@article {47629, title = {Thermal stability of an endohedrally doped aluminum nanoclusters: a BOMD study}, journal = {Theoretical Chemistry Accounts}, volume = {140}, year = {2021}, month = {SEP}, pages = {132}, type = {Article}, abstract = {In this article, thermal stability of doped Al-13 nanoclusters has been systematically investigated within the framework of density functional theory (DFT). To explain thermal stability, simulations have been carried out over a temperature range from 300 to 1100 K using Born-Oppenheimer molecular dynamics (BOMD). The atomic displacements have been quantified by calculating delta(rms,) MSD and epsilon(pro.) The thermal stability of different clusters is explained using underlined electronic properties such as HOMO-LUMO, charges and bond length.}, keywords = {BOMD, Bond length fluctuations, Endohedral doping, Mean squared ionic displacements (MSD), Nanoclusters, Root mean squared}, issn = {1432-881X}, doi = {10.1007/s00214-021-02829-7}, author = {Singh, Chandrodai Pratap and Samal, Pragnya Paramita and Krishnamurty, Sailaja} } @article {47759, title = {Facile fabrication of nano silver phosphate on B-doped g-C3N4: an excellent p-n heterojunction photocatalyst towards water oxidation and Cr (VI) reduction}, journal = {Journal of Alloys and Compounds}, volume = {898}, year = {2022}, month = {MAR}, pages = {162853}, type = {Article}, abstract = {A photostable Ag3PO4/BCN type-II p-n heterojunction has been demonstrated by loading nano Ag3PO4 on B-doped g-C3N4 nanosheet (BCN). The photocatalysts were successfully characterized by various physicochemical techniques and their photocatalytic activities were tested towards the water oxidation reaction to produce oxygen and Cr (VI) reduction under visible light. The HRTEM confirms Ag3PO4 with a particle size of 15 nm has been deposited on BCN to construct a p-n heterojunction. The BCNS-50 absorbs more visible light in the solar spectrum as compared to other catalyst, demonstrating the ability to generate 587 mu mol h(-1)g(-1) O-2 and reduces 98\% of 20 ppm Cr (VI) solution in 1 h. The lower PL intensity as well as lower arc value in case of BCNS-50 suggests the maximum e-h separation and lower charge transfer resistance across the semiconductor/electrolyte interface. The BCN sheet provides a compact heterojunction where the oxidation peak of Ag3PO4 decreases gradually and disappear in case of BCNS-50 suggesting the enhance stability of Ag3PO4 in the heterojunction. BCNS-50 could able to produce -139 and 3087.5 mu A photocurrent both in cathodic and anodic direction which is approximately 7 and 2.4 folds higher as compared to nano Ag3PO4. The generation of photocurrent in both cathodic and anodic direction confirms the formation of p-n heterojunction which further supported by Mott-Schottky analysis. Furthermore the construction of the p-n heterojunction is verified via Mott-Schottky study. DFT calculation explains the contribution of various atomic orbital of Ag3PO4 and BCN towards the formation of hybrid orbital in the heterojunction and the path for charge delocalization between them. This work may provide a limelight and alternative pathway for enhanced photocatalytic performance on construction of the p-n heterojunction in a simple way. (C) 2021 Elsevier B.V. All rights reserved.}, keywords = {Cr (VI) reduction, Density functional theory, Interfacial zone, p-n heterojunction, Photocatalyst, Water oxidation}, issn = {0925-8388}, doi = {10.1016/j.jallcom.2021.162853}, author = {Sahoo, Mitarani and Babu, Pradeepta and Singh, Chandrodai Pratap and Krishnamurty, Sailaja and Parida, Kulamani} } @article {48084, title = {Mapping the finite-temperature behavior of conformations to their potential energy barriers: case studies on Si6B and Si5B clusters}, journal = {ACS Omega}, volume = {7}, year = {2022}, month = {FEB }, pages = {6167-6173}, type = {Article}, abstract = {

Dynamical simulations of molecules and materials have been the route to understand the rearrangement of atoms within them at different temperatures. Born-Oppenheimer molecular dynamical simulations have further helped to comprehend the reaction dynamics at various finite temperatures. We take a case study of Si6B and Si5B clusters and demonstrate that their finite-temperature behavior is rather mapped to the potential energy surface. The study further brings forth the fact that an accurate description of the dynamics is rather coupled with the accuracy of the method in defining the potential energy surface. A more precise potential energy surface generated through the coupled cluster method is finally used to identify the most accurate description of the potential energy surface and the interconnected finite-temperature behavior.

}, issn = {2470-1343}, doi = {10.1021/acsomega.1c06654}, author = {Maneri, Asma H. and Singh, Chandrodai Pratap and Kumar, Ravi and Maibam, Ashakiran and Krishnamurty, Sailaja} } @article {48368, title = {Structure-property insights into chiral thiophene copolymers by direct heteroarylation polymerization}, journal = {European Polymer Journal}, volume = {181}, year = {2022}, month = {DEC }, pages = {111676}, type = {Article}, abstract = {

Chiral thiophene copolymers with fluorene as co monomer are designed having N-Boc-L-glutamic acid-1-tert-butyl ester as a chiral substituent located either on the thiophene unit or the fluorene unit with varying spacer length. The atom-economic direct heteroarylation polymerization (DHAP) method is utilized for the polymerization. Gibb{\textquoteright}s free energy (delta G) for polymerization determined using DFT calculations indicate difficulty in achieving high molar mass when the bulky chiral substituents are attached through short spacer to the backbone. The experimental observations are in agreement with the theoretical calculations with no polymer-ization or very low molar mass sticky compounds obtained for reactions with predicted + \& UDelta;G values. Structure -property relationship are compared for two chiral polymers -P4 and P5 having the chiral substitution on thiophene and fluorene units respectively. No CD signal is observed in THF-a good solvent where the polymers are molecularly dissolved. Intense bisignated CD signal is observed for both polymers upon addition of methanol - a poor solvent, to their THF solution. The bisignate CD signal with maxima at lower wavelength and inflection point associated with the pi-pi* absorption band is characteristic of exciton coupling between polymer chains in a left handed helical orientation. Small differences are observed in the intensity of the CD signal for the polymers P4 and P5 highlighting the impact of steric hindrance of bulky pendant groups on polymer conformation. DHAP is an atom economic polymerization procedure that can be gainfully utilized for developing chiral conjugated polymers.

}, keywords = {chiral, DFT, Direct heteroarylation polymerization, Gibb?s free energy, Steric Hindrance}, issn = {0014-3057}, doi = {10.1016/j.eurpolymj.2022.111676}, author = {Nikam, Shrikant B. and Singh, Chandrodai Pratap and Krishnamurty, Sailaja and Asha, S. K.} } @article {48013, title = {Synergetic storage of ammonia over Al quantum dots embedded graphene sheets: a first principles perspective}, journal = {International Journal of Hydrogen Energy}, volume = {47}, year = {2022}, month = {OCT }, pages = {36873-36885}, type = {Article}, abstract = {

In view of the increasing energy demand and global warming, it is imperative to search for a renewable and environmental friendly fuel in lieu of non-renewable energy resources. Hydrogen stands out to be the best fuel as both, renewable and clean. Concerning the use of hydrogen as a fuel, its production as well as storage are current global challenges being worked on. In this article, a density functional theory based study is performed to identify the potential of supported Al cluster cages for ammonia storage. In this context, initially, stability of pristine and doped aluminum nanoclusters anchored on graphene sheet is evaluated following which thus supported stable nanoclusters are studied for the adsorption of NH3 to identify their storage capacity. For both, complexes and NH3 adsorbed complexes, Density of States (DOS), Charge Density Difference (CDD) and Bader charge analysis is done to understand their electronic properties.(c) 2022 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

}, keywords = {Aluminum nanoclusters, Defective graphene, Endohedral doping, NH 3 adsorption}, issn = {0360-3199}, doi = {10.1016/j.ijhydene.2022.08.268}, author = {Singh, Chandrodai Pratap and Krishnamurty, Sailaja} } @article {48268, title = {Chemically modified graphene sheets as potential sensors for organophosphate compounds(pesticide): A DFT study}, journal = {Applied Surface Science}, volume = {619}, year = {2023}, month = {MAY}, pages = {156745}, type = {Article}, abstract = {

Owing to the extensive use of pesticides in agriculture and the threat posed to the environment and humankind, attention is drawn toward the need for its remediation from various sources, in particular from water. The adsorption characteristics of hydrophobic graphene and its BN doped counterparts are evaluated using DFT methodology, to assess their sensing potential towards notable pesticide molecules (Organophosphate pesticides (OPs) such as chlorpyriphos, parathion, methyl-parathion, and fenitrothion). To accomplish this, various elec-tronic properties such as band structure, DOS, Bader charge analysis, and CDD have been calculated. Interest-ingly, exothermic interactions (-0.1 eV to-2 eV) have been noted for all the OPs with NB doped single vacancy defect induced graphene surfaces. With an exception of FTN, all the other OPs showed significant changes in the electronic properties of surfaces as apparent from the change in band gap and nature of the band from indirect to direct. The appreciable adsorption energy, higher charge transfer, and notable variation in the band gap are the decisive factors behind the strong interaction exhibited by NB doped surfaces especially dg-(NB-2)2 (except FTN). These findings demonstrate the suitability of NB doped single vacancy defect induced graphene sheets for the detection of the studied OPs.

}, keywords = {Adsorption, BN doped graphene surfaces, Charge density difference, Density functional theory, Organophosphate pesticides}, issn = {0169-4332}, doi = {10.1016/j.apsusc.2023.156745}, author = {Shivankar, Bhavana R. and Singh, Chandrodai Pratap and Krishnamurty, Sailaja} } @article {48445, title = {Expounding lemonal terpenoids as corrosion inhibitors for copper using DFT based calculations}, journal = {Applied Surface Science}, volume = {614}, year = {2023}, month = {MAR}, pages = {156066}, type = {Article}, abstract = {

The most important bottleneck in identifying an innovative and yet viable corrosion inhibitor for copper surfaces is discerning the chemical interactions at the interface of adsorbate and adsorbent. The present work, primarily, discerns the interface chemistry of green corrosion inhibitors, viz., lemonal terpenoids, with the copper surfaces for the first time. The interface chemistry is evaluated for distinct facets of copper, modelled by periodic surfaces to finite sized aggregates, with two stereoisomers viz., citral and neral through density functional calculations. The adsorption/ interaction properties between the surface and the corrosion inhibiting molecule are analysed through the electronic properties such as density of states, charge density difference plots and Bader charges where in distinct bonding mechanisms are identified as a function of varying facets. Apart from the adsorption properties, molecular packing properties are of paramount importance towards the design of an efficient corrosion inhibitor for a surface. Hence, we also analyse the intermolecular stacking energies between the inhibitors when packed among themselves in vacuum and when adhered on to metal surfaces. The studies bring forth an understanding that lemon terpenoids are highly potential corrosion inhibitors for copper surfaces, particularly, for Cu (110) surfaces both in neutral and protonated form.

}, keywords = {Copper surface, Density Functional Theory (DFT), Green corrosion inhibitors, Interface chemistry, Lemonal terpenoids, Molecular stacking}, issn = {0169-4332}, doi = {10.1016/j.apsusc.2022.156066}, author = {Samal, Pragnya Paramita and Singh, Chandrodai Pratap and Krishnamurty, Sailaja} } @article {48259, title = {Investigation of the effect of zeolite supports and the role of W-species for one-pot catalytic conversion of cellulose to ethylene glycol: theoretical \& experimental studies.}, journal = {Chemistry-An Asian Journal}, volume = {18}, year = {2023}, month = {FEB }, type = {Article}, abstract = {

Endeavors were made to study the influence of various zeolite (HY, NaY, NaZSM-5 and HZSM-5) supports with (Al)-Ni-W metal combination catalysts for the ethylene glycol (EG) production, selectively from cellulose. From the experimental results ZSM-5 (NaZSM-5/73.3\% \& HZSM-5/67.7\%) support is superior over HY \& NaY support in selective EG production from cellulose. It was understood that W- species with oxygen vacancies (WO3-x, XPS analysis) plays an important role in producing the glycolaldehyde (GA) intermediate (via C-C cleavages), which on hydrogenation over Ni- sites selectively produce EG. Further, the studies based on the Density Functional Theory (DFT) were conducted to substantiate the involvement of the WO3-x species in the reaction. The adsorption energies and structural changes establish that the C-2-C-3 bond of the glucose elongates and thereby activates on adsorbing to WO3-x sites supporting the formation of GA. Activation of GA on Ni- sites is distinguished by an increase of 0.1 angstrom in C=O bond length, which facilitates the hydrogenation of C=O resulting in EG. The reaction pathway is explained through an analysis of CDD and DOS.

}, keywords = {Cellulose hydrogenolysis, DFT studies, ethylene glycol, zeolites}, issn = {1861-4728}, doi = {10.1002/asia.202201202}, author = {Sreekantan, Sreejith and Singh, Chandrodai Pratap and Krishnamurty, Sailaja and Marimuthu, Banu} } @article {48456, title = {Understanding the thermal stability of a 3d, 4d, and 5d element doped aluminium nanocluster through BOMD simulations}, journal = {Molecular Simulation}, volume = {49}, year = {2023}, month = {FEB}, pages = {245-250}, type = {Article}, abstract = {

Endohedrally doped atomic clusters have generated considerable interest among computational chemists on account of their tunable chemical properties that mimic a super atom. Such endohedrally doped clusters have also been experimentally realised in the more recent past. The present work explores the practical existence of 3d, 4d and 5d doped aluminium clusters, more specifically doped Al13 cluster, by evaluating systematically their structural stability through the first principle molecular dynamical simulations. Born-Oppenheimer Molecular Dynamics (BOMD) simulations have been carried out on Al12X atomic clusters where X = Ti, V, Fe, Co, Ni, Cu, Zn, Y, Mo, Ru, Rh and W are in endohedral position. The thermal stability of such endohedrally doped clusters is quantified through parameters such as delta(rms), MSD and is an element of(pro). Electronic structure calculations reveal that endohedral doping of only Rh, Cu and Zn is preferred in the Al-13 cluster. Other dopants prefer to remain on the surface positions. However, finite temperature calculations reveal that the Al12Zn cluster undergoes surface modifications from 300K leading to a distorted icosahedral structure. Al12Cu cluster in quartet spin state is the only thermally stable cluster with Cu remaining in the endohedral position and structure retaining icosahedral confirmation till 700K.

}, keywords = {Al-13 atomic cluster, BOMD simulations, DFT, Endohedral doping, super atom}, issn = {0892-7022}, doi = {10.1080/08927022.2022.2153151}, author = {Samudre, Nikhil S. and Singh, Chandrodai Pratap and Krishnamurty, Sailaja} }