Atomic Uranium Modified Graphdiyne As Catalytic Material For Hydrogen Evolution Reaction: An Interfacial Descriptor Led Mechanistic Study

Catalysis operated on supported single metal atom is considered as one of the vital efforts for chemical and energy conversion. Despite the enormous amount of research on single transition metal (TM) enhanced graphdiyne (GDY) material, its modification with slightly depleted uranium remains unexplored. Herein, we conducted relativistic density functional theory (DFT) calculations for the accumulation of atomic uranium inside size suitable GDY pore. The stability of graphdiyne-uranium (GDY-U) is corroborated in terms of short U-C bond distances (2.34-2.44 angstrom), with local depletion of charge and greater U(5f)C(p) molecular orbital overlap. The magnificent structural and electronic properties of GDY-U system qualify it for the investigation of hydrogen evolution reaction (HER). The HER performance of all exposed sites, including central metal atom and four dissimilarly coordinated acetylenic carbons has been examined and compared with that of pure GDY. As the overall HER interfacial descriptor, free energy change of the intermediate state (DGH*) at the central metal surface of GDY-U was found to be most favorable (0.153 eV) amongst all sites and far superior to those of pure GDY. In addition to the uranium surface, the coordinated carbons also show improved HER activity, indicating the enhancement of the system upon metal insertion. The calculated DGH* of the GDY-U system here is comparable to some of the recently reported GDY-TM materials, suggesting that atomic uranium could be an exceptional alternative for applied common catalysts. (c) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.