Crystal facet modulation of Bi₂WO₆ microplates for spatial charge separation and inhibiting reverse reaction

We experimentally demonstrated that spatial charge separation can take place between the {010} and {001} facets of Bi₂WO₆ microplates. Further assembly of the reduction and oxidation cocatalysts leads to a remarkable enhancement of photocatalytic water oxidation activity in the presence of Fe³⁺ ions while the reverse oxidation of Fe²⁺ to Fe³⁺ ions is totally inhibited. The origin of the driving force is theoretically proven to be the difference in surface work function between the co-exposed facets, which shows a feasible strategy for developing efficient photocatalysts for solar energy conversion.