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

Abstract

Unprecedented 30-faceted BiVO₄ 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 O₂ evolution from photocatalytic water splitting by the BiVO₄ 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 O₂ 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.

A 30-faceted BiVO₄ polyhedron predominantly surrounded by {132}, {321}, and {121} high-index facets is synthesized. This BiVO₄ polyhedron exhibits an enhanced O₂ generation rate over that of low-index counterparts, which originates from energetically favorable water dissociation and a notable reduction in the overpotential of the oxygen evolution reaction on the high-index surfaces relative to that on the low-index surfaces.

http://ift.tt/2zqOTqn