Deep insight into ROS mediated direct and hydroxylated dichlorination process for efficient photocatalytic sodium pentachlorophenate mineralization

• Bi cocatalyst in tandem with oxygen vacancies well regulated the ROS generation. • BMO-Bi-OVs well achieved the boosting of 1 O 2 and O 2 − without OH formation. • The underlying role of ROS in the dechlorination of NaPCP was unveiled. • NaPCP was mineralized and detoxified efficiently. Herein, we designed and constructed a model photocatalyst oxygen-deficient Bi@Bi 2 MoO 6 (Bi-BMO-OVs) through a one-step solvothermal synthesis to deliberately regulate ROS generation and seek the crucial function of ROS during sodium pentachlorophenate (NaPCP) photochemical decomposition. The metallic Bi and oxygen vacancies (OVs) introduced in Bi 2 MoO 6 prominently encouraged the yields of 1 O 2 and O 2 − , and synchronously blocked the formation of powerful OH. Unlike the nonselective performance of OH, 1 O 2 and O 2 − were experimentally and theoretically substantiated to account for the direct dichlorination and hydroxylated dichlorination respectively during photocatalytic NaPCP decomposition. With more O 2 − and 1 O 2 involved in the dechlorination process of NaPCP, easily decomposable quinone intermediates were produced, thereby realizing the rapid and efficient mineralization of NaPCP. This present work casts a new light on ROS mediated visible light photocatalytic decomposition of polychlorinated organic pollutants and opens up new possibilities for achieving their rapid detoxication via precise ROS regulation.