Platinum and Gold Supported on Transition Metal Nitrides for Hydrogen Evolution in an Alkaline Electrolyte

• Published in: Energy & fuels Vol. 39; no. 11; pp. 5587 - 5593
• Main Authors: Nichols, Nathaniel N., Han, Xue, Kang, Sinwoo, Zhao, Hanjun, Kattel, Shyam, Chen, Jingguang G.
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 06.03.2025; American Chemical Society (ACS)
• Subjects: carbon dioxide; Catalysis and Kinetics; Catalysts; cost effectiveness; electrochemistry; electrolysis; electrolytes; energy; Evolution reactions; foil; GEOSCIENCES; Gibbs free energy; Gold; Granular materials; hydrogen; Hydrogen evolution reaction; hydrogen production; nitrides; Platinum; surface area; Thin films; Transition metal nitrides; X-ray absorption spectroscopy
• ISSN: 0887-0624; 1520-5029; 1520-5029
• DOI: 10.1021/acs.energyfuels.5c00198

As the urgency to reduce reliance on fossil fuels increases due to carbon dioxide emissions, hydrogen produced by renewably powered water electrolysis has emerged as a promising technology. Alkaline electrolyzers typically exhibit lower current densities than acidic electrolyzers due to the slow kinetics of the hydrogen evolution reaction (HER) under alkaline conditions. This work developed Pt- and Au-modified transition metal nitride (TMN) thin films for improving alkaline HER kinetics. One monolayer Pt–VN, Pt–Mo2N, and Pt–TiN were the most promising thin-film catalysts, with alkaline HER activity approaching that of a bulk Pt foil. Additionally, the Gibbs free energy of adsorbed hydrogen was identified as a useful descriptor for alkaline HER activity on TMN and TMN-supported catalysts and has the potential to guide future studies on TMN-based catalysts for enhancing alkaline HER. For practical applications, the thin-film catalysts were then extended to Pt- and Au-modified TMN powders for alkaline HER. Both 5 wt % Pt/TiN and 2 wt % Pt/TiN powders exhibited lower overpotentials at 5 mA/cm2 when normalized by the Pt electrochemical surface area than the commercial 5 wt % Pt/C benchmark, suggesting a Pt–TiN synergy that creates opportunities for more cost-effective alkaline HER cathodes. Moreover, 20 wt % Au/Mo2N also displayed an enhancement in HER activity when compared to the commercial 20 wt % Au/C benchmark.