Computational Screening of Electrocatalytic Activity of Transition Metal-Doped CdS Nanotubes for Water Splitting

Abstract

Exploring novel catalyst materials for water-splitting reaction is far-reaching in the current research scenario. CdS-derived nanostructures have been identified as potential catalysts for water splitting for decades. Realizing the competence of transition-metal (TM) doping in the desirable tuning of the properties of nanostructures, we have studied the catalytic activity of late TM (TM = Fe, Co, Ni, Cu, Ru, Rh, Pd, Ag, Os, Ir, Pt, and Au)-doped CdS nanotubes (TM@CdS NTs) for both oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). Systematic screening of stability as well as activity among the doped NT structures is carried out, and the results are compared with pristine CdS NT and bulk CdS. The doping of TMs is found to be accompanied by an enhancement of impurity d states near the Fermi level, suggesting an efficient electrocatalytic activity. Majority of TM-doped structures are associated with significant stability and are observed to improve both OER and HER activities. Activity analysis places Pd@CdS and Ru@CdS as optimal catalysts for OER and HER, respectively, with the lowest overpotential, outperforming pristine CdS NTs as well as bulk CdS. The origin of the activity trend is attributed to the differences in the interaction with the reaction intermediates across the series of doped NT structures. A complete scrutiny of energetics of elementary reactions for all TM@CdS NT structures is provided, and an activity plot is constructed to have a correlation between overpotential and adsorption energetics. © Copyright 2019 American Chemical Society.