@article {46969, title = {Stress-induced electronic structure modulation of manganese-incorporated Ni2P leading to enhanced activity for water splitting}, journal = {ACS Applied Energy Materials}, volume = {3}, year = {2020}, month = {FEB}, pages = {1271-1278}, type = {Article}, abstract = {

The cornerstone of the emerging hydrogen economy is hydrogen production by water electrolysis with concomitant oxygen generation. Incorporating a third element in metal phosphides can tune the crystalline and electronic structure, hence improving the electrocatalytic properties. In this work, Mn-doped Ni2P with varying ratios of Mn and Ni has been explored as excellent catalysts for water splitting. A complete cell made of the best catalyst Ni1.5Mn0.5P electrodes showed low voltage of 1.75 V at a current density of 10 mA cm(-2) due to enhanced electrical conductivity, induction of tensile stress, enhanced electrochemical surface area, and increased electric dipole upon Mn incorporation.

}, keywords = {Electronic Structure, hydrogen evolution reaction, Oxygen Evolution Reaction, phosphides, water splitting}, issn = {2574-0962}, doi = {10.1021/acsaem.9b02097}, author = {Sarkar, Shreya and Dheer, Lakshay and Vinod, C. P. and Thapa, Ranjit and Waghmare, V. Umesh and Peter, Sebastian C.} } @article {46771, title = {Tweaking palladium electronic structure to attain oxygen reduction activity superior to platinum/C}, journal = {ACS Applied Energy Materials}, volume = {3}, year = {2020}, month = {JUL}, pages = {6127-6132}, type = {Article}, abstract = {

Enhancing oxygen reduction (ORR) activity through alloying is crucial to improve the performance of a fuel-cell catalysts. In this work, we have studied the alloying effects of 4f rare-earth (RE) metals with palladium. The modified catalyst exhibits better activity (E-onset = 1 V and E-1/2 = 0.88 V) and higher selectivity toward H2O (similar to 97\%) compared to the state-of-the-art catalysts due to complete dissociation of O-2. Hirshfeld charge analysis and 2D-electron localization function reveal improved adsorbate-adsorbent interaction on the catalyst surface. This work paves a strategy to design highly selective non-Pt-based catalysts for the ORR by controlling electronic structures and surface oxide formation.

}, keywords = {d-band center, DFT calculation, durability, EuPd, oxygen reduction reaction, YbPd}, issn = {2574-0962}, doi = {10.1021/acsaem.0c01241}, author = {Sarma, Saurav Ch. and Kaja, Sai Manoj and Mishra, Vidyanshu and Vinod, Chathakudath Prabhakaran and Peter, Sebastian C.} } @article {47060, title = {Conductive interface promoted bifunctional oxygen reduction/evolution activity in an ultra-low precious metal based hybrid catalyst}, journal = {Chemical Communications}, volume = {57}, year = {2021}, month = {FEB}, pages = {1951-1954}, type = {Article}, abstract = {

Ultra low PtPd alloy deposited on Ni12P5 nanostructures (PtPd/Ni12P5) exhibited enhanced ORR activity (onset: 1.003 V and E-1/2:0.95 V) on par with commercial Pt/C and superior OER activity with 81\% reduction of the precious metal compared to the commercial catalyst.

}, issn = {1359-7345}, doi = {10.1039/d0cc08225b}, author = {Sarkar, Shreya and Varghese, Merin and Vinod, C. P. and Peter, Sebastian C.} } @article {47037, title = {Conductive interface promoted bifunctional oxygen reduction/evolution activity in an ultra-low precious metal based hybrid catalyst (vol 57, pg 1951, 2021)}, journal = {Chemical Communications}, volume = {57}, year = {2021}, month = {MAR }, pages = {2824}, type = {Correction}, issn = {1359-7345}, doi = {10.1039/d1cc90088a}, author = {Sarkar, Shreya and Varghese, Merin and Vinod, C. P. and Peter, Sebastian C.} } @article {47068, title = {Operando generated ordered heterogeneous catalyst for the selective conversion of CO2 to methanol}, journal = {ACS Energy Letters}, volume = {6}, year = {2021}, month = {FEB }, pages = {509-516}, type = {Article}, abstract = {

The discovery of new materials for efficient transformation of carbon dioxide (CO2) into desired fuel can revolutionize large-scale renewable energy storage and mitigate environmental damage due to carbon emissions. In this work, we discovered an operando generated stable Ni-In kinetic phase that selectively converts CO2 to methanol (CTM) at low pressure compared to the state-of-the-art materials. The catalytic nature of a well-known methanation catalyst, nickel, has been tuned with the introduction of inactive indium, which enhances the CTM process. The remarkable change in the mechanistic pathways toward methanol production has been mapped by operando diffuse reflectance infrared Fourier transform spectroscopy analysis, corroborated by first-principles calculations. The ordered arrangement and pronounced electronegativity difference between metals are attributed to the complete shift in mechanism. The approach and findings of this work provide a unique advance toward the next-generation catalyst discovery for going beyond the state-of-the-art in CO2 reduction technologies.

}, issn = {2380-8195}, doi = {10.1021/acsenergylett.0c02614}, author = {Cherevotan, Arjun and Raj, Jithu and Dheer, Lakshay and Roy, Soumyabrata and Sarkar, Shreya and Das, Risov and Vinod, Chathakudath P. and Xu, Shaojun and Wells, Peter and Waghmare, V, Umesh and Peter, Sebastian C.} } @article {47729, title = {Structure-tailored non-noble metal-based ternary chalcogenide nanocrystals for pt-like electrocatalytic hydrogen production}, journal = {ChemSusChem}, volume = {14}, year = {2021}, month = {AUG }, pages = {3074-3083}, type = {Article}, abstract = {A facile microwave-assisted strategy was employed to synthesize Ni3Bi2S2 nanocrystals. Variation in the synthesis conditions tuned the composition of monoclinic and orthorhombic phases of Ni3Bi2S2. The electrochemical hydrogen evolution activity of the catalyst with highest percentage of monoclinic phase demonstrated a negligible onset potential of only 24 mV close to that of state-of-the-art Pt/C with an overpotential as low as 88 mV. Density functional theory calculations predicted the monoclinic phase exhibit the lowest adsorption free energy corresponding to hydrogen adsorption (Delta GadsH*) and, therefore, the highest hydrogen evolution activity amongst the considered phases. The quasi-2D structure of monoclinic phase facilitated an increased charge-transfer between Ni and Bi, favoring the downward shift of the d-band center to enhance the catalytic activity.}, keywords = {charge transfer, electrocatalysis, hydrogen evolution reaction, Nanomaterials, ternary chalcogenides}, issn = {1864-5631}, doi = {10.1002/cssc.202100967}, author = {Sarkar, Shreya and Rawat, Abhishek and Das, Tisita and Gaboardi, Mattia and Chakraborty, Sudip and Vinod, C. P. and Peter, Sebastian C.} } @article {47105, title = {Unveiling the roles of lattice strain and descriptor species on pt-like oxygen reduction activity in Pd-Bi catalysts}, journal = {ACS Catalysis}, volume = {11}, year = {2021}, month = {JAN}, pages = {800-808}, type = {Article}, abstract = {

A facile non-template-assisted mechanical ball milling technique was employed to generate a PdBi alloy catalyst. The induced lattice strain upon the milling time caused a shift of the d-band center, thereby enhancing the oxygen reduction reaction (ORR) catalytic activity. Additionally, the Pd-O reduction potential and adsorbed OH coverage used as descriptors stipulated the cause of the enhanced ORR activity upon the increased milling interval. Redox properties of surface Pd are directly correlated with a positive shift in the Pd-O reduction potential and OH surface coverage. Hence, by deconvoluting the lattice strain and the role of the descriptor species we achieved a catalyst system with a specific activity 5.4X higher than that of commercial Pt/C, as well as an improved durability. The experimental observation is well-corroborated by a theoretical simulation done by inducing strain to the system externally.

}, keywords = {charge-transfer, electrocatalysis, fuel cell, Lattice strain, oxygen reduction, Pt-like activity}, issn = {2155-5435}, doi = {10.1021/acscatal.0c03415}, author = {Sarkar, Shreya and Ramarao, S. D. and Das, Tisita and Das, Risov and Vinod, C. P. and Chakraborty, Sudip and Peter, Sebastian C.} } @article {48099, title = {Green transformation of CO2 to ethanol using water and sunlight by the combined effect of naturally abundant red phosphorus and Bi2MoO6}, journal = {Energy \& Environmental Science}, volume = {15}, year = {2022}, month = {MAY }, pages = {1967-1976}, type = {Article}, abstract = {

Direct photocatalytic conversion of CO2 to ethanol remains a scientific challenge because of the sluggish kinetics of C-C coupling and complex multielectron transfer processes. To achieve a green transformation of CO2 to C1+ products using naturally abundant sunlight and water requires the smart design of an efficient catalyst by selecting the right combination of atoms either in elemental or in compound form. Herein, we report a composite photocatalyst composed of earth abundant red phosphorus (RP) in nano-sheet morphology decorated with Bi2MoO6 nano-particles. The composite synthesised by a facile ultrasonication method produces 51.8 mu mol g(-1) h(-1) of ethanol from CO2. The ability of RP for the conversion of CO2 to C1 has been altered by the introduction of Bi2MoO6. In situ Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS) and Kinetic Isotopic Effect (KIE) analysis shed light on the mechanistic pathway, which propose that the presence of Bi-Mo dual sites play a crucial role in the C-C coupling toward the formation of ethanol. Spectroscopic evidence and isotope labeling experiments suggest that the intermediate OCH3* is the key active species for ethanol formation via self-coupling followed by proton transfer.

}, issn = {1754-5692}, doi = {10.1039/d1ee02976b}, author = {Das, Risov and Das, Kousik and Ray, Bitan and Vinod, Chathakudath P. and Peter, Sebastian C.} } @article {48210, title = {Improvement in oxygen evolution performance of NiFe layered double hydroxide grown in the presence of 1T-Rich MoS2}, journal = {ACS Applied Materials \& Interfaces}, volume = {14}, year = {2022}, month = {JUL}, pages = {31951-31961}, type = {Article}, abstract = {

NiFe layered double hydroxide (NiFe LDH) grown in the presence of MoS2 (rich in 1T phase) shows exceptional performance metrics for alkaline oxygen evolution reaction (OER) in this class of composites. The as-prepared NiFe LDH/MoS2 composite (abbreviated as MNF) exhibits a low overpotential (eta(10)) of 190 mV; a low Tafel slope of 31 mV dec(-1); and more importantly, a high stability in its performance manifested by the delivery of current output for 45 h. It is important to note that this could be achieved with an exceedingly low loading of 0.14 mg cm(-2). The mass activity of this composite (97 A g(-1)) is about 14 times greater than that of the conventional RuO2 (7 A g(-1) ) at eta = 200 mV. When normalized with respect to the total metal content, a mass activity of 1000 A g(-1) (eta = 300 mV) was achieved. Impedance analysis further reveals that the significant reduction in charge-transfer resistance and hence high current density (5 times greater as compared to NiFe LDH at eta = 300 mV) observed for MNF is associated with interfacial adsorption kinetics of intermediates (R-1). Significant enhancement in the intrinsic activity of MNF over LDH has been observed through normalization of current with the electrochemically active surface area. Computational studies suggest that the Ni centers in the composite act as the active sites for OER, which is well-corroborated with the observed postreaction appearance of Ni3+ species.

}, keywords = {Impedance, LDH-MoS2 hybrid electrocatalyst, mass activity, OER, overpotential}, issn = {1944-8244}, doi = {10.1021/acsami.2c06210}, author = {Chakraborty, Soumita and Marappa, Shivanna and Agarwal, Sakshi and Bagchi, Debabrata and Rao, Ankit and Vinod, Chathakudath P. and Peter, Sebastian C. and Singh, Abhishek and Eswaramoorthy, Muthusamy} } @article {48188, title = {Influence of support textural property on CO2 to methane activity of Ni/ SiO2 catalysts}, journal = {Applied Catalysis B-Environmental}, volume = {317}, year = {2022}, month = {NOV}, pages = {121692}, type = {Article}, abstract = {

In this work, we elucidated the role of physicochemical textural properties of inert support on the catalyst ac-tivity by impregnating Ni on ordered mesoporous silica (SBA-15 and MCM-41) and non-mesoporous silica (nMPS). The catalyst Ni/SBA-15 exhibited the best CO2 conversion (83\%) and product selectivity (99.9 \%) followed by Ni/MCM-41 and the least by Ni/nMPS. The difference in the nature of the catalyst, degree of nanoparticle distribution and nanoparticle encapsulation by different silica support were studied by N2 adsorption-desorption and X-ray photoelectron spectroscopy (XPS) experiments. The Operando Diffused Reflec-tance Infrared Fourier Transform Spectroscopy were used to understand the variance in reaction pathway which is accredited to the textural properties of the support. The SBA-15 supported Ni catalyst followed dissociative CO pathway while MCM-41 and nMPS reacted through associative formate mechanism as major pathway. These findings provide a novel perspective on CO2 hydrogenation over Ni-silica, allowing us to tune both activity and selectivity.

}, keywords = {CO2 methanation, DRIFTS, Mesoporous silica support, Textural properties}, issn = {0926-3373}, doi = {10.1016/j.apcatb.2022.121692}, author = {Cherevotan, Arjun and Ray, Bitan and Churipard, Sathyapal R. and Kaur, Komalpreet and Gautam, Ujjal K. and Vinod, Chathakudath P. and Peter, Sebastian C.} } @article {48157, title = {Morphology-tuned Pt3Ge accelerates water dissociation to industrial-standard hydrogen production over a wide pH range}, journal = {Advanced Materials}, volume = {34}, year = {2022}, month = {JUL}, pages = {2202294}, type = {Article}, abstract = {

The discovery of novel materials for industrial-standard hydrogen production is the present need considering the global energy infrastructure. A novel electrocatalyst, Pt3Ge, which is engineered with a desired crystallographic facet (202), accelerates hydrogen production by water electrolysis, and records industrially desired operational stability compared to the commercial catalyst platinum is introduced. Pt3Ge-(202) exhibits low overpotential of 21.7 mV (24.6 mV for Pt/C) and 92 mV for 10 and 200 mA cm(-2) current density, respectively in 0.5 m H2SO4. It also exhibits remarkable stability of 15 000 accelerated degradation tests cycles (5000 for Pt/C) and exceptional durability of 500 h (@10 mA cm(-2)) in acidic media. Pt3Ge-(202) also displays low overpotential of 96 mV for 10 mA cm(-2) current density in the alkaline medium, rationalizing its hydrogen production ability over a wide pH range required commercial operations. Long-term durability (\>75 h in alkaline media) with the industrial level current density (\>500 mA cm(-2)) has been demonstrated by utilizing the electrochemical flow reactor. The driving force behind this stupendous performance of Pt3Ge-(202) has been envisaged by mapping the reaction mechanism, active sites, and charge-transfer kinetics via controlled electrochemical experiments, ex situ X-ray photoelectron spectroscopy, in situ infrared spectroscopy, and in situ X-ray absorption spectroscopy further corroborated by first principles calculations.

}, keywords = {Electrochemistry, hydrogen production, intermetallics, water electrolysis}, issn = {0935-9648}, doi = {10.1002/adma.202202294}, author = {Mondal, Soumi and Sarkar, Shreya and Bagchi, Debabrata and Das, Tisita and Das, Risov and Singh, Ashutosh Kumar and Prasanna, Ponnappa Kechanda and Vinod, C. P. and Chakraborty, Sudip and Peter, Sebastian C.} } @article {48415, title = {Noble-metal-free heterojunction photocatalyst for selective CO2 reduction to methane upon induced strain relaxation}, journal = {ACS Catalysis}, volume = {12}, year = {2022}, month = {JAN }, pages = {687-697}, type = {Article}, abstract = {

Sunlight-driven CO2 hydrogenation has drawn tremendous attention. However, selective CH4 formation via CO2 photoreduction is very challenging. Herein, we report a metal oxide semiconductor heterojunction consisting of BiVO4 and WO3 as a photocatalyst for the efficient conversion of carbon dioxide (CO2) selectively to methane (105 mu mol g(-1) h(-1)) under visible light in the absence of a sacrificial agent. Wise selection of the reaction medium and the strategically tuned heterojunction upon strain relaxation suppresses the competitive hydrogen generation reaction. The detailed photophysical, photoelectrochemical, and X-ray absorption spectroscopy studies pointed to the Z-scheme mechanism of electron transfer, which favors superior electron and hole separation compared to the individual components of the composite catalyst and other well-known photocatalysts reported for CO2 reduction. The observations are further corroborated by experimental diffuse reflectance infrared Fourier transform spectroscopy and theoretical density-functional theory calculations, which reveal that the heterojunction has a lower free-energy barrier for CO2 conversion to CH4 due to the larger stabilization of the *CH2O intermediate on the strain-relaxed heterojunction surface, in comparison to the pristine BiVO4 surface. The present work provides fundamental insights for constructing high-performance heterojunction photocatalysts for the selective conversion of CO2 to desired chemicals and fuels.

}, keywords = {CO2 reduction, heterostructure, methane, Photocatalysis, Z-scheme}, issn = {2155-5435}, doi = {10.1021/acscatal.1c04587}, author = {Das, Risov and Sarkar, Shreya and Kumar, Ritesh and Ramarao, Seethiraju D. and Cherevotan, Arjun and Jasil, Mohammed and Vinod, Chathakudath P. and Singh, Abhishek Kumar and Peter, Sebastian C.} } @article {48094, title = {Potential- and time-dependent dynamic nature of an oxide-derived pdin nanocatalyst during electrochemical CO2 reduction}, journal = {ACS Nano}, volume = {16}, year = {2022}, month = {APR}, pages = {6185-6196}, type = {Article}, abstract = {

Electrochemical reduction of CO2 into valuable fuels and chemicals is a promising route of replacing fossil fuels by reducing CO2 emissions and minimizing its adverse effects on the climate. Tremendous efforts have been carried out for designing efficient catalyst materials to selectively produce the desired product in high yield from CO2 by the electrochemical process. In this work, a strategy is reported to enhance the electrochemical CO2 reduction reaction (ECO2RR) by constructing an interface between a metal-based alloy (PdIn) nanoparticle and an oxide (In2O3), which was synthesized by a facile solution method. The oxide-derived PdIn surface has shown excellent eCO(2)RR activity and enhanced CO selectivity with a Faradaic efficiency (FE) of 92.13\% at -0.9 V (vs RHE). On the other hand, surface PdO formation due to charge transfer on the bare PdIn alloy reduces the CO2RR activity. With the support of in situ (EXAFS and IR) and ex situ (XPS, Raman) spectroscopic techniques, the optimum presence of the Pd-In-O interface has been identified as a crucial parameter for enhancing eCO(2)RR toward CO in a reducing atmosphere. The influence of eCO(2)RR duration is reported to affect the overall performance by switching the product selectivity from H-2 (from water reduction) to CO (from eCO(2)RR) on the oxide-derived alloy surface. This work also succeeded in the multifold enhancement of the current density by employing the gas diffusion electrode (GDE) and optimizing its process parameters in a flow cell configuration.

}, keywords = {CO2 reduction, Electrochemistry, heterostructure interface, in situ mechanism, nanocatalyst}, issn = {1936-0851}, doi = {10.1021/acsnano.1c11664}, author = {Bagchi, Debabrata and Sarkar, Shreya and Singh, Ashutosh Kumar and Vinod, Chathakudath P. and Peter, Sebastian C.} } @article {48098, title = {Strain-enhanced phase transformation of iron oxide for higher alcohol production from CO2}, journal = {ACS Catalysis}, volume = {12}, year = {2022}, month = {SEP}, pages = {11118-11128}, type = {Article}, abstract = {

Conversion of CO2 to higher alcohols (HAs) and higher hydrocarbons (HCs) has a greater advantage compared to C1 products because of their high energy density and wide range of applications in daily life. Despite the immense potential of these chemicals, not much of scientific research has been focused on the conversion of CO2 to HAs. In the present work, we have introduced the concept of strain in designing the material to enhance the CO(2 )to HA performance. We introduced strain in a traditional iron-based catalyst, Fe2O3, by the introduction of indium (In), which facilitates the selective conversion of CO2 to HA. An optimum strain favored a 36.7\% CO2 conversion with a 42\% HA selectivity, and a record yield of 15.42\%. The strain has been tuned further with the introduction of K as a promoter. The introduced strain upon In substitution and K promotion favored the conversion of CO2, which is mapped by powder X-ray diffraction, X-ray photoelectron spectroscopy, and X-ray absorption spectroscopy. Further, the change in the mechanism upon In incorporation and K promotion has been probed by in situ diffuse reflectance infrared fourier transform spectroscopy, and it is found that the OCHx intermediate, which produces HAs, is more prominent upon In substitution, which favored the enhancement of HA production compared to that of pristine Fe2O3.

}, keywords = {CO2 to HA, Fischer-Tropsch synthesis (FTS), Phase transformation, reverse water gas shift (RWGS) reaction, strain}, issn = {2155-5435}, doi = {10.1021/acscatal.2c0318311118}, author = {Goud, Devender and Churipard, Sathyapal R. and Bagchi, Debabrata and Singh, Ashutosh Kumar and Riyaz, Mohd and Vinod, C. P. and Peter, Sebastian C.} } @article {48088, title = {Structure-tailored surface oxide on Cu-Ga intermetallics enhances CO2 reduction selectivity to methanol at ultralow potential}, journal = {Advanced Materials}, volume = {34}, year = {2022}, month = {MAY}, pages = {2109426}, type = {Article}, abstract = {

Electrochemical CO2 reduction reaction (eCO(2)RR) is performed on two intermetallic compounds formed by copper and gallium metals (CuGa2 and Cu9Ga4). Among them, CuGa2 selectively converts CO2 to methanol with remarkable Faradaic efficiency of 77.26\% at an extremely low potential of -0.3 V vs RHE. The high performance of CuGa2 compared to Cu9Ga4 is driven by its unique 2D structure, which retains surface and subsurface oxide species (Ga2O3) even in the reduction atmosphere. The Ga2O3 species is mapped by X-ray photoelectron spectroscopy (XPS) and X-ray absorption fine structure (XAFS) techniques and electrochemical measurements. The eCO(2)RR selectivity to methanol are decreased at higher potential due to the lattice expansion caused by the reduction of the Ga2O3, which is probed by in situ XAFS, quasi in situ powder X-ray diffraction, and ex situ XPS measurements. The mechanism of the formation of methanol is visualized by in situ infrared (IR) spectroscopy and the source of the carbon of methanol at the molecular level is confirmed from the isotope-labeling experiments in presence of (CO2)-C-13. Finally, to minimize the mass transport limitations and improve the overall eCO(2)RR performance, a poly(tetrafluoroethylene)-based gas diffusion electrode is used in the flow cell configuration.

}, keywords = {(2) reduction, CO, Electrochemistry, Methanol}, issn = {0935-9648}, doi = {10.1002/adma.202109426}, author = {Bagchi, Debabrata and Raj, Jithu and Singh, Ashutosh Kumar and Cherevotan, Arjun and Roy, Soumyabrata and Manoj, Kaja Sai and Vinod, C. P. and Peter, Sebastian C.} } @article {48181, title = {Tuning the hybridization and charge polarization in metal nanoparticles dispersed over Schiff base functionalized SBA-15 enhances CO2 capture and conversion to formic acid}, journal = {Journal of Materials Chemistry A}, volume = {10}, year = {2022}, month = {SEP}, pages = {18354-18362}, type = {Article}, abstract = {

Different Schiff base functionalized SBA-15 materials were synthesized through condensation reactions between 3-aminopropyltriethoxysilane (APTES) and different aldehydes (glutaraldehyde and butyraldehyde) over a mesoporous silica, SBA-15 (APTES-GLU/SBA-15 and APTES-BUT/SBA-15). Both static and dynamic experiments have been used for testing the CO2 capture efficiency of these materials. The hybridization of the N atom in APTES has been tuned from sp(3) to sp(2) upon condensation facilitating optimum CO2 capture in the direct synthesis of APTES-GLU/SBA-15. The undesirable oxides of nitrogen have been removed during the synthesis process to improve the CO2 capture efficiency. These materials were employed as supports for Pd-Ag and Pd-Ni bimetallic systems for the selective conversion of the captured CO2 to formic acid (FA) in 0.5 M KHCO3 solution. The Pd-Ni catalyst system exhibited enhanced CO2 to FA conversion activity compared to other heterogeneous systems, which is similar to 4 times better than that of the Pd-Ag system in this study. The X-ray absorption studies over the catalyst material confirmed that the relatively electron-deficient Ni in Pd-Ni compared to Ag in Pd-Ag favoured higher charge polarization between the metals in the Pd-Ni system enhancing the CO2 to FA conversion. The experimental observations are well supported by the DFT calculations.

}, issn = {2050-7488}, doi = {10.1039/d2ta03690h}, author = {Cherevotan, Arjun and Ray, Bitan and Yadav, Anish and Bagchi, Debabrata and Singh, Ashutosh Kumar and Riyaz, Mohd and Churipard, Sathyapal R. and Naral, Vinay and Kaur, Komalpreet and Gautam, Ujjal K. and Vinod, Chathakudath P. and Peter, Sebastian C.} } @article {48951, title = {Distortion-induced interfacial charge transfer at single cobalt atom secured on ordered intermetallic surface enhances pure oxygen production}, journal = {ACS Nano}, volume = {17}, year = {2023}, month = {NOV }, pages = {23169-23180}, type = {Journal Article}, abstract = {

In this work, atomic cobalt (Co) incorporation into the Pd2Ge intermetallic lattice facilitates operando generation of a thin layer of CoO over Co-substituted Pd2Ge, with Co in the CoO surface layer functioning as single metal sites. Hence the catalyst has been titled Co-1-CoO-Pd2Ge. High-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, and X-ray absorption spectroscopy confirm the existence of CoO, with some of the Co bonded to Ge by substitution of Pd sites in the Pd2Ge lattice. The role of the CoO layer in the oxygen evolution reaction (OER) has been verified by its selective removal using argon sputtering and conducting the OER on the etched catalyst. In situ X-ray absorption near-edge structure and extended X-ray absorption fine structure spectroscopy demonstrate that CoO gets transformed to CoOOH (Co3+) in operando condition with faster charge transfer through Pd atoms in the core Pd2Ge lattice. In situ Raman spectroscopy depicts the emergence of a CoOOH phase on applying potential and shows that the phase is stable with increasing potential and time without getting converted to CoO2. Density functional theory calculations indicate that the Pd2Ge lattice induces distortion in the CoO phase and generates unpaired spins in a nonmagnetic CoOOH system resulting in an increase in the OER activity and durability. The existence of spin density even after electrocatalysis is verified from electron paramagnetic resonance spectroscopy. We have thus successfully synthesized intermetallic supported CoO during synthesis and rigorously verified the role played by an intermetallic Pd2Ge core in enhancing charge transfer, generating spin density, improving electrochemical durability, and imparting mechanical stability to a thin CoOOH overlayer. Differential electrochemical mass spectrometry has been explored to visualize the instantaneous generation of oxygen gas during the onset of the reaction.

}, keywords = {DEMS, interfacial charge transfer, Intermetallic, long-termstability, operando spectroscopic techniques, Oxygen Evolution Reaction, structuraldistortion}, issn = {1936-0851}, doi = {10.1021/acsnano.3c09680}, author = {Mondal, Soumi and Riyaz, Mohd and Bagchi, Debabrata and Dutta, Nilutpal and Singh, Ashutosh Kumar and Vinod, Chathakudath P. and Peter, Sebastian C.} } @article {48450, title = {Intrinsic charge polarization in Bi19S27Cl3 nanorods promotes selective C-C coupling reaction during photoreduction of CO2 to ethanol}, journal = {Advanced Materials}, volume = {35}, year = {2023}, month = {FEB}, type = {Article}, abstract = {

Obtaining multi-carbon products via CO2 photoreduction is a major catalytic challenge involving multielectron-mediated C-C bond formation. Complex design of multicomponent interfaces that are exploited to achieve this chemical transformation, often leads to untraceable deleterious changes in the interfacial chemical environment affecting CO2 conversion efficiency and product selectivity. Alternatively, robust metal centers having asymmetric charge distribution can effectuate C-C coupling reaction through the stabilization of intermediates, for desired product selectivity. However, generating inherent charge distribution in a single component catalyst is a difficult material design challenge. Here, a novel photocatalyst, Bi19S27Cl3, is presented which selectively converts CO2 to a C-2 product, ethanol, in high yield under visible light irradiation. Structural analysis through transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and X-ray absorption spectroscopy reveals the presence of charge polarized bismuth centers in Bi19S27Cl3. The intrinsic electric field induced by charge polarized bismuth centers renders better separation efficiency of photogenerated electron-hole pair. Furthermore, charge polarized centers yield better adsorption of CO* intermediate and accelerate the rate determining C-C coupling step through the formation of OCCOH intermediate. Formation of these intermediates is experimentally mapped by in situ Fourier-transform infrared spectroscopy and further confirmed by theoretical calculation.

}, keywords = {C-C coupling, charge polarization, CO2 reduction, Ethanol, Photocatalysis}, issn = {0935-9648}, doi = {10.1002/adma.202205994}, author = {Das, Kousik and Das, Risov and Riyaz, Mohd and Parui, Arko and Bagchi, Debabrata and Singh, Ashutosh Kumar and Singh, Abhishek Kumar and Vinod, Chathakudath P. and Peter, Sebastian C.} } @article {48820, title = {Metal deficiency tailored by the 18-electron rule stabilizes metal-based inorganic compounds}, journal = {Chemistry of Materials}, volume = {35}, year = {2023}, month = {JUL}, pages = {6050-6058}, type = {Article}, abstract = {

The 18-electron (18-e(-)) rule is typicallyrestrictedto predicting the stability of transition-metal-based complexes. Herein,we report the use of the 18-e(-) to predict the stabilityin a family of intermetallics MNiSn (M = V, Cr, Fe, and Co) crystallizingin the Co1.75Ge structure type. Site deficiencies at theM site obtained from single-crystal X-ray diffraction are understoodas attaining a stable noble gas electronic configuration. The densityfunctional theory -based structure calculation confirms that the deficientstructure is more stable than the ideal occupation available at thecrystal lattice. MnNiSn, which crystallizes in the half-Heusler crystalstructure, depicts the role of covalent radii of the constituent elementsin determining the crystal structure. Using X-ray absorption spectroscopyand X-ray photoelectron spectroscopy, the local structure of the above-mentionedcompounds was also elucidated, supporting the role of deficiency tunedvalence fluctuation to attain a 18-e(-) configurationthat eventually leads to the formation of stable compounds.

}, issn = {0897-4756}, doi = {10.1021/acs.chemmater.3c01142}, author = {Singh, Ashutosh Kumar and Mumbaraddi, Dundappa and Mishra, Vidyanshu and Roy, Soumyabrata and Vinod, C. P. and Peter, Sebastian C.} } @article {48962, title = {Wurtzite CuGaS2 with an in-situ-formed CuO layer photocatalyzes CO2 conversion to ethylene with high selectivity}, journal = {Angewandte chemie-international edition}, volume = {62}, year = {2023}, month = {FEB 20}, type = {Article}, abstract = {

We present surface reconstruction-induced C-C coupling whereby CO2 is converted into ethylene. The wurtzite phase of CuGaS2. undergoes in situ surface reconstruction, leading to the formation of a thin CuO layer over the pristine catalyst, which facilitates selective conversion of CO2 to ethylene (C2H4). Upon illumination, the catalyst efficiently converts CO2 to C2H4 with 75.1 \% selectivity (92.7 \% selectivity in terms of R-electron) and a 20.6 mu mol g(-1) h(-1) evolution rate. Subsequent spectroscopic and microscopic studies supported by theoretical analysis revealed operando-generated Cu2+, with the assistance of existing Cu+, functioning as an anchor for the generated *CO and thereby facilitating C-C coupling. This study demonstrates strain-induced in situ surface reconstruction leading to heterojunction formation, which finetunes the oxidation state of Cu and modulates the CO2 reduction reaction pathway to selective formation of ethylene.

}, keywords = {C-C coupling, charge polarization, CO2 reduction, Photocatalysis}, issn = {1433-7851}, doi = {10.1002/anie.202216613}, author = {Chakraborty, Subhajit and Das, Risov and Riyaz, Mohd and Das, Kousik and Singh, Ashutosh Kumar and Bagchi, Debabrata and Vinod, Chathakudath P. and Peter, Sebastian C.} } @article {49059, title = {Unraveling the cooperative mechanisms in ultralow copper-loaded WC@NGC for enhanced CO2 electroreduction to acetic acid}, journal = {Chemistry of Materials }, volume = {36}, year = {2024}, month = {MAR }, pages = {3464-3476}, type = {Article}, abstract = {

Electrochemical CO2 reduction reaction (eCO(2)RR) has been explored on tungsten carbide (WC) nanoparticles embedded on N-doped graphitic carbon (NGC), demonstrating excellent activity toward the formation of acetic acid at an extremely lower potential. The activity has been further enhanced by loading ultralow copper sites into the catalyst system, exhibiting 80.02\% Faradaic efficiency (FE) toward acetic acid at an applied potential of -0.3 V (vs RHE). Potential-dependent in situ infrared (IR), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, ex situ extended X-ray absorption fine structure (EXAFS) studies, and computational analysis confirm that synergy between uniformly dispersed Cu atoms and WC lattice plays a crucial role in the formation of acetic acid with high FE at a lower potential. It has been observed that the W atom of WC strongly chemisorbs CO2 with a significant change in the C-O bond length and the O-C-O bond angle, in contrast to weaker adsorption on Cu-based catalyst surfaces. The presence of a Cu site enhances the adsorption of CO2, thereby increasing the possibility of C-C coupling kinetically. Most importantly, hydrogen evolution predominates on the catalyst{\textquoteright}s surface at higher applied potentials (-0.5 to -1.1 V vs RHE), elucidating the mechanism underlying enhanced charge transfer between copper and WC, a phenomenon ascertained through in situ IR spectroscopy and ex situ XPS analysis

}, issn = {0897-4756}, doi = {10.1021/acs.chemmater.4c00405}, author = {Bagchi, Debabrata and Riyaz, Mohd and Raj, Jithu and Roy, Soumyabrata and Singh, Ashutosh Kumar and Cherevotan, Arjun and Vinod, Chathakudath P. and Peter, Sebastian C.} } @article {49534, title = {Metal deficiency tuned charge transfer in intermetallic Ni2-xSn (x =0.37-0.65) enhances selective conversion of furfural to furfuryl alcohol towards the theoretical limit}, journal = {Journal of Materials Chemistry A}, volume = {13}, year = {2025}, month = {FEB}, pages = {6042-6048}, type = {Article}, abstract = {

Heterogeneous catalysis facilitated by intermetallic nanoparticles has recently been the subject of increased scrutiny, given the enhanced selectivity and stability they bestow on many chemical reactions compared to their monometallic components. This paper explores a series of Ni-Sn (Ni2-xSn, where x = 0.65, 0.5, 0.37) intermetallic compounds supported on a high-surface-area support, SBA-15, as catalysts for the selective hydrogenation of furfural to furfuryl alcohol. Rietveld refinements of the X-ray diffraction data show catalysts with mixed intermetallic phases that assist in the catalysis. At the same time, X-ray photoelectron spectroscopy (XPS) studies and X-ray absorption studies indicate the role played by charge transfer from Sn to Ni for the catalysis. Selectivity to the desired furfuryl alcohol in all the intermetallic samples was high (\>97\%), but Ni1.35Sn had a relatively lower conversion than the other intermetallic compounds.

}, issn = {2050-7488}, doi = {10.1039/d4ta06383j}, author = {Cherevotan, Arjun and Singh, Ashutosh Kumar and Yadav, Anish and Maligal-Ganesh, Raghu V. and Raj, Jithu and Pulparambil, Anu and Goud, Devender and Vinod, Chathakudath P. and Peter, Sebastian C.} }