Polyhedral 30‐Faceted BiVO₄ Microcrystals Predominantly Enclosed by High‐Index Planes Promoting Photocatalytic Water‐Splitting Activity

Unprecedented 30‐faceted BiVO 4 polyhedra predominantly surrounded by {132}, {321}, and {121} high‐index facets are fabricated through the engineering of high‐index surfaces by a trace amount of Au nanoparticles. The growth of high‐index facets results in a 3–5 fold enhancement of O 2 evolution from photocatalytic water splitting by the BiVO 4 polyhedron, relative to its low‐index counterparts. Theory calculations reveal that water dissociation is more energetically favorable on the high‐index surfaces than on the low‐index (010), (110), and (101) surfaces, which is accompanied by a notable reduction in the overpotential (0.77–1.14 V) for the oxygen evolution reaction. The apparent quantum efficiency of O 2 generation without an external electron supply reaches 18.3% under 430 nm light irradiation, which is an order of magnitude higher than that of the catalysts reported hitherto.