The photocatalytic conversion of CO2 and H2O into useful chemicals or fuels over semiconductor photocatalysts is regarded as a promise technology to settle the problems of global warming and energy exhaustion. Whereas, the inefficient photo-absorption and slow charge dynamics limit the CO2 photoreduction efficiency. Here, a ternary heterojunction photocatalyst Cu2Cl(OH)3/In/In2O3 (Cu H IO) with intimate interface is obtained via hydrogen chemical reduction approach followed by hydrolysis reaction, where In species can be produced on the surface of In2O3 from the hydrogen chemical reaction with the calcining temperature over 500℃. The Cu H IO exhibits enhanced photocatalytic activity of CO2 conversion to the pristine In2O3, In2O3 with In species (H IO), and Cu2Cl(OH)3/In2O3 (Cu IO). On the absence of sacrificial agent or cocatalyst, the yield rate of CO and CH¬4 over Cu H IO are 4.36 and 1.09 μmol·g-1·h-1, which is 8.38-fold and 18-fold that of pristine In2O3 (0.52 and 0.06 μmol·g-1·h-1), respectively. The photocatalytic performance enhancement of Cu H IO results from the construction of the ternary heterojunction, which synchronous improve the photo-response and charge separation of In2O3. Moreover, the possible CO2 reduction pathway over Cu H IO has also been investigated and proposed. This work provides an important strategy for developing high-efficiency heterojunction photocatalyst system for solar fuel generation.
Amorphous-TiO2/Cu2Cl(OH)3 (am-TiO2/Cu2Cl(OH)3) composite photocatalyst was synthesized by a facile and novel spray pyrolysis method. The morphology, crystal structure, chemical composition, optical properties, and photocatalytic activity of the composite were characterized and investigated. It was noted that heating temperature played a fundamental role in determining the morphology of the composite photocatalyst as well as the crystallinity of TiO2. Am-TiO2 was firmly anchored on Cu2Cl(OH)3 with well dispersibility and served as the main sunlight absorber. Meanwhile, Cu2Cl(OH)3 acted as not only a carrier, but also a chemical catalyst of H2O2 to produce O2 (electron acceptor). Compared with commercially available P25 specie, the composite with the addition of H2O2 exhibited higher photocatalytic performances for methyl orange (MO) degradation under simulated solar light irradiation. By considering the mechanism, the excellent performance was awarded to uniform dispersion of am-TiO2 in the unique Cu2Cl(OH)3 and superfluous electron acceptor.