Oxygen Vacancy Induced Atom-Level Interface in Z-Scheme SnO/SnNbO Heterojunctions for Robust Solar-Driven CO Conversion.

The modulation of Z-scheme charge transfer is essential for efficient heterostructure toward photocatalytic CO reduction. However, constructing a compact hetero-interface favoring the Z-scheme charge transfer remains a great challenge. In this work, an interfacial Nb-O-Sn bond and built-in electric field-modulated Z-scheme O-SnO/SnNbO heterojunction was prepared for efficient photocatalytic CO conversion. Systematic investigations reveal that an atomic-level interface is constructed in the O-SnO/SnNbO heterojunction. Under simulated sunlight irradiation, the obtained O-SnO/SnNbO photocatalyst exhibits a high CO evolution rate of 147.4 μmol h g from CO reduction, which is around 3-fold and 3.3-fold of SnO/SnNbO composite and pristine SnNbO, respectively, and favorable cyclability by retaining 95.8% rate retention after five consecutive tests. As determined by electron paramagnetic resonance spectra, in situ Fourier transform infrared spectra, and density functional theory calculations, Nb-O-Sn bonds and built-in electric field induced by the addition of oxygen vacancies jointly accelerate the Z-scheme charge transfer for enhanced photocatalytic performance. This work provides a promising route for consciously modulating Z-scheme charge transfer by atomic-level interface engineering to boost photocatalytic performance.