@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 {49362, title = {Indazole-5-amine (AIA) as competing corrosion coating to Benzotriazole (BTAH) at the interface of Cu: A DFT and BOMD case study}, journal = {Computational and Theoretical Chemistry}, volume = {1239}, year = {2024}, month = {SEP}, pages = {114762}, type = {Article}, abstract = {

This study compares three organic compounds-benzotriazole (BTAH), imidazole (IM), and indazole-5-amine (AIA)-as corrosion inhibitors for copper substrates. Using Density Functional Theory (DFT) and Born-Oppenheimer Molecular Dynamics (BOMD) calculations, it identifies AIA as a promising and cost-effective alternative to the toxic BTAH. The adsorption strength on Cu(1 0 0) surfaces is ranked AIA\>BTAH\>IM for both neutral and deprotonated forms. These findings are supported by electronic parameter studies, including Bader charge analysis, density of states (DOS), charge density differences (CDD), and frontier molecular orbital analysis. AIA shows the best adsorption in a parallel orientation at the top site. Packing studies reveal that hydrogen bonding stabilizes the interaction energies within self-assembled AIA aggregates. Organometallic complexation studies reveal that deprotonated BTAH exhibits higher interaction energy with a single Cu atom compared to AIA when bonded through the carbon end, consistent with the findings from BOMD studies. However, on periodic Cu surfaces, AIA outperforms BTAH molecules as seen from adsorption energies. This investigation highlights AIA{\textquoteright}s potential as a superior and more economical corrosion inhibitor for copper.

}, keywords = {Adsorption, Born-Oppenheimer molecular dynamics, Corrosion inhibition, Density functional theory, Indazole derivatives}, issn = {2210-271X}, doi = {10.1016/j.comptc.2024.114762}, author = {Samal, Pragnya Paramita and Singh, Chandrodai Pratap and Tiwari, Shivani and Shah, Vaishali and Krishnamurty, Sailaja} } @article {50100, title = {Silico imine-based ligand engineering of CALF-20 for electrocatalytic ammonia production}, journal = {ACS Sustainable Chemistry \& Engineering}, volume = {14}, year = {2026}, month = {APR}, pages = {7217-7228}, type = {Article}, abstract = {

Electrocatalytic ammonia synthesis is emerging as a globally compelling, sustainable alternative to the Haber-Bosch process under ambient conditions. As a result, active-site engineering has taken center stage in the development of stable and effective electrocatalysts. In this work, we report how the introduction of an imine group in the ligand backbone of CALF-20, a Zn-based, moisture-stable MOF with high surface area, results in the formation of an N-4 macrocycle for transition-metal anchoring. PBE + D3 calculations, supported by spectroscopic, ab initio molecular dynamics, and electronic analyses, identify Fe-bound modified CALF-20 as the most stable configuration among the Mn-, Fe-, Co-, Ni-, Cu-, Ru-, Rh-, Ag-, and Au-anchored within the modified CALF-20 framework. Upon modification, the d-band center shifts from -5.08 to -4.44 eV in M-Fe-CALF-20. Adsorption studies confirm activation of both N-2 and NO2, reflected by bond elongation and red-shifted IR peaks. Mechanistic studies show that M-Fe-CALF-20 selectively facilitates NH3 formation, exhibiting PDS values of 0.69 and 0.62 eV for the NRR and NO2RR, respectively, while a competitive adsorption shows a clear preference over HER. Our study illustrates how functionalization tunes CALF-20 for dual application as an adsorbent and as an electrocatalyst for NH3 synthesis and storage.

}, keywords = {Adsorption, CALF-20 MOF, electrocatalysis, hydrogen evolution reaction, nitrogen oxide reductionreaction (NO2RR), nitrogen reductionreaction}, issn = {2168-0485}, doi = {10.1021/acssuschemeng.5c13550}, author = {Samudre, Nikhil S. and Samal, Pragnya Paramita and Krishnamurty, Sailaja} }