Photocatalytically splitting water into hydrogen upon semiconductors has tremendous potential for alleviating environmental and energy crisis issues. There is increasing attention on improving solar light utilization and engineering photogenerated charge transfer of TiO2 photocatalyst because it has advantages of low cost, non-toxicity, and high chemical stability. Herein, oxygen vacancies and cocatalysts (Cu and MoS2) were simultaneously introduced into TiO2 nanoparticles from protonic titanate by a one-pot solvothermal method. The composition and structure characterization confirmed that the pristine TiO2 nanoparticle was rich in oxygen vacancies. The photocatalytic performances of the composites were evaluated by solar-tohydrogen evolution test. The results revealed that both Cu-TiO2 and MoS2- TiO2 could improve the photocatalytic hydrogen evolution ability. Among them, 0.8% Cu-TiO2 showed the best hydrogen evolution rate of 7245.01 μmol·g−1·h−1, which was 3.57 and 1.34 times of 1.25% MoS2- TiO2 (2726.22 μmol·g−1·h−1) and pristine TiO2 material (2028.46 μmol·g−1·h−1), respectively. These two kinds of composites also had good stability for hydrogen evolution. Combined with the results of photocurrent density and electrochemical impedance spectra, the incorporation of oxygen vacancies and cocatalysts (Cu and MoS2) could not only enhance the light-harvesting of TiO2 but also improve the separation and transfer capabilities of light-induced charge carriers, thus promoting water splitting to hydrogen.

Photocatalytic CO2 reduction is a promising approach for reducing CO2 emissions and achieving the goal of carbon neutrality. In this work, selectively coupling Cu(OH)2 and CuO with amine-modified brookite TiO2 ( NH2–B–TiO2) has been achieved by a simple precipitation method. The results show that CuO is better than Cu(OH)2 as a co-catalyst to enhance the CO2 photoreduction capability of NH2– B–TiO2. The highest rates of CO2 conversion to CH4 and CO of NH2– B–TiO2–CuO composite reach 6.05 and 3.25 μmol h− 1 g− 1, respectively, which is higher than 8 times the yield of CH4 of NH2– B–TiO2. It is proposed that the NH2– B–TiO2–CuO composite offers an effective charge transfer through the formation of a p–n junction between NH2– B–TiO2 and CuO interfaces, while in the NH2– B–TiO2–Cu(OH)2 composite, the Cu(OH)2 dominantly serves as an electron sink to capture photo-induced electrons, promoting photo-induced carrier separation. This work provides an ingenious synthetic method for selectively anchoring Cu(OH)2 and CuO on semiconductors with different charge transfer routes for an efficient CO2 photoreduction.