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.

复合半导体的构造是通过延长光生空穴和电子的寿命来提高光催化效率的有效解决方案。在此，通过简便的原位水热条件合成了异质结结构的复合BiVO ₄ / Bi ₄ Ti ₃ O ₁₂。新型复合光催化剂具有出色的光催化能力，可将H ₂ O还原CO ₂转化为CH ₃ OH和CO。BiVO ₄ /10％Bi ₄ Ti ₃ O ₁₂样品显示最高CH ₃ OH和CO产率，最高可达16.6和1。 13.29μmolg ^-1 h ^-1，分别比纯BiVO _4的高12.39倍和5.68倍，比纯Bi ₄ Ti ₃ O _12的高9.88倍和2.80倍。如此高的活性归因于II型异质结结构，该结构显着增强了光生载流子的分离，并促进了Bi ₄ Ti ₃ O ₁₂上的水氧化与BiVO ₄上的CO ₂还原之间的协同作用。根据实验结果，提出了CO ₂在复合材料上的光催化反应机理。