Bi 3 O 4 Cl/g-C 3 N 4 /Cd 0.5 Zn 0.5 S Double Z-Scheme Heterojunction Photocatalyst for Highly Selective CO 2 Reduction to Methane.

Solar-energy-driven CO 2 hydrogenation is a promising strategy to alleviate the climate crisis. Methane is a desirable derivative of CO 2 reduction. However, developing a photocatalyst for highly active and selective CH 4 generation remains challenging. Herein, we report a double Z-scheme Bi 3 O 4 Cl/g-C 3 N 4 /Cd 0.5 Zn 0.5 S photocatalyst for efficient reduction of CO 2 to CH 4 . In situ characterization techniques confirmed that the charge migration mechanism in Bi 3 O 4 Cl/g-C 3 N 4 /Cd 0.5 Zn 0.5 S promotes charge separation through double internal electric fields. As a result, the optimized C0.01B0.02C catalyst displayed a formation rate high up to 25.34 μmol g -1 h -1 and a selectivity of 96.52% of CH 4 . Moreover, the AQY of CO 2 conversion on C0.01B0.02C (1.84%) was almost 41 times higher than that of the bare CN. This study provides a novel perspective to develop heterojunction photocatalysts for selective CO 2 conversion to CH 4 .