermal, and biological processes. The results of our study are very encouraging, because they reveal that no technical, environmental, or safety issues prevent the conversion of offshore platforms into valuable infrastructure, contributing to achieving the energy transition targets, as long as the selection of the conversion option to deploy is designed taking into account the system specificity and including the depleted reservoir to which it is connected when relevant. Socio-economic issues were not investigated, as they were out of the scope of the project.
Microporous Polymelamine Framework Functionalized with Re(I) Tricarbonyl Complexes for CO2 Absorption and Reduction Stefania Zappia, Elena Perju, Andrei Bejan, Adina Coroaba, Filippo Bossola, Juqin Zeng, Daniele Sassone, Luminita Marin, Silvia Destri, William Porzio Polymers, 2022 A mixture of polymeric complexes based on the reaction between Re(CO)5Cl and the porous polymeric network coming from the coupling of melamine and benzene-1,3,5-tricarboxaldehyde was obtained and characterized by FTIR, NMR, SEM, XPS, ICP, XRD, and cyclic voltammetry (CV). The formed rhenium-based porous hybrid material reveals a noticeable capability of CO2 absorption. The gas absorption amount measured at 295 K was close to 44 cm3/g at 1 atm. An interesting catalytic activity for CO2 reduction reaction (CO2RR) is observed, resulting in a turn over-number (TON) close to 6.3 under 80 min of test at −1.8 V vs. Ag/AgCl in a TBAPF6 0.1 M ACN solution. A possible use as filler in membranes or columns can be envisaged.
Highly Dispersed Few-Nanometer Chlorine-Doped SnO2Catalyst Embedded in a Polyaniline Matrix for Stable HCOO-Production in a Flow Cell Daniele Sassone, Juqin Zeng, Marco Fontana, M. Amin Farkhondehfal, Candido F. Pirri, Sergio Bocchini ACS Applied Materials and Interfaces, 2022 With the spread of alternative energy plants, electrolysis processes are becoming the protagonists of the future industrial generation. The technology readiness level for the electrochemical reduction of carbon dioxide is still low and is largely based on precious metal resources. In the present work, tin ions are anchored on a polyaniline matrix, via a sonochemical synthesis, forming a few atomic layers of chlorine-doped SnO2 with a total loading of tin atom load of only 7 wt %. This catalyst is able to produce formate (HCOO–) with great selectivity, exceeding 72% of Faradaic efficiency in the first hour of testing in 1 M KHCO3 electrolyte, with a current density of more than 50 mA cm–2 in a 2 M KHCO3 electrolyte flow cell setup. Catalyst stability tests show a stable production of HCOO– during 6 h of measurement, accumulating an overall TONHCOO– of more than 10,000 after 16 h of continuous formate production. This strategy is competitive in drastically reducing the amount of metal required for the overall catalysis.
Polymer-metal complexes as emerging catalysts for electrochemical reduction of carbon dioxide Daniele Sassone, Juqin Zeng, Marco Fontana, Adriano Sacco, M. Amin Farkhondehfal, Monica Periolatto, Candido F. Pirri, Sergio Bocchini Journal of Applied Electrochemistry, 2021 A class of metal-doped polyanilines (PANIs) was synthesized and investigated as electrocatalysts for the carbon dioxide reduction reaction (CO2RR). These materials show good affinity for the electrode substrate and allow to obtain stable binder-free electrodes, avoiding the utilization of expensive ionomer and additives. The emeraldine-base polyaniline (EB-PANI), in absence of metal dopant, shows negligible electrocatalytic activity and selectivity toward the CO2RR. Such behavior significantly improves once EB-PANI is doped with an appropriate cationic metal (Mn, Cu or Sn). In particular, the Sn-PANI outperforms other metal-doped samples, showing a good turnover frequency of 72.2 h−1 for the CO2RR at − 0.99 V vs the reversible hydrogen electrode and thus satisfactory activity of metal single atoms. Moreover, the Sn-PANI also displays impressive stability with a 100% retention of the CO2RR selectivity and an enhanced current density of 4.0 mA cm−2 in a 10-h test. PANI, a relatively low-cost substrate, demonstrates to be easily complexed with different metal cations and thus shows high tailorability. Complexing metal with conductive polymer represents an emerging strategy to realize active and stable metal single-atom catalysts, allowing efficient utilization of metals, especially the raw and precious ones. Graphic abstract
Evaluating Bicarbonate Electrolyzer Configurations for Energy‐Efficient Formate Production A Mezza, J Zeng, M Etzi, D Sassone, FC Pirri, A Sacco Advanced Sustainable Systems 10 (4), 2500098 , 2026 2026.0 Citations: 4
Size-Dependent Selectivity of Cu2O Nanocube Catalysts for CO2 Reduction at Industrial Current Densities M Etzi, A Mezza, V Bugliarelli, J Dangbegnon, D Sassone, M Bartoli, ... Electrochimica Acta, 148114 , 2026 2026.0 Citations: 1
A 3D polymorphic Cu-based ultramicroporous MOF capable of CO 2 Uptake and Conversion M Oggianu, F Manna, V Mameli, C Cannas, V Guiotto, V Crocellà, ... Journal of Materials Chemistry A , 2026 2026.0 Citations: 1
A deeper understanding of flooding dynamics in gas diffusion electrodes for CO2 electrolyzer: how interfacial pressure shapes gas–liquid stability S Quesada, L Gatti, M Alberghini, A Tommasi, M Etzi, A Mezza, A Sacco, ... Chemical Engineering Journal, 171393 , 2025 2025.0 Citations: 5
Italian offshore platform and depleted reservoir conversion in the energy transition perspective A Carpignano, R Gerboni, A Mezza, CF Pirri, A Sacco, D Sassone, ... Journal of Marine Science and Engineering 11 (8), 1544 , 2023 2023.0 Citations: 11
Microporous Polymelamine Framework Functionalized with Re(I) Tricarbonyl Complexes for CO 2 Absorption and Reduction S Zappia, E Perju, A Bejan, A Coroaba, F Bossola, J Zeng, D Sassone, ... Polymers 14 (24), 5472 , 2022 2022.0 Citations: 5
Imidazole-imidazolate pair as organo-electrocatalyst for CO2 reduction on ZIF-8 material D Sassone, S Bocchini, M Fontana, C Salvini, G Cicero, MR Fiorentin, ... Applied Energy 324, 119743 , 2022 2022.0 Citations: 19
Single metal atom catalysts for the electrochemical reduction of CO2 D Sassone Politecnico di Torino , 2022 2022.0
Highly Dispersed Few-Nanometer Chlorine-Doped SnO 2 Catalyst Embedded in a Polyaniline Matrix for Stable HCOO – Production in a Flow Cell D Sassone, J Zeng, M Fontana, MA Farkhondehfal, CF Pirri, S Bocchini ACS applied materials & interfaces 14 (37), 42144-42152 , 2022 2022.0 Citations: 8
A study of the effect of electrode composition on the electrochemical reduction of CO2 J Zeng, M Fontana, A Sacco, D Sassone, CF Pirri Catalysis Today 397, 463-474 , 2022 2022.0 Citations: 30
Microporous Polymelamine Framework Functionalized with Re (I) Tricarbonyl Complexes for CO2 Absorption and Reduction. Polymers 2022, 14, 5472 S Zappia, E Perju, A Bejan, A Coroaba, F Bossola, J Zeng, D Sassone, ... s Note: MDPI stays neutral with regard to jurisdictional claims in published … , 2022 2022.0
Polymer-metal complexes as emerging catalysts for electrochemical reduction of carbon dioxide D Sassone, J Zeng, M Fontana, A Sacco, MA Farkhondehfal, M Periolatto, ... Journal of Applied Electrochemistry 51 (9), 1301-1311 , 2021 2021.0 Citations: 27
Biochar-Supported BiO x for Effective Electrosynthesis of Formic Acid from Carbon Dioxide Reduction J Zeng, P Jagdale, MAO Lourenço, MA Farkhondehfal, D Sassone, ... Crystals 11 (4), 363 , 2021 2021.0 Citations: 24
Biochar-Supported BiOx for Effective Electrosynthesis of Formic Acid from Carbon Dioxide Reduction. Crystals 2021, 11, 363 J Zeng, P Jagdale, MAO Lourenço, MA Farkhondehfal, D Sassone, ... s Note: MDPI stays neutral with regard to jurisdictional claims in published … , 2021 2021.0 Citations: 1
Electrochemical and Photochemical Reduction of CO 2 Catalyzed by Re(I) Complexes Carrying Local Proton Sources L Rotundo, C Garino, E Priola, D Sassone, H Rao, B Ma, M Robert, ... Organometallics 38 (6), 1351-1360 , 2019 2019.0 Citations: 72
Back-Diffusion of Hydroxide Ions Governs Failure Mechanisms in Asymmetric Seawater Electrolyzers P Gardiol, M Etzi, A Sacco, D Sassone Available at SSRN 6520335 , 0
MOST CITED SCHOLAR PUBLICATIONS
Electrochemical and Photochemical Reduction of CO 2 Catalyzed by Re(I) Complexes Carrying Local Proton Sources L Rotundo, C Garino, E Priola, D Sassone, H Rao, B Ma, M Robert, ... Organometallics 38 (6), 1351-1360 , 2019 2019.0 Citations: 72
A study of the effect of electrode composition on the electrochemical reduction of CO2 J Zeng, M Fontana, A Sacco, D Sassone, CF Pirri Catalysis Today 397, 463-474 , 2022 2022.0 Citations: 30
Polymer-metal complexes as emerging catalysts for electrochemical reduction of carbon dioxide D Sassone, J Zeng, M Fontana, A Sacco, MA Farkhondehfal, M Periolatto, ... Journal of Applied Electrochemistry 51 (9), 1301-1311 , 2021 2021.0 Citations: 27
Biochar-Supported BiO x for Effective Electrosynthesis of Formic Acid from Carbon Dioxide Reduction J Zeng, P Jagdale, MAO Lourenço, MA Farkhondehfal, D Sassone, ... Crystals 11 (4), 363 , 2021 2021.0 Citations: 24
Imidazole-imidazolate pair as organo-electrocatalyst for CO2 reduction on ZIF-8 material D Sassone, S Bocchini, M Fontana, C Salvini, G Cicero, MR Fiorentin, ... Applied Energy 324, 119743 , 2022 2022.0 Citations: 19
Italian offshore platform and depleted reservoir conversion in the energy transition perspective A Carpignano, R Gerboni, A Mezza, CF Pirri, A Sacco, D Sassone, ... Journal of Marine Science and Engineering 11 (8), 1544 , 2023 2023.0 Citations: 11
Highly Dispersed Few-Nanometer Chlorine-Doped SnO 2 Catalyst Embedded in a Polyaniline Matrix for Stable HCOO – Production in a Flow Cell D Sassone, J Zeng, M Fontana, MA Farkhondehfal, CF Pirri, S Bocchini ACS applied materials & interfaces 14 (37), 42144-42152 , 2022 2022.0 Citations: 8
A deeper understanding of flooding dynamics in gas diffusion electrodes for CO2 electrolyzer: how interfacial pressure shapes gas–liquid stability S Quesada, L Gatti, M Alberghini, A Tommasi, M Etzi, A Mezza, A Sacco, ... Chemical Engineering Journal, 171393 , 2025 2025.0 Citations: 5
Microporous Polymelamine Framework Functionalized with Re(I) Tricarbonyl Complexes for CO 2 Absorption and Reduction S Zappia, E Perju, A Bejan, A Coroaba, F Bossola, J Zeng, D Sassone, ... Polymers 14 (24), 5472 , 2022 2022.0 Citations: 5
Evaluating Bicarbonate Electrolyzer Configurations for Energy‐Efficient Formate Production A Mezza, J Zeng, M Etzi, D Sassone, FC Pirri, A Sacco Advanced Sustainable Systems 10 (4), 2500098 , 2026 2026.0 Citations: 4
Size-Dependent Selectivity of Cu2O Nanocube Catalysts for CO2 Reduction at Industrial Current Densities M Etzi, A Mezza, V Bugliarelli, J Dangbegnon, D Sassone, M Bartoli, ... Electrochimica Acta, 148114 , 2026 2026.0 Citations: 1
A 3D polymorphic Cu-based ultramicroporous MOF capable of CO 2 Uptake and Conversion M Oggianu, F Manna, V Mameli, C Cannas, V Guiotto, V Crocellà, ... Journal of Materials Chemistry A , 2026 2026.0 Citations: 1
Biochar-Supported BiOx for Effective Electrosynthesis of Formic Acid from Carbon Dioxide Reduction. Crystals 2021, 11, 363 J Zeng, P Jagdale, MAO Lourenço, MA Farkhondehfal, D Sassone, ... s Note: MDPI stays neutral with regard to jurisdictional claims in published … , 2021 2021.0 Citations: 1
Single metal atom catalysts for the electrochemical reduction of CO2 D Sassone Politecnico di Torino , 2022 2022.0
Microporous Polymelamine Framework Functionalized with Re (I) Tricarbonyl Complexes for CO2 Absorption and Reduction. Polymers 2022, 14, 5472 S Zappia, E Perju, A Bejan, A Coroaba, F Bossola, J Zeng, D Sassone, ... s Note: MDPI stays neutral with regard to jurisdictional claims in published … , 2022 2022.0
Back-Diffusion of Hydroxide Ions Governs Failure Mechanisms in Asymmetric Seawater Electrolyzers P Gardiol, M Etzi, A Sacco, D Sassone Available at SSRN 6520335 , 0
