CO2-mediated photocatalytic chlorine production over bismuth oxychloride in chloride solution.

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 using solar energy and NaCl solution offers a promising strategy to reduce energy consumption and bring economic benefits. Herein, we 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.