BiOBr/COF S-scheme photocatalyst for H_(2)O_(2) production via concerted two-electron pathway

Constructing step-scheme(S-scheme)heterojunctions has become a popular strategy for efficient pho-tocatalytic H_(2)O_(2) generation.Herein,we in situ grew BiOBr nanosheets(NSs)on a Schiff-base covalent organic framework(COF)with largeπ-conjugated structures to prepare S-scheme BiOBr/COF photocat-alysts for H_(2)O_(2) synthesis.The highest photocatalytic H_(2)O_(2) production performance of the composite sample constituting the S-scheme heterojunction is 3749μmol g−1 h−1,which was 1.85 and 27 times the rates of COF and BiOBr,respectively.The construction of S-scheme heterojunction contributed to ef-ficient carrier transfer and separation in space and enhanced redox power.Moreover,the lying-down O_(2)-adsorption configuration on the COF surface favors the concerted two-electron O_(2) reduction process,which greatly reduced the reduction potential requirement for O_(2)-to-H_(2)O_(2) conversion.The synergy be-tween the S-scheme heterojunction and the unique O_(2)-COF interaction boosted photocatalytic H_(2)O_(2) pro-duction activity.