Oxygen-terminated BiXenes and derived single atom catalysts for the hydrogen evolution reaction

Advanced materials for active hydrogen evolution reaction (HER) electrocatalysts are central to the area of renewable energy. Here we report for the first time the application of two-dimensional (2D) oxygen terminated BiXenes as a new family of electrocatalysts for the HER in terms of the following electrochemical descriptors: Gibbs free energy of H adsorption (Delta G(H)), exchange current density and the required potential to achieve a 10 mA/cm(2) current density (polarization curve). The results reveal that oxygen terminated BiXenes have a high density of catalytically active sites, excellent electric conductivity, and maintain a high HER activity over a wide range of hydrogen coverages. Among these systems, Mo2CO2 are identified as exceptional HER catalyst in virtue of the comparable overpotential (107 mV) to that of Pt (58 mV). Most importantly, on the basis of a concept of "electron donation", depositing single transition metals (TM) on the surface of oxygen-terminated BiXenes to form single atom catalysts (SACs) and strain engineering, both of which are demonstrated to efficiently weaken the H bonding strength, are promising routes to enhance the HER activity of oxygen-terminated BiXenes. Our work is the first report of oxygen-terminated BiXenes, offering cost-effective alternatives to traditional Pt-based catalysts for advancing sustainable hydrogen evolution. (C) 2019 Elsevier Inc. All rights reserved.