Understanding interactions of biomolecules with nanomaterials at the molecular level is crucial to design new materials for practical use. In the present study, adsorption of three distinct types of amino acids, namely, valine, arginine and aspartic acid, over the surface of structurally analogous but chemically different graphene and BN nanosheets has been explored within the formalism of DFT. The explicit dispersion correction incorporated in the computational methodology improves the accuracy of the results by accounting for long range van der Waals interactions and is essential for agreement with experimental values. The real biological environment has been mimicked by re-optimizing all the model structures in an aqueous medium. The study provides ample evidence in terms of adsorption energy, solvation energy, separation distance and charge analysis to conclude that both the nano-surfaces adsorb the amino acids with release of energy and there are no bonded interactions between the two. The polarity of the BN nanosheet provides it an edge over the graphene surface to have more affinity towards amino acids.

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Reduction of dinitrogen to ammonia under ambient conditions is a long‐standing challenge. The few metal‐based catalysts proposed have conspicuous disadvantages such as high cost, high energy consumption, and being hazardous to the environment. Single‐atom catalysis has emerged as a new frontier in heterogeneous catalysis and metal atoms atomically dispersed on supports receive more and more attention owing to rapid advances in synthetic methodologies and computational modeling. Herein, we propose metal atoms embedded in divacant graphene as a catalyst for N2 fixation based on density functional calculations. We systematically investigate the potential of using transition metal like Cr, Mn, Fe, Mo and Ru as catalysts and our study reveals that Cr embedded in graphene exhibit good catalytic activity for N2 fixation. The synergy between the metal atoms and graphene surface provides a stable support to the metal center that has a high spin density to promote adsorption of N2 and activation of its N≡N triple bond. Our study deciphers the mechanism of conversion of N2 to ammonia following two possible reaction pathways, distal and enzymatic routes, via sequential protonation and reduction of activated N2. The study provides a rational framework for conversion of dinitrogen to ammonia using single atom catalyst.

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