BiVO4 /Bi4Ti3O12 heterojunction enabling efficient photocatalytic reduction of CO2 with H2O to CH3OH and CO

Construction of composite semiconductors is an effective solution to elevate the efficiency of photocatalysis by prolonging lifetime of photogenerated hole and electrons. Herein, a heterojunction structure composite BiVO4/Bi4Ti3O12 was synthesized via a facile in situ hydrothermal condition. The novel composite photocatalyst has excellent photocatalytic ability to reduce CO2 with H2O into CH3OH and CO. The BiVO4/10 % Bi4Ti3O12 sample shows the highest yields of CH3OH and CO up to 16.6 and 13.29 μmol g−1 h−1, which was 12.39 and 5.68 times higher than that of pure BiVO4, and 9.88 and 2.80 times higher than that of pure Bi4Ti3O12, respectively. Such a high activity is attributed to the type II heterojunction structure which significantly enhances separation of photogenerated carriers and promotes collaboration between the water oxidation on the Bi4Ti3O12 and the CO2 reduction on BiVO4. The photocatalytic reaction mechanism of CO2 on the composite was proposed according to experiment results.