(52d) Modeling Hydrogen Evolution Reaction at the Buried Interface of Silica Coated Transition Metal Electrocatalysts from First Principles

Semipermeable oxide coatings have been shown to dramatically improve electrocatalyst stability under impure and harsh conditions without reducing catalytic performance [1], making them attractive for a wide range of applications. We have recently shown that the buried SiO₂/Pt interface of silica-coated platinum electrocatalysts is environment-dependent, and changes with the pH value of the electrolyte and the electrode potential [2]. This dynamic behavior motivated us to study how the introduction of silica coatings onto a catalytic surface can influence the kinetics and conditions for well-known reactions.

Here, we discuss the impact of silica membrane coatings on the hydrogen evolution reaction (HER) mechanism at the interface with different transition-metal(TM) surfaces. Stable configurations of the buried SiO₂/TM interface at HER conditions were determined using density-functional theory (DFT) calculations. Extending our previous work [2], we calculated interface Pourbaix diagrams for different transition-metal substrates, showing the pH and potential dependence of reaction intermediates and the hydrogen coverage on the metal surface. Activation energies for different reaction mechanisms at the buried interface were obtained from Gaussian Process Regression (GPR) accelerated Nudged Elastic Band (NEB) calculations [3].

Our modeling results indicate that the HER mechanism at buried SiO₂/transition-metal interfaces may involve direct participation of the silica membrane. Besides the protective quality of silica membranes, such an observation poses the possibility of designing synergistic membrane-coated electrocatalysts that potentially surpass the bare surfaces of earth-abundant transition metals in terms of catalytic performance (stability, activity and/or selectivity).

1. Labrador, N. Y.; Songcuan, E. L.; De Silva, C.; Chen, H.; Kurdziel, S. J.; Ramachandran, R. K.; Detavernier, C.; Esposito, D. V. ACS Catal. 2018, 8 (3), 1767–1778. https://doi.org/10.1021/acscatal.7b02668.
2. Qu, J.; Urban, A. Potential and PH Dependence of the Buried Interface of Membrane-Coated Electrocatalysts. ACS Appl. Mater. Interfaces 2020, 12 (46), 52125–52135. https://doi.org/10.1021/acsami.0c14435.
3. Garrido Torres, J. A.; Jennings, P. C.; Hansen, M. H.; Boes, J. R.; Bligaard, T. Low-Scaling Algorithm for Nudged Elastic Band Calculations Using a Surrogate Machine Learning Model. Phys. Rev. Lett. 2019, 122 (15), 156001. https://doi.org/10.1103/PhysRevLett.122.156001.