(9c) The Role of Bulk Intercalation in the Electrocatalytic Hydrogen Evolution Reaction on Tungsten Oxides

Metal oxides are attracting increased attention as potential electrocatalysts due to their low cost, activity, and selectivity. However, these materials can undergo significant chemical changes under reaction conditions, presenting challenges in their characterization and optimization of catalytic behavior. In this talk, I will discuss how first principles calculations reveal the impact of bulk hydrogen intercalation on the catalytic behavior of tungsten oxides^1,2. Hydrogen insertion in the bulk of the oxide modifies the Lewis acid-base properties at the surface and the overall electronic structure of the catalyst (observed as a semiconductor-to-metal transition). This modification results in converting the non-intercalated and inactive oxide to a highly active hydrogen evolution electrocatalyst. Our results explain a series of electrocatalytic hydrogen evolution experiments on tungsten oxides, identify the degree of intercalation (i.e, x in H_xWO₃) responsible for hydrogen evolution and demonstrate the participation of bulk hydrogen in the reactions.

1. The Sensitivity of Metal Oxide Electrocatalysis to Bulk Hydrogen Intercalation: Hydrogen Evolution on Tungsten Oxide, Miu E.V., McKone J.R. and Mpourmpakis G., J. Amer. Chem. Soc. 144, 14, 6420–6433 (2022)
2. Participation of Electrochemically Inserted Protons in the Hydrogen Evolution Reaction on Tungsten Oxides, Spencer M.A., Holzapfel N.P., You K.-E., Mpourmpakis G. and Augustyn V. Chemical Science, 15, 5385-5402 (2024)