Strong metal-support interaction on BiOBr{010} plane improved selectivity in photocatalytic H2O2 synthesis

Despite its potential as a visible-light-responsive photocatalyst, the practical application of BiOBr is hindered by rapid charge recombination and an insufficient number of surface-active sites. While crystal plane engineering can guide the directional migration of photogenerated carriers to specific facets, enhancing separation, this approach alone yields limited performance gains. To further boost photocatalytic H 2 O 2 production, this study employed a combined strategy of crystal plane regulation and Au nanoparticle loading. Notably, this simple metal modification not only facilitates charge separation but also induces a clear swap of the dominant reaction pathways on specific BiOBr facets. Specifically, Au loading transforms the primary role of the {010} plane from water oxidation to oxygen reduction for H 2 O 2 generation, while on the {001} plane, it shifts from oxygen reduction to water oxidation. Such a reciprocal switching of facet-specific functions via metal decoration has rarely been explored in BiOBr or similar layered photocatalysts. Remarkably, the Au-loaded BiOBr{010} achieved a H 2 O 2 production rate of 2273 μmol·h −1 ·g −1 , which is 15.5 times higher than that of the pristine counterpart. This dramatic enhancement is primarily due to the formation of Au δ+ species, which act as new active sites and significantly improve oxygen adsorption on the catalyst surface.