Exploring electrocatalytic stability and activity of unmodified and platinum-modified tungsten and niobium nitrides

Transition metal nitrides are interesting electrocatalytic support materials that have similar structure to their carbide counterparts while avoiding associated issues with carbonaceous overlayers resulting from carbide synthesis. This may allow for more intimate contact between the nitride substrate and metal-modifier to promote synergistic effects. In this work, tungsten nitride (WN) and niobium nitride (NbN) thin films were synthesized and evaluated for their stability across a wide range of potential-pH values. Low loadings of Pt were deposited on the nitride thin films and were evaluated for the hydrogen evolution reaction (HER) activity in acid and alkaline electrolytes. The observed activity trends correlate well with the hydrogen binding energies obtained from density functional theory (DFT) calculations. Pseudo-Pourbaix diagrams were generated for WN and NbN to aid in catalyst selection for other electrocatalytic reactions. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.