02518nas a2200145 4500008004100000245013200041210006900173260000900242300001600251490000600267520191800273100002402191700002602215856013102241 2019 eng d00aMolecular and dissociative adsorption of oxygen on au-pd bimetallic clusters: role of composition and spin state of the cluster0 aMolecular and dissociative adsorption of oxygen on aupd bimetall cJULY a12687-126950 v43 a

Utilization of molecular oxygen as an oxidizing agent in industrially important reactions is the ultimate goal to design environmentally benign processes under ambient conditions. However, the high thermal stability and a large O-O dissociation barrier in O-2 molecule pose a great challenge toward its successful application in the oxidative chemistry. To achieve this goal, different catalysts based on monometallic and bimetallic clusters have been developed over the years to promote binding and dissociation of molecular oxygen. The successful design of efficient metal cluster catalysis needs an in-depth knowledge of synergistic effects between different metal atoms and intrinsic catalytic mechanisms for O-2 adsorption and dissociation. Here, we present a systematic theoretical investigation of reaction pathways for O-2 adsorption and dissociation on Au-8, Pd-8, and Au8-nPdn (n = 1-7) nanoclusters in different spin states. The density functional calculations point out that the O-2 dissociation barriers can be significantly reduced with the help of certain bimetallic clusters along specific spin channels. Our results particularly indicate that Au5Pd3 and Au1Pd7 show very large O-2 binding energies of 1.76 and 1.69 eV, respectively. The enhanced O-2 binding subsequently leads to low activation barriers of 0.98 and 1.19 eV along the doublet and quartet spin channels, respectively, without the involvement of any spin flip-over for O-2 dissociation. Furthermore, the computed O-2 dissociation barriers are significantly low as compared to the already reported barriers (1.95-3.65 eV) on monometallic and bimetallic Au-Ag clusters. The results provide key mechanistic insights into the interaction and dissociation of molecular oxygen with Au-Pd clusters, which can prove informative for the design of efficient catalysts for oxidative chemistry involving molecular oxygen as a reactant.

1 aDar, Manzoor, Ahmad1 aKrishnamurty, Sailaja uhttps://library.ncl.res.in/content/molecular-and-dissociative-adsorption-oxygen-au-pd-bimetallic-clusters-role-composition-and01232nas a2200169 4500008004100000022001400041245012300055210006900178260000900247300001600256490000700272520058700279100001700866700002600883700002400909856012900933 2020 eng d a1463-907600aSurface functionalization: an efficient alternative for promoting the catalytic activity of closed shell gold clusters0 aSurface functionalization an efficient alternative for promoting cOCT  a23351-233590 v223 a

{Surface functionalization through adsorption of ligands or non-metal atoms is considered to be an interesting and viable approach for tuning the physicochemical properties of gold clusters. Highly stable and magic numbered electronic configurations of thiolate protected gold clusters such as Au-25(SR)(18), Au-38(SR)(24)etc. with intriguing properties are the direct manifestation of the rich chemistry of the Au-S interface. The present investigation discerns the CO oxidation activity of structurally well characterized sulphur functionalized gold cluster anions AumS4-

1 aJoshi, Krati1 aKrishnamurty, Sailaja1 aDar, Manzoor, Ahmad uhttps://library.ncl.res.in/content/surface-functionalization-efficient-alternative-promoting-catalytic-activity-closed-shell01430nas a2200133 4500008004100000245009700041210006900138260000800207520088800215100002201103700002601125700002401151856012101175 2021 eng d00aElectrocatalytic nitrogen reduction directed through the p-band center of boron on BSAC@Mo2C0 aElectrocatalytic nitrogen reduction directed through the pband c cNOV3 aGreener modes of ammonia synthesis via the electrocatalytic route have been investigated on pristine and defective Mo2C based monolayers anchored with metal-free boron atom catalysts. Boron single atom catalysts (SACs) on the defective Mo2C monolayer has been found to activate N2 strongly with an adsorption energy of −1.92 eV and reduce it to NH3 efficiently with a significantly low overpotential of 0.41 eV. The exothermic adsorption of N2 and low overpotential for the nitrogen reduction reduction (NRR) appertain to the p-band center of the boron atom catalyst and charge transfer between the adsorbed N2 and the catalyst, respectively. This work brings forth the correlation between electron occupancy on the boron center and NRR catalytic efficiency on a metal-free SACs@Mo2C monolayer couple, thereby serving as a lead in designing metal free electrocatalysts for the NRR.1 aMaibam, Ashakiran1 aKrishnamurty, Sailaja1 aDar, Manzoor, Ahmad uhttps://library.ncl.res.in/content/electrocatalytic-nitrogen-reduction-directed-through-p-band-center-boron-bsacmo2c01888nas a2200181 4500008004100000022001400041245015300055210006900208260000900277300001400286490000700300520117800307100001601485700002201501700002901523700002401552856013001576 2022 eng d a1144-054600aExploring the structure and electronic properties of germanium doped boron clusters using density functional theory based global optimization method0 aExploring the structure and electronic properties of germanium d cMAR  a6244-62540 v463 a

Density functional theory calculations in the framework of B3LYP, TPSS and M06-L were carried out to investigate the effect of single and double germanium atom doping on the geometric structure and electronic properties of boron clusters with 10 to 20 atoms. Global minima of GeBn and Ge2Bn (n = 10-20) were first obtained through Crystal Structure Analysis by the Particle Swarm Optimization method and then subsequently optimized using meta-generalized gradient approximation, hybrid and local functionals. It is found that the lowest energy structures of GeBn and Ge2Bn clusters exhibit planar, quasi-planar, semi-cage, bowl, and double ring topologies. Like BnSi clusters, the results reveal that the germanium atom prefers the peripheral regions of the B-n framework contrary to transition metal doped boron clusters. Furthermore, the calculated electronic properties such as the average binding energy and second order difference in binding energy indicate GeB20 and Ge2B16 to be the most stable clusters. Molecular orbital and adaptive natural density partitioning analyses were carried out to understand the extra stability of GeB20 and Ge2B16 clusters.

1 aAnis, Insha1 aDar, Mohd, Saleem1 aRather, Ghulam, Mohammad1 aDar, Manzoor, Ahmad uhttps://library.ncl.res.in/content/exploring-structure-and-electronic-properties-germanium-doped-boron-clusters-using-density02821nas a2200313 4500008004100000245018800041210006900229260000800298300001600306490000600322520168400328653002302012653001802035653003302053653003202086653002002118653003302138653002202171100002002193700001602213700001702229700001702246700002002263700001902283700002402302700002602326700002402352856013102376 2022 eng d00aFirst-principles investigation of the electrocatalytic reduction of CO2 on zirconium-based single-, double-, and triple-atom catalysts anchored on a graphitic carbon nitride monolayer0 aFirstprinciples investigation of the electrocatalytic reduction  cOCT a15409-154170 v53 a

Conversion of carbon dioxide (CO2) with the help of an appropriate electrocatalyst with high stability, low onset potential, and exceptional selectivity is still one of the great tasks in the electrocatalytic reduction of CO2 to valuable chemicals. Herein, by means of systematic first-principles simulations, we investigate the CO2 reduction reaction (CO2RR) activity of zirconium-based single-, double-, and triple-atom (Zrn@C2N; n = 1-3) catalysts anchored on a graphitic carbon-nitride monolayer. In tune with the Sabatier principle, our results reveal that a moderate CO2 binding is vital for a low onset potential for the CO2RR. Consequently, based on rigorous free energy calculations, the Zr-based single-atom catalyst (SAC) is found to be most effective to convert CO2 to valuable products such as HCOOH and CH3OH. It is worth noting that CO2 reduction to HCOOH is spontaneous via the *HCOO intermediate on Zr1@C2N and involves a low onset potential of -0.23 V with respect to the reversible hydrogen electrode from the *COOH intermediate. Among all the catalysts evaluated computationally, the Zr SAC further reveals the lowest onset potential of -0.89 V for CH3OH formation. The results show that the Zr-based catalysts especially Zr1@C2N are found to effectively suppress the competitive hydrogen evolution reaction and promote the CO2RR. Moreover, all three catalysts exhibit high kinetic and thermal stability with negligible distortion due to which their structures can be retained very well up to 600 K. Thus, the current work may provide effective catalyst-design strategies for enhancing the electrocatalytic CO2RR performance of Zr-based materials.

10aC1 and C2 products10aCO2 reduction10afirst-principles simulations10ahydrogen evolution reaction10aonset potential10asingle-atom catalysts (SACs)10aZrn@C2N catalysts1 aHassan, Afshana1 aAnis, Insha1 aShafi, Sadaf1 aAssad, Assif1 aRasool, Anjumun1 aKhanam, Romana1 aBhat, Gulzar, Ahmad1 aKrishnamurty, Sailaja1 aDar, Manzoor, Ahmad uhttps://library.ncl.res.in/content/first-principles-investigation-electrocatalytic-reduction-co2-zirconium-based-single-double01908nas a2200193 4500008004100000022001400041245009800055210006900153260000900222300001600231490000600247520122300253100001601476700002201492700002401514700002901538700002401567856012301591 2022 eng d a2470-134300aProbing the site-specific reactivity and catalytic activity of Ag-n (n=15-20) silver clusters0 aProbing the sitespecific reactivity and catalytic activity of Ag cJUN  a19687-196930 v73 a

Density functional theory calculations within the framework of generalized gradient approximation (GGA), meta-GGA, and local functionals were carried out to investigate the reactivity and catalytic activity of Ag-n (n = 15-20) clusters. Our results reveal that all the Ag-n dusters in this size range, except Ag-20, adsorb O-2 preferably in the bridged mode with enhanced binding energy as compared to the atop mode. The O-2 binding energies range from 0.77 to 0.29 in the bridged mode and from 0.36 to 0.15 eV in the atop mode of O-2 adsorption. The strong binding in the case of the bridged mode of O-2 adsorption is also reflected in the increase in O-O bond distance. Natural bond orbital charge analysis and vibrational frequency calculations reveal that enhanced charge transfer occurs to the O-2 molecule and there is significant red shift in the stretching frequency of O-O bond in the case of the bridged mode of O-2 adsorption on the clusters, thereby confirming the above results. Moreover, the simulated CO oxidation reaction pathways show that the oxidation of the CO molecule is highly facile on Ag-16 and Ag-18 clusters involving small kinetic barriers and higher heats toward CO2 formation.

1 aAnis, Insha1 aDar, Mohd, Saleem1 aBhat, Gulzar, Ahmad1 aRather, Ghulam, Mohammad1 aDar, Manzoor, Ahmad uhttps://library.ncl.res.in/content/probing-site-specific-reactivity-and-catalytic-activity-ag-n-n15-20-silver-clusters02241nas a2200217 4500008004100000022001400041245016500055210006900220260000900289300001200298490000700310520143100317100002001748700001601768700001701784700002201801700002001823700002601843700002401869856013001893 2022 eng d a2044-475300aTantalum based single, double, and triple atom catalysts supported on g-C2N monolayer for effective nitrogen reduction reaction: a comparative DFT investigation0 aTantalum based single double and triple atom catalysts supported cJAN  a310-3190 v123 aDesign of efficient and low cost electrocatalysts for the reduction of N-2 molecule to NH3 in a green manner remains a great challenge in the 21st century. Herein, we have used density functional theory based first principle simulations to systematically investigate the nitrogen reduction reaction (NRR) ability of single, double, and triple Ta-atom catalysts anchored to C2N monolayer. Our results demonstrate that the single and triple Ta-atom catalysts anchored to C2N monolayer act as superior catalysts for the NRR via alternating and distal pathways as compared to the Ru(0001) stepped surface. In particular, the triple Ta-atom catalyst anchored to C2N shows enhanced NRR performance with a limiting potential of -0.72 V which is comparable to the experimentally reported Ru based single atom catalyst. Further, all the three catalysts were found to be highly selective for NRR with an enhanced ability to suppress the competitive hydrogen evolution reaction. Electronic structure analysis revealed that the enhanced ability of Ta-3@C2N catalyst to effectively capture and reduce N-2 molecule could be attributed to the built up of localized d states near the fermi level, thereby aiding in strong electron transfer into the antibonding orbitals of N-2. Thus, our findings propose a highly active catalyst for the NRR with an emphasis on the importance of triple atom-based catalysts for electrocatalytic applications.1 aRasool, Anjumun1 aAnis, Insha1 aDixit, Mudit1 aMaibam, Ashakiran1 aHassan, Afshana1 aKrishnamurty, Sailaja1 aDar, Manzoor, Ahmad uhttps://library.ncl.res.in/content/tantalum-based-single-double-and-triple-atom-catalysts-supported-g-c2n-monolayer-effective02052nas a2200265 4500008004100000022001400041245015000055210006900205260000900274300001400283490000700297520102600304653002401330653003601354653005501390653003801445653003001483653002001513100002501533700002501558700002401583700002701607700002601634856012601660 2024 eng d a0360-319900aComputational identification of most potent atom pair catalysts for electrocatalytic nitrogen reduction reaction over hydrogen evolution reaction0 aComputational identification of most potent atom pair catalysts  cMAR  a1345-13580 v583 a

Robust electrocatalytic atom pair compositions (APCs) where Nitrogen Reduction Reaction (NRR) is more enhanced over competing Hydrogen Evolution Reaction (HER) is searched for using computational studies based on Density Functional Theory based methods. Atomic pairs are anchored on mechanically and thermally stable graphene surfaces. A wide range of transition metal based atom pair compositions from 3d, 4d, and 5d groups are systematically investigated for reduction of dinitrogen molecule with lower reduction barrier as compared to HER. APR compositions of Ni-Rh with an overall limiting potential of -0.22 V, Fe-W with an overall limiting potential of -0.26 V and Co-Pt with an overall limiting potential of -0.28 V are identified as the most potent atomic pairs for enhanced nitrogen reduction reaction over the HER. Finally, the performance of most potent composition, viz., Ni-Rh is validated to be consistent with respect to their thermodynamic stability and performance within the solvent effects.

10aAtom pair catalysts10aDensity Functional Theory (DFT)10aElectrochemical nitrogen reduction reaction (eNRR)10ahydrogen evolution reaction (HER)10aIR stretching frequencies10aN-N bond length1 aVerma, Tushar, Singh1 aDar, Afshana, Hassan1 aDar, Manzoor, Ahmad1 aSelvaraj, Kaliaperumal1 aKrishnamurty, Sailaja uhttps://library.ncl.res.in/content/computational-identification-most-potent-atom-pair-catalysts-electrocatalytic-nitrogen02302nas a2200229 4500008004100000022001400041245012500055210006900180260000800249490000700257520147900264653001901743653002201762653002001784653003601804653002301840100001701863700002601880700002401906700001701930856012501947 2024 eng d a1439-423500aSize and morphology dependent activity of Cu clusters for CO2 activation and reduction: a first principles investigation0 aSize and morphology dependent activity of Cu clusters for CO2 ac cDEC0 v253 a

Various Cu-based materials in diverse forms have been investigated as efficient catalysts for electrochemical reduction of CO2; however, they suffer from issues such as higher over potential and poor selectivity. The activity and selectivity of CO2 electro reduction have been shown to change significantly when the surface morphology (steps, kinks, and edges) of these catalysts is altered. In light of this, size and morphology dependent activity of selected copper clusters, Cun (n=2-20) have been evaluated for the activation and reduction of CO2 molecule. The phase-space of these copper clusters is rich in conformations of distinct morphologies starting from planar, 2D geometries to prolate-shaped geometries and also high-symmetry structures. The binding efficiency and the activation of CO2 are highest for medium sized clusters (n=9-17) with prolate-morphologies as compared to small or larger sized CunCO(2) clusters that are existing mainly as planar (triangular, tetragonal etc.) or highly-symmetric geometries (icosahedron, capped-icosahedron etc.), respectively. The best performing (prolate-shaped) CunCO2 conformations are quite fluxional and also they are thermally stable, as demonstrated by the molecular dynamics simulations. Furthermore, on these CunCO(2) conformations, the step-by-step hydrogenation pathways of CO2 to produce value-added products like methanol, formic acid, and methane are exceptionally favorable and energy-efficient.

10aCO2 activation10aCO2 hydrogenation10aCopper clusters10aDensity Functional Theory (DFT)10amolecular dynamics1 aAmin, Seerat1 aKrishnamurty, Sailaja1 aDar, Manzoor, Ahmad1 aJoshi, Krati uhttps://library.ncl.res.in/content/size-and-morphology-dependent-activity-cu-clusters-co2-activation-and-reduction-first03165nas a2200157 4500008004100000022001400041245011300055210006900168260000800237490000600245520256000251100001702811700002602828700002402854856012902878 2025 eng d a2398-490200aBoosting the CO2 reduction activity of Cu double-atom catalysts through coordination environment engineering0 aBoosting the CO2 reduction activity of Cu doubleatom catalysts t cOCT0 v93 a

Double-atom catalysts (DACs) offer a reasonable and scalable route towards carbon neutrality owing to their efficient catalytic features. However, the challenges associated with the flexibility of their coordination structure usually restrict their full potential as efficient catalysts. Herein, we comprehensively examined the impact of coordination environment regulation on the CO2R activity of Cu2-DACs supported on C, N, or B co-doped graphene using ab initio simulations. We highlighted the marked role of the local coordination sphere of Cu2-DACs in modulating their structural stability and charge transfer characteristics, thereby regulating the adsorption of CO2 and various reaction characteristics. Notably, boron- and carbon-coordinated Cu2 centres (Cu2-BxCy) resulted in remarkably strong CO2 adsorption (-0.65 to -2.31 eV), attributed to their amplified electronic interactions with the CO2 molecule. The weak CO2 binding observed on the carbon-nitrogen- and nitrogen-boron-coordinated Cu2 centres (Cu2-NxCy and Cu2-NxBy) further highlighted the role of the coordination environment in facilitating the versatile binding modes of the key reaction species. The varying CO2 interactions in these systems were further comprehended and supported by a multilevel descriptor () combining both geometric and electronic parameters. This descriptor closely mirrored the DFT results, thereby accentuating its effectiveness as a predictive tool to perfectly model the CO2 interactions on these catalysts. Moreover, the dynamic behaviour in the adsorption modes led to partial breakdown of the conventional linear scaling relations between the key CO2 reduction intermediates (*COOH, *CO, and *HCO). Among the numerous types of investigated electrocatalysts, Cu2-B5C1 emerged as a highly active and selective catalyst for methanol production, with a remarkably low limiting potential of -0.54 V, surpassing the performance of several reported Cu-based systems. Besides, our findings underscored the often-overlooked yet crucial role of explicit solvation, which significantly altered both the potential-determining step and product selectivity. These outcomes emphasized the necessity of including solvation effects in realistic electrochemical modelling. Collectively, this study provides a critical mechanistic insight into better understanding the coordination effect on the CO2R and a robust design strategy for next-generation Cu-based DACs, guiding the development of highly efficient and selective catalysts for CO2 electroreduction.

1 aAmin, Seerat1 aKrishnamurty, Sailaja1 aDar, Manzoor, Ahmad uhttps://library.ncl.res.in/content/boosting-co2-reduction-activity-cu-double-atom-catalysts-through-coordination-environment