Multifaceted Cu2O with controlled crystal facet exposure was synthesized via a facile one-step method. It was found that photogenerated electrons prefer to accumulate on high index planes, while holes tend to migrate to {100} facets of a Cu2O polyhedron, leading to efficient charge separation and enhanced photocatalytic reforming of glucose.

Traditionally, Cu ion-based oxide materials are considered not functional as photocatalysts owing to their instability in the photoelectrochemical processes. Here, we report on the light-induced photochemical synthesis of Cu 2 O microcubes utilizing CuWO 4 as the precursor. It was found that under light irradiation and in the presence of glucose CuWO 4 could be reduced in situ into Cu 2 O with its morphology reassembled from irregular bulk particles to hollow microcubes. Similar morphology transformation could not be observed when CuO or Cu(NO 3 ) 2 were used as precursors. More importantly, the in situ photochemical-synthesized Cu 2 O naoncubes showed both high activity and excellent stability for glucose reforming under visible light, which overcame the general barrier of Cu 2 O instability in photochemical processes. The activity could be remarkably enhanced when 0.1 wt % Zn was doped into the Cu 2 O. The excellent performances of the material were related to the existence of hollow microcubes and the modified band structure due to Zn doping.

Nanosized photocatalysts have been shown to be important to many modern photocatalytic reactions. Control of the microstructure of the nanocrystals enables regulation of their optical properties and enhancement of specific reactions. Here, Cu(2+)-doped ZnS nanosphere photocatalysts with hierarchical nanostructures and controllable sizes were synthesized via a facile wet-chemical reaction. We demonstrated that small amounts of Cu(2+) doping could give rise to the formation of a variety of localized, nanosized Cu(1-x)Zn(x)S solid solutions that are separated by a continuous ZnS medium. The nano-solid-solutions have predictable band structures and an average size of several nanometers, which ensure facile generation of electron-hole pairs by visible light irradiation and quick migration of the photo-generated charges to the interfaces. With Ru as a cocatalyst, the as-prepared 0.5 mol% Cu(2+)-doped ZnS nanospheres showed a high H2 evolution rate of 1.03 mmol h(-1), corresponding to a quantum efficiency of 26.2% at 425 nm. A hierarchical surface structure with a large surface area is considered crucial for the increased activity. Our work not only showed that the non-toxic metal chalcogenides achieve high efficiency but also provides a new concept of localized nano-solid-solution for photocatalytic applications.

Abstract