The Sensitivity of Metal Oxide Electrocatalysis to Bulk Hydrogen Intercalation: Hydrogen Evolution on Tungsten Oxide

Abstract

Metal oxides are attracting increased attention as electrocatalysts owing to their affordability, tunability, and reactivity. However, these materials can undergo significant chemical changes under reaction conditions, presenting challenges for characterization and optimization. Herein, we combine experimental and computational methods to demonstrate that bulk hydrogen intercalation governs the activity of tungsten trioxide (WO 3 ) toward the hydrogen evolution reaction (HER). In contrast to the focus on surface processes in heterogeneous catalysis, we demonstrate that bulk oxide modification is responsible for experimental HER activity. Density functional theory (DFT) calculations reveal that intercalation enables the HER by altering the acid−base character of surface sites and preventing site blocking by hydration. Firstprinciples microkinetic modeling supports that the experimental HER rates can only be explained by intercalated H x WO 3 , whereas nonintercalated WO 3 does not catalyze the HER. Overall, this work underscores the critical influence of hydrogen intercalation on aqueous cathodic electrocatalysis at metal oxides.

Impact of Reversible Proton Insertion on the Electrochemistry of Electrode Materials Operating in Mild Aqueous Electrolytes: A Case Study with TiO2

“…[ 27 ] More recently, the Augustyn and Mpourmpakis/McKone groups have both suggested that protons inserted into WO 3 govern the reactivity toward the hydrogen evolution reaction. [ 28,29 ] All these elements reinforce the idea that there is a crucial need to elucidate the key factors governing PICET reactions, and more specifically in aqueous unbuffered media. This is of prime interest for the development/optimization of not only water‐based electrochemical charge storage devices, but also of many water‐based energy conversion systems.…”

Gaseous CO2 Coupling with N-Containing Intermediates for Key C–N Bond Formation during Urea Production from Coelectrolysis over Cu

“…The linear Poisson–Boltzmann implicit solvation model as implemented in VASPsol with a Debye screening length of 3.0 Å was utilized to simulate water (dielectric constant = 78.4) and the electrolyte and maintain the neutrality of the simulation cell . The details regarding how to correct the electronic energy due to an electron being added to or removed from the system and how to construct free energy surfaces can be found in the Supporting Information (SI) or our previous works. , This approach has been used by our group ,− and others − to study a variety of electrochemical reactions. Some recent theoretical studies have suggested that better thermodynamics of overall electrochemical reactions can be achieved by correcting the computed free energies of the gas molecules involved in the reactions. − We found that applying the correction suggested by Calle-Vallejo and co-workers to CO 2 , which is the only molecule in the current system, leads to no change in our major conclusions (Table S2).…”

Interface catalytic regulation via electron rearrangement and hydroxyl radicals triggered by oxygen vacancies and heavy metal ions

“…Nano-metal oxide catalysts offering intriguing properties and stability, and low price are the subject of intense investigation, particularly in the energy and environment-related catalysis eld. [1][2][3][4] However, some nano-metal oxides, like TiO 2 , CeO 2 , and ZrO 2 , suffer from poor catalytic efficiency due to their low electron transfer rates and limited active sites, greatly restricting their application. [5][6][7][8] To this end, manufacturing oxygen vacancies (OVs) on them is a simple and convenient way to enhance their intrinsic catalytic properties, which aroused tremendous interest.…”