Computational screening of defective BC3-supported single-atom catalysts for electrochemical CO2 reduction

The electrochemical CO2 reduction reaction (eCO2RR) driven by renewable electricity offers a green and sustainable technology for synthesizing chemicals and managing global carbon balance. However, developing electrocatalysts with high activity and selectivity for producing C1 products (CO, HCOOH, CH3OH, and CH4) remains a daunting task. In this study, we conducted comprehensive first-principles calculations to investigate the eCO2RR mechanism using B-defective BC3-supported transition metal single-atom catalysts (TM@BC3 SACs). Initially, we evaluated the thermodynamic and electrochemical stability of the designed 26 TM@BC3 SACs by calculating the binding energy and dissolution potential of the anchored TM atoms. Subsequently, the selectivity of the eCO2RR and hydrogen evolution reaction (HER) on stable SACs was determined by comparing the free energy change (ΔG) for the first protonation of CO2 with the ΔG of *H formation. The stability and selectivity screening processes enabled us to narrow down the pool of SACs to the 14 promising ones. Finally, volcano plots for the eCO2RR towards different C1 products were established by using the adsorption energy descriptors of key intermediates, and three SACs were predicted to exhibit high activity and selectivity. The limiting potentials (UL) for HCOOH production on Pd@BC3 and Ag@BC3 are -0.11 V and -0.14 V. CH4 is a preferred product on Re@BC3 with UL of -0.22 V. Elaborate electronic structure calculations elucidate that the activity and selectivity originate from the sufficient activation of the C-O bond and the strong orbital hybridization between crucial intermediates and metal atoms. The proposed catalyst screening criteria, constructed volcano plots and predicted SACs may provide a theoretical foundation for the development of computationally guided catalyst designs for electrochemical CO2 conversion to C1 products.

Copper Nanoparticles and Reduced Graphene Oxide as an Electrode Modifier for the Development of an Electrochemical Sensing Platform for Chloroquine Phosphate Determination

This study describes the use of copper nanoparticles (CuNPs) and reduced graphene oxide (rGO) as an electrode modifier for the determination of chloroquine phosphate (CQP). The synthetized rGO-CuNPs composite was morphologically characterized using scanning electron microscopy and electrochemically characterized using cyclic voltammetry. The parameters were optimized and the developed electrochemical sensor was applied in the determination of CQP using square-wave voltammetry (SWV). The analytical range for the determination of CQP was 0.5 to 110 μmol L^-1 (one of the highest linear ranges for CQP considering electrochemical sensors), with limits of detection and quantification of 0.23 and 0.78 μmol L^-1, respectively. Finally, the glassy carbon (GC) electrode modified with rGO-CuNPs was used for quantification of CQP in tap water; a study was carried out with interferents using SWV and obtained great results. The use of rGO-CuNP material as an electrode modifier was thus shown to be a good alternative for the development of low-cost devices for CQP analysis.

Density Functional Theory Interaction Study of a Polyethylene Glycol-Based Nanocomposite with Cephalexin Drug for the Elimination of Wound Infection

In this paper, density functional theory (DFT) simulations are used to evaluate the possible use of a graphene oxide-based poly(ethylene glycol) (GO/PEG) nanocomposite as a drug delivery substrate for cephalexin (CEX), an antibiotic drug employed to treat wound infection. First, the stable configuration of the PEGylated system was generated with a binding energy of -25.67 kcal/mol at 1.62 Å through Monte Carlo simulation and DFT calculation for a favorable adsorption site. The most stable configuration shows that PEG interacts with GO through hydrogen bonding of the oxygen atom on the hydroxyl group of PEG with the hydrogen atom of the carboxylic group on GO. Similarly, for the interaction of the CEX drug with the GO/PEG nanocomposite excipient system, the adsorption energies are computed after determining the optimal and thermodynamically favorable configuration. The nitrogen atom from the amine group of the drug binds with a hydrogen atom from the carboxylic group of the GO/PEG nanocomposite at 1.75 Å, with an adsorption energy of -36.17 kcal/mol, in the most stable drug-excipient system. Drug release for tissue regeneration at the predicted target cell is more rapid in moist conditions than in the gas phase. The solubility of the suggested drug in the aqueous media around the open wound is shown by the magnitude of the predicted solvation energy. The findings from this study theoretically validate the potential use of a GO/PEG nanocomposite for wound treatment application as a drug carrier for sustained release of the CEX drug.

Potential of B24O24 nanocluster for sensing and delivering chlormethine anticancer drug: a DFT study

In the present research, the adsorption and release of chlormethine (CM) drug on the B₂₄O₂₄ nanocage have been reported in the water media and gas phase at GGA/PBE/DNP computational level. The interaction between B₂₄O₂₄ nanocage and CM drug shows that adsorptions of the chlormethine on B₂₄O₂₄ nanocage for the most stable complexes are - 1.47 to - 1.36 eV in the gas phase and water media, respectively. The CM adsorption caused a notable change in the band gap (E_g) and work function (Φ) of the B₂₄O₂₄ nanocage in the studied complexes. The binding of chlormethine to B₂₄O₂₄ also significantly increased the polarity of the drug carrier, which is a desirable property for drug delivery in biological environments. CM drugs can be released from the nanocage in the presence of an external electric field along the X-axis direction. The present study results show that the B₂₄O₂₄ nanocage is a possible carrier for delivering chlormethine drugs.

Two-dimensionalcovalent triazine frameworks as superior nanocarriers for the delivery of thioguanine anti-cancer drugs: a periodic DFT study

This work aims to introduce a superior nanocarrier for thioguanine (TG) anti-cancer drug delivery, drug release, and cancer therapy through computational chemistry.