Lumeng Jia, Wenchao Yu, Xiangting Hou, Mengxue Li, Qi Shi, Zhaoyong Bian, Hui Wang
Photoelectrocatalytic (PEC) in situ hydrogen peroxide (H2O2) production offers a green strategy for activating singlet oxygen (1O2) and degrading refractory organic pollutants. However, it suffers from low cathode yield, sluggish anode kinetics, mass-transfer losses, and low selectivity for 1O2. This study ingeniously designed an S-O double vacancy β-In2S3-Er/Yb@WO3-Ov S-type heterojunction full-spectrum photoanode, offered new perspectives on in situ oxygen reduction at the photoanode for H2O2 generation, and presented a dual-electrode cooperative PEC system. In the experiment, double vacancies at the photoanode acted as electron traps, accumulating electrons. Meanwhile, an applied bias voltage, more electrons on the surface, and weakly acidic and oxygen-permeable conditions the electrons trapped by vacancies, together with conduction band electrons, were conducive to driving the in-situ two-electron oxygen reduction reaction to H2O2 formation at the photoanode. O vacancies dominated interfacial adsorption and catalysis, while S vacancies served as electron traps for charge separation, forming a complementary synergy. Coupled with charge modulation at the S-scheme heterojunction interface, accelerating photogenerated carrier separation and preserved highly reactive holes, providing key conditions for 1O2 generation. β-In2S3-Er/Yb@WO3-Ov photoanode realized in-situ oxygen reduction reaction-induced H2O2 production and cathodic H2O2 activation simultaneously. Both routes yield ·OOH/·O2- intermediates, which were oxidized by holes to form 1O2, thereby enabling efficient carbamazepine removal (98.4%, kapp = 0.093 min-1), efficient 1O2 production (53.13 μmol/(L·min)), and low energy consumption (0.155 kWh/m3-log). This work presents an advanced PEC strategy for the synergistic synthesis of H2O2 and 1O2, offering a promising approach for high-efficiency environmental remediation.