Gaurav Bahuguna
@iitj.ac.in
IITJ-Indian Institute of Technology Jodhpur
Scopus Publications
Scholar Citations
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Scopus Publications
Mohit Verma, Ankita Kumari, Gaurav Bahuguna, Vikas Singh, Vishakha Pareek, Anandita Dhamija, Shubhendra Shukla, Dibyajyoti Ghosh, and Ritu Gupta
American Chemical Society (ACS)
Gaurav Bahuguna, Snehraj Gaur, Avit Patel, Mohit Verma, S. Kiruthika, and Ritu Gupta
Elsevier BV
Gaurav Bahuguna and Fernando Patolsky
Elsevier BV
Gaurav Bahuguna and Fernando Patolsky
Wiley
AbstractDirect sea water splitting as asource of clean renewable energy is indeed a holy grail and necessitates the invention of unprecedented avenues. Toward this goal, for the first time, the effect of thermo‐hydrodynamic processes modulation (electrolyte flow and heating) on water splitting reactions, through the controlling of the nanocatalyst surface environment, is studied thoroughly. A catenated sulphur type‐nickel polysulphide‐based single crystalline, high surface area 3D electrocatalyst (NiS2pSxsurface), with surface‐enriched oxygen evolution reaction (OER, Ni3+) and hydrogen evolution reaction (HER, pSn2−) catalyzing species, is prepared by a single‐step process. Thermo‐hydrodynamic processes‐induced electrochemical analysis demonstrates a dramatic improvement in the electrocatalytic performance of the catalyst, by both flow and temperature modulation. Decoupling contributions from the electrolyte and electrodes heating demonstrate an intrinsic electrode property influence on the overall temperature‐dependent electrochemical performance. Furthermore, a chlorine‐phobic behavior of the NiS2pSxsurface catalyst is observed, even at 80 °C, for direct seawater oxidation, confirming the electrocatalyst potential for direct seawater splitting. Notably, a cell voltage of 1.39 V (at 10 mA cm−2), reaching industrially practical large‐scale of >500 mA cm−2 is observed for additive‐free direct seawater splitting, which is the lowest reported cell voltage to date, even for alkaline additive‐based electrolysers. Consequently, an alternative approach for direct seawater splitting is realized and can be universally extended to any present‐day electrocatalyst platform.
Mohit Verma, Gaurav Bahuguna, Sukhwinder Singh, Ankita Kumari, Dibyajyoti Ghosh, Hossam Haick, and Ritu Gupta
Royal Society of Chemistry (RSC)
2D SnO2 nanosheets based chemiresistive sensor with microporosity and oxygen rich-surface detects ammonia at room temperature in extreme humidity at ppb levels for breath based early disease diagnostics and healthcare.
Gaurav Bahuguna, Boris Filanovsky, and Fernando Patolsky
Elsevier BV
Mohit Verma, Gaurav Bahuguna, Arpit Saharan, Snehraj Gaur, Hossam Haick, and Ritu Gupta
American Chemical Society (ACS)
Xylene is one of the representative indoor pollutants, even in ppb levels, that affect human health directly. Due to the non-polar and less reactive nature of xylene, its room temperature detection is challenging. This work demonstrates a metallic tin-doped Sn-SnO2 nanocomposite under controlled pH conditions via a simple solvothermal route. The Sn nanoparticles are uniformly distributed inside the SnO2 nanospheres of ∼70 nm with a high specific surface area of 118.8 m2/g. The surface of the Sn-SnO2 nanocomposite exhibits strong affinity toward benzene, toluene, ethylbenzene, and xylene (BTEX) compared to other polar volatile organic compounds (VOCs) such as ethanol, acetone, isopropyl alcohol, formaldehyde, and chloroform tested in this study. The sensor's response is highest for xylene among BTEX molecules. Under ambient room temperature conditions, the sensor exhibits a linear response to xylene in the 1-100 ppm range with a sensitivity of ∼255% at 60 ppm within ∼1.5 s and recovers in ∼40 s. The sensor is hardly affected by humidity variations (40-70%), leading to enhanced reliability and repeatability under dynamic environmental conditions. The meso and microporous nanosphere morphology act as a nanocontainer for non-polar VOCs to diffuse inside the nanostructures, providing easy accessibility. The metallic Sn increases the affinity for less reactive xylene at room temperature. Thus, the nanocatalytic Sn-SnO2 nanocomposite is an active gas/VOC sensing material and provides an effective solution for sensing major indoor pollutants under humid conditions.
Snehraj Gaur, Ajay B. Urgunde, Gaurav Bahuguna, S. Kiruthika, and Ritu Gupta
Springer International Publishing
Gaurav Bahuguna, Adam Cohen, Boris Filanovsky, and Fernando Patolsky
Wiley
Efficient neutral water splitting may represent in future a sustainable solution to unconstrained energy requirements, but yet necessitates the development of innovative avenues for achieving the currently unmet required performances. Herein, a novel paradigm based on the combination of electronic structure engineering and surface morphology tuning of earth-abundant 3D-hierarchical binder-free electrocatalysts is demonstrated, via a scalable single-step thermal transformation of nickel substrates under sulfur environment. A temporal-evolution of the resulting 3D-nanostructured substrates is performed for the intentional enhancement of non-abundant highly-catalytic Ni3+ and pSn 2- species on the catalyst surface, concomitantly accompanied with densification of the hierarchical catalyst morphology. Remarkably, the finely engineered NiSx catalyst synthesized via thermal-evolution for 24 h (NiSx -24 h) exhibits an exceptionally low cell voltage of 1.59 V (lower than Pt/C-IrO2 catalytic couple) for neutral water splitting, which represents the lowest value ever reported. The enhanced performance of NiSx -24 h is a multi-synergized consequence of the simultaneous enrichment of oxygen and hydrogen evolution reaction catalyzing species, accompanied by an optimum electrocatalytic surface area and intrinsic high conductivity. Overall, this innovative work opens a route to engineering the active material's electronic structure/morphology, demonstrating novel Ni3+ /pSn 2- -enriched NiSx catalysts which surpass state-of-the-art materials for neutral water splitting.
Mohit Verma, Gaurav Bahuguna, Shubhendra Shukla, and Ritu Gupta
American Chemical Society (ACS)
Gaurav Bahuguna, Adam Cohen, Nimrod Harpak, Boris Filanovsky, and Fernando Patolsky
Wiley
Hydrogen, undoubtedly the next-generation fuel for supplying the world's energy demands, needs economically scalable bifunctional electrocatalysts for its sustainable production. Non-noble transition metal-based electrocatalysts are considered an economic solution for water splitting applications. A single-step solid-state approach for the economically scalable transformation of Ni-based substrates into single-crystalline nickel sulfide nanoplate arrays is developed. X-ray diffraction and transmission electron microscopy measurements reveal the influence of the transformation temperature on the crystal growth direction, which in turn can manipulate the chemical state at the catalyst surface. Ni-based sulfide formed at 450 °C exhibits an enhanced concentration of electrocatalytically-active Ni3+ at their surface and a reduced electron density around sulfur atoms, optimal for efficient H2 production. The Ni-based sulfide electrocatalysts display exceptional electrocatalytic performance for both oxygen and hydrogen evolution, with overpotentials of 170 and 90 mV respectively. Remarkably, the two-electrode cell for overall electrolysis of alkaline water demonstrates an ultra-low cell potential of 1.46 V at 10 mA cm-2 and 1.69 V at 100 mA cm-2 . In addition to the exceptionally low water-splitting cell voltage, this self-standing electrocatalyst is of binderfree nature, with the electrode preparation being a low-cost and single-step process, easily scalable to industrial scales.
Ajay B. Urgunde, Gaurav Bahuguna, Anandita Dhamija, Vipin Kamboj, and Ritu Gupta
Elsevier BV
Gaurav Bahuguna, Mohit Verma, and Ritu Gupta
Royal Society of Chemistry (RSC)
A novel method for fluorination of SnO2 is developed that passivates oxygen defects and increases its electrical conductivity drastically, leading to enhanced charge transport in photoelectrochemical applications.
Indrajit Mondal, Gaurav Bahuguna, Mukhesh K. Ganesha, Mohit Verma, Ritu Gupta, Ashutosh K. Singh, and Giridhar U. Kulkarni
American Chemical Society (ACS)
Fabrication protocols of transparent conducting electrodes (TCEs), including those which produce TCEs of high values of figure of merit, often fail to address issues of scalability, stability, and cost. When it comes to working with high-temperature stable electrodes, one is left with only one and that too, an expensive choice, namely, fluorine-doped SnO2 (FTO). It is rather difficult to replace FTO with a low-cost TCE due to stability issues. In the present work, we have shown that an Al nanomesh fabricated employing the crack template method exhibits extreme thermal stability in air even at 500 °C, compared with that of FTO. In order to fill in the non-conducting island regions present in between the mesh wires, a moderately conducting material SnO2 layer was found adequate. The innovative step employed in the present work relates to the SnO2 deposition without damaging the underneath Al, which is a challenge in itself, as the commonly used precursor, SnCl2 solution, is quite corrosive toward Al. Optimization of spray coating of the precursor while the Al mesh on a glass substrate held at an appropriate temperature was the key to form a stable hybrid electrode. The resulting Al/SnO2 electrode exhibited an excellent transparency of ∼83% at 550 nm and a low sheet resistance of 5.5 Ω/□. SnO2 coating additionally made the TCE scratch-proof and mechanically stable, as the adhesion tape test showed only 8% change in sheet resistance after 1000 cycles. Further, to give FTO-like surface finish, the SnO2 surface was fluorinated by treating with a Selectfluor solution. As a result, the Al/F-SnO2 hybrid film exhibited one order higher surface conductivity with negligible sensitivity toward humidity and volatile organics, while becoming robust toward neutral electrochemical environments. Finally, a custom-designed projection lithography technique was used to pixelate the Al/SnO2 hybrid film for optoelectronic device applications.
Ajay B. Urgunde, Gaurav Bahuguna, Anandita Dhamija, Parijat P. Das, and Ritu Gupta
American Chemical Society (ACS)
The disposal of organic waste materials such as polymers is a serious problem to natural ecosystems as some of them can be non-biodegradable and potentially toxic. Thus, there is immense interest i...
Gaurav Bahuguna, Indrajit Mondal, Mohit Verma, Manish Kumar, Saswata Bhattacharya, Ritu Gupta, and Giridhar U. Kulkarni
American Chemical Society (ACS)
Transparent electronics continues to revolutionize the way we perceive futuristic devices to be. In this work, we propose a technologically advanced volatile organic compound (VOC) sensor in the form of a thin-film transparent display fabricated using fluorinated SnO2 films. A solution-processed method for surface fluorination of SnO2 films using Selectfluor as a fluorinating agent has been developed. The doped fluorine was optimized to be <1%, resulting in a significant increase in conductivity and reduction in persistent photoconductivity accompanied by a faster decay of the photogenerated charge carriers. A combination of these modified properties, together with the intrinsic sensing ability of SnO2, was exploited in designing a transparent display sensor for ppm-level detection of VOCs at an operating temperature of merely 150 °C. Even a transparent metal mesh heater is integrated with the sensor for ease of operation, portability, and less power usage. A sensor reset method is developed while shortening the UV exposure time, enabling complete sensor recovery at low operating temperatures. The sensor is tested toward a variety of polar and nonpolar VOCs (amines, alcohols, carbonyls, alkanes, halo-alkanes, and esters), and it exhibits an easily differentiable response with sensitivity in line with the electron-donating tendency of the functional group present. This work opens up the door for multiplexed sensor arrays with the ability to detect and analyze multiple VOCs with specificity.
Gaurav Bahuguna, Vinod S. Adhikary, Rakesh K. Sharma, and Ritu Gupta
Wiley
Gaurav Bahuguna, Savi Chaudhary, Rakesh K. Sharma, and Ritu Gupta
Wiley
Gaurav Bahuguna, Pura Ram, Rakesh K. Sharma, and Ritu Gupta
Wiley
Vikash C. Janu, Gaurav Bahuguna, Devika Laishram, Kiran P. Shejale, N. Kumar, Rakesh K. Sharma, and Ritu Gupta
Elsevier BV
Abstract Fluorinated α-Fe 2 O 3 nanostructures are synthesized via a facile hydrothermal route using Selectfluor™ (F-TEDA) as a fluorinating as well as growth directing agent. The addition of incrementally increasing amount of F-TEDA to Fe precursor under hydrothermal conditions resulted in preferential growth of α-Fe 2 O 3 along (110) orientation with respect to (104) direction by ~ 35%, the former being important for enhanced charge transport. On increasing fluorination, the heirarchical dendritic-type α-Fe 2 O 3 changes to a snow-flake type structure (F-TEDA-20%) anisotropically growing along the six directions however, at higher F-TEDA concentrations (≥ 30%), loosely held particulate aggregates are seen to be formed. The X-Ray Photoelectron Spectroscopy (XPS) suggest the maximum fluorinarion of α-Fe 2 O 3 at 1.21 at% in 30% F-TEDA. Further, optical absorption studies reveal reduction in optical band gap from 2.10 eV in case of pristine to 1.95 eV for fluorinated α-Fe 2 O 3 . A photoanode made by taking 20% fluorinated α-Fe 2 O 3 in a ratio of 10:90 with respect to TiO 2 (P-25) showed improved performance in dye sensitized solar cells with an increase in efficiency by ~16% in comparision to that of pristine Fe 2 O 3 and TiO 2 . Furthermore, anode consisting of thin films of fluorinated α-Fe 2 O 3 on FTO also exhibit enhanced current density on illumination of ~100 W/m 2 . The increase in photoelectrochemical activity seems to be due to the combination of two factors namely preferential growth of α-Fe 2 O 3 along (110) direction resulting in an improved charge transfer efficiency and reduced recombination losses due to the presence of fluorine.
Gaurav Bahuguna, Vikash C. Janu, Vinay Uniyal, Nagaiah Kambhala, S. Angappane, Rakesh K. Sharma, and Ritu Gupta
Elsevier BV
Abstract Dendritic nanostructures of fluorinated α-Fe 2 O 3 are synthesized using Potassium Ferrocyanide along with Selectfluor™ (F-TEDA), HF, TBABF 4 , NaF and NH 4 F as Fe and F precursors respectively in an in-situ hydrothermal process. The choice of sources is based on the nature of fluorine; F-TEDA uniquely acts as a source for electrophilic fluorine while others are nucleophilic in nature. The effect of fluorination on α-Fe 2 O 3 nanostructures is examined from the interplay between (110) and (104) growth direction and crystallite size by X-Ray diffraction analysis and the amount of fluorination is observed by elemental analysis. A significant change in the magnetic property of α-Fe 2 O 3 is observed for different concentrations of F-TEDA. Pristine α-Fe 2 O 3 undergoes an antiferromagnetic to ferromagnetic transition with saturation magnetization value of ~ 13 emu/g and coercivity of 109.8 Oe. However, α-Fe 2 O 3 nanostructures prepared with HF, NH 4 F, TBABF 4 and NaF in absence of fluorination remain antiferromagnetic despite of changes in preferred orientation and crystallite size. The interesting magnetic properties arising from F-TEDA is attributed to surface fluorination that results in uncompensated surface spins.
Gaurav Bahuguna, Amit Kumar, Neeraj K Mishra, Chitresh Kumar, Aseema Bahlwal, Pratibha Chaudhary, and Rajeev Singh
IOP Publishing
For the first time, any type of plant extract from the medicinally important plant Combretum indicum has been used for the biosynthesis of silver nanoparticles (AgNPs). The present investigation reports the synthesis and characterization of AgNPs using the flower petal extract of Combretum indicum. For monitoring the formation and optical properties of the synthesized nanoparticles, they were analyzed using UV-visible spectroscopy. Apart from this, the luminescence properties were also studied by photoluminescence (PL) spectroscopy. Scanning electron microscopy (SEM) analysis revealed the formation of AgNPs and the surface morphology has been determined. The mean particle diameter using the dynamic light scattering (DLS) technique ranged from 50–120 nm depending upon the reaction time. The atomic percentage of Ag in synthesized NPs and the crystallinity were determined by energy dispersive x-ray (EDX) and x-ray diffraction (XRD), respectively. This green approach of synthesizing AgNPs, using a biologically important plant extract is found to be cost effective, economical, eco-friendly and convenient in synthesis.