A novel SO3•- mediated photoelectrocatalytic system based on MoS2/Fe2O3 and CuNW@CF for the efficient treatment of sulfurous and nitrogenous oxides

Sulfurous and nitrogenous oxides, including NO x and SO 2 , and the generated substances NO x - and SO 3 2- widely exist in air and water as pollutants and thus are difficult to control in the environment. In this study, we designed a novel photoelectrocatalytic (PEC) system for the efficient conversion of SO 2 and NO x in mixed gases and NO x - and SO 3 2- in wastewater to N 2 and SO 4 2- , respectively, by activating SO 3 2- to form SO 3 • - . The key ideas include the conversion of SO 3 2- from SO 2 and efficient activation of SO 3 2- into SO 3 • - and further conversion into SO 4 • - by the MoS 2 /Fe 2 O 3 photoanode. Simultaneously, NO 3 - /NO 2 - originating from NO x was rapidly reduced to NH 4 + on the CuNW@CF cathode. Ultimately, the generated NH 4 + was selectively oxidized to N 2 by SO 4 • - and SO 4 • - was reduced to SO 4 2- . The results indicated that 99.9 % of TN was removed and 100 % of SO 3 2- was converted to harmless SO 4 2- . This study provides new insights into the treatment of sulfurous and nitrogenous oxides in air and water.