Efficient photocatalytic chlorine production on bismuth oxychloride in chloride solution

Chlorine (Cl2) one of the most important base chemicals, is manufactured conventionally by electrolysis of saturated NaCl solution in chlor-alkali process which suffers from high power consumption and economic constraints. Herein, we report the novel light-driven chlorine evolution reaction (CER) in synthetic seawater using bismuth oxychloride (BiOCl) photocatalyst, providing an economical and convenient route for Cl2 production. A superior Cl2 production rate of 19.6 μmol h−1 (about 27.79 mg L−1 h−1) is achieved, which is sufficient for methane functionalization and production of chlorine-based disinfectant. Experimental and theoretical studies reveal that the Cl− extraction from and insertion into the open structure of BiOCl contribute to the excellent performance. The lattice Cl− could be self-oxidized to form Cl2, while Cl− in solution would fill the lattice Cl− vacancies, making CER continue. This technique is also applicable to Br2 production. This work opens up prospects for halogen production based on solar energy.