Facet‐Dependent Intrinsic Activity of Single Co3O4 Nanoparticles for Oxygen Evolution Reaction

• Published in: Advanced functional materials Vol. 33; no. 1
• Main Authors: Liu, Zhibin, Amin, Hatem M. A., Peng, Yuman, Corva, Manuel, Pentcheva, Rossitza, Tschulik, Kristina
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc 03.01.2023
• Subjects: Catalytic activity; Cobalt oxides; Cubes; Density functional theory; density functional theory calculations; Materials science; Metal oxides; Nanoparticles; Oxidation; Oxygen evolution reactions; single entity electrochemistry; Spheroids; surface facets; Water splitting
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.202210945

Deciphering the influence of nanocatalyst morphology on their catalytic activity in the oxygen evolution reaction (OER), the limiting reaction in water splitting process, is essential to develop highly active precious metal‐free catalysts, yet poorly understood. The intrinsic OER activity of Co3O4 nanocubes and spheroids is probed at the single particle level to unravel the correlation between exposed facets, (001) vs. (111), and activity. Single cubes with predominant (001) facets show higher activity than multi‐faceted spheroids. Density functional theory calculations of different terminations and reaction sites at (001) and (111) surfaces confirm the higher activity of the former, expressed in lower overpotentials. This is rationalized by a change in the active site from octahedral to tetrahedral Co and the potential‐determining step from *OH to *O for the cases with lowest overpotentials at the (001) and (111) surfaces, respectively. This approach enables the identification of highly active facets to guide shape‐selective syntheses of improved metal oxide nanocatalysts for water oxidation. Nano‐impact measurement of spherical and cubic Co3O4 single nanoparticles is a key‐enabling tool to quantify the intrinsic effect of facets on the activity of nanocatalysts toward the oxygen evolution reaction. The data reveal that single Co3O4 cubes are more active than spheres. This result is confirmed by state‐of‐the‐art density functional theory calculations, deepening our understanding of the facet structure‐activity relationships.