Ambient-Stable Black Phosphorus-Based 2D/2D S-Scheme Heterojunction for Efficient Photocatalytic CO2 Reduction to Syngas

Black phosphorus (BP), an emerging remarkable photocatalytic semiconductor, is arousing strong interests in this field of solar-driven CO2 reduction, but its stability and activity are still facing huge challenges. Here, an ambient-stable and effective 2D/2D heterostructure of BP/bismuth tungstate (Bi2WO6) with oxygen vacancy is innovatively designed for syngas production via photocatalytic CO2 reduction. This work, not only resolves the stability problem of BP nanosheets by anchoring ultrasmall platinum (Pt) nanoparticles (∼2 nm) but also greatly improves the charge transfer efficiency by constructing S-scheme 2D/2D heterostructure with coupled oxygen defects. As a result, the generation rates of carbon monoxide (CO) and hydrogen (H2) remarkably reach 20.5 and 16.8 μmol g–1 h–1, respectively, which are much higher than that of reported BP-based materials, and the accomplished CO/H2 ratios (1:1–2:1) are exactly the most desirable syngas for industrial applications. Thus, this work constructs an efficient and ambient-stable BP-based photocatalyst for syngas production by CO2 reduction at mild conditions.