Defects Induced in Situ Reconstruction of CdS with Oxygen-Tolerance Up to 23% in the Photocatalytic CO₂ Reduction

Direct driving the photocatalytic reduction of CO₂ from air or flue gas to produce value-added chemicals and fuels is very challenging due to the suppressing effect of the more favorable thermodynamically oxygen reduction reaction (ORR). Herein, we presented a novel oxygen-involved reconstruction pathway on a unique defective CdS-D in the photocatalytic reduction of CO₂. The material is highly tolerant to O₂ and generates 2766.7 µmol g^-1 h^-1 of CO under visible light irradiation in the presence of up to 23% content of O₂. Intriguingly, instead of inhibiting the performance of CO₂ reduction, the presence of oxygen positively promotes it, CO generation rate is up to 5124 µmol g^-1 h^-1 after multiple experimental cycles. The meticulously structural analysis reveals that the CdS-D with abundant defects tended to accumulate photogenerated holes, and S^2- is oxidized to SO₄ ^2- in the presence of oxygen to produce Cd₂SO₄(OH)₂ as the active center for preferable CO₂ adsorption and inhibit the O₂ adsorption, which is the root cause for the high tolerance of oxygen in CO₂ reduction (CO₂RR). This work reveals a unique reconstruction process of sulfides photo corrosion, which provides a new idea for realizing the direct conversion of low-concentration CO₂ by omitting expensive carbon capture or purification in industrial carbon resource utilization.