Junlei Wang,Xueqin Wang,Qihui Chen,Helong Xu,Man Dai,Mei Zhang,Wenyi Wang,Hua Song
The microstructure of photocatalysts plays a key role in enhancing their photocatalytic performance. Herein, resorcinol/formaldehyde (RF) polymer resin was prepared using the extended Stöber process and used for hard templates. Hollow TiO 2 spheres (HTS) were synthesized via hydrolysis of a versatile kinetics-controlled coating and carbonization method. The physicochemical properties of as-prepared catalysts were characterized. The pure RF template had a uniform diameter of ~450 nm. By adjusting the ammonia dosage from 0.1 to 0.35 mL, monodisperse RF@TiO 2 spheres were obtained with a porous TiO 2 shell of ~25–160 nm in thickness. The concentration of ammonia had a significant effect on the micromorphology, and hence, the photocatalytic properties of the HTS. The Brunauer-Emmett-Teller surface area and pore volume were ~30 m 2 /g and 0.082 cm 3 /g, respectively. The intrinsically high conductivity of the HTS microspheres and their high surface area resulting from this robust hollow structure was beneficial for photocatalytic performance toward phenol decomposition.
The relatively wide band gap (>2.0 eV) and limited light absorption ranges (only up to 600 nm) of photocatalysts severely restrict the exploitation of solar energy. Herein, we developed a Bi7.38Cr0.62O12+x crystal photocatalyst with a narrow band gap of 1.98 eV and a broad light absorption range of ∼650 nm. Unlike other broad light absorption range photocatalysts (up to ∼650 nm) such as red phosphorus, Fe2O3, and CdSe, which are either unstable or show low photocatalytic performances, the as-synthesized Bi7.38Cr0.62O12+x crystal photocatalyst exhibits a steady photocatalytic activity for the decomposition of methylene blue, methyl blue, and phenol, and production of O2.
Due to environmental pollution caused by organic pollutants, there is an urgent need to develop renewable and environmentally friendly energy sources. In this study, N-doped graphene-based CuO/WO 3 /Cu photocatalyst (CuO/WO 3 /Cu@CN) was prepared for degrading organic pollutants by using Cu(salen)PW 12 complex as the precursor and GO as the substrate. The CuO/WO 3 /Cu@CN photocatalyst not only solved the problem that CuO/WO 3 heterojunction easily expands into powder and causes poor recyclability, but also effectively promoted the separation of photoinduced e - and h + and inhibited their recombination. The catalyst can effectively catalyze the decomposition of 4-nitrophenol, and the cycle test confirmed that it has good cycle stability. Under UV–Vis light irradiation, CuO/WO 3 /Cu@CN can effectively degrade four kinds of organic dyes and the mechanism of photocatalytic degradation of organic dyes was deduced. It is worth noting that N-doped graphene regulates the band-gap of the material, leading CuO/WO 3 /Cu@CN to generate hydrogen in the photocatalytic process. This study is expected to provide a promising way for effective degradation of organic pollutants.
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