Construction of ternary heterojunction photocatalyst Cu2Cl(OH)3/In/In2O3 for boosted photocatalytic CO2 reduction performance

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.