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Hydrogen peroxide (H2O2) is an essential and versatile oxidant. The photocatalytic production of H2O2 is a promising alternative to the conventional anthraquinone oxidation process. In this work, BiOBr nanosheets with oxygen vacancies (OVs) were successfully synthesized by a solvothermal method in the presence of mannitol. The character of the nanosheets shortened the diffuse length of charge carriers, which is beneficial for the charge separation. The introduction of OVs enhanced the visible light absorption and also improved the carrier separation. Furthermore, OVs enhanced the activation of O2 molecules and facilitated the generation of ˙O2−. As a result, the products exhibited good performance in photocatalytic H2O2 production. After introducing HCOOH, the yield of H2O2 was further enhanced by a factor of 50, from 3 μmol h−1 to 150 μmol h−1. This work provides a reference to design high performance photocatalysts for H2O2 production through defect engineering. [ABSTRACT FROM AUTHOR]

As one of the most commonly bulky chemicals, chlorine is conventionally manufactured by electrolysis of NaCl solution in the chlor–alkali process, which requires a huge supply of electrical energy. The photocatalytic route to produce chlorine by using solar energy and NaCl solution offers a promising strategy to reduce energy consumption and bring economic benefits. Herein, it was found that the introduction of CO2 would enhance the productivity of Cl2 from 8.24 μmol⋅h−1 to 39.6 μmol⋅h−1 in NaCl solution over BiOCl. Experimental studies reveal that the CO2 species (CO32−) entered into the crystal texture of BiOCl and the interlayer space between [Bi2O2]2+ slabs were increased and distorted, accelerating the cycle of Cl species. Besides, the cycle of carbonate species also existed and accelerated the reaction efficiency of Cl− oxidation to Cl2. This work provides a new feasible method of using abundant CO2 resources to accelerate the process of chlorine production via photocatalysis. [ABSTRACT FROM AUTHOR]