Novel p- and n-type S-scheme heterojunction photocatalyst for boosted CO2 photoreduction activity

S-scheme photocatalysts are more efficient than the conventional type-II configuration, but the CO 2 reduction performances are still unsatisfactory. Herein, we firstly report the layered double hydroxide (LDH) based S-scheme heterostructure photocatalyst (NiIn LDH/In 2 S 3 ) with n-type NiIn LDH and p-type In 2 S 3 . The built-in internal electric field directs the photogenerated electrons flow from the conductive band of In 2 S 3 to the valance band of NiIn LDH, which is confirmed by operando and theoretical experiments. The CO 2 photoreduction intermediates are monitored by in-situ Raman spectra, and the density functional calculations disclose the reduced energy barrier for CO desorption on the heterojunction. Therefore, without cocatalysts or sacrificial agents, the NiIn LDH/In 2 S 3 heterojunction delivers a high CO yield rate of 29.43 μmol g −1 h −1 under visible light irradiation, ca. 3.5 and 4.3 times higher than the single counterpart NiIn LDH and In 2 S 3 . Notably, this value is the highest among S-scheme CO 2 photocatalysts and surpasses most top-ranking benchmarks.