Piezotronic effect and hierarchical Z-scheme heterostructure stimulated photocatalytic H2 evolution integrated with C-N coupling of benzylamine

Abstract

Photocatalytic hydrogen generation represents a potential approach to address global energy and environmental issues for artificial photosynthesis. Generally, the inevitable use of the holes scavengers leads to increased cost and production of waste. The integration of H2-producing half-reaction with value-added organic molecule oxidation reaction provides a promising strategy to cope with this issue. However, owing to the low separation efficiency of photo-generated charge carriers and sluggish kinetics of the surface reaction, the photocatalytic activity without a co-catalyst is unsatisfying. Herein, the hierarchical and piezoelectric Z-scheme BaTiO3@ZnIn2S4 heterostructure without any co-catalyst were dexterously constructed. The Z-scheme electron transfer paths maintain the strong redox ability of the photo-generated electrons and holes, also offer spatial separation of both charge carriers and the surface redox regions. The well-designed redox regions endow BaTiO3@ZnIn2S4 with the lowest energy barriers of hydrogen production and C-N coupling of benzylamine than that of pure BaTiO3 or ZnIn2S4. Significantly, piezotronic effect can further accelerate the separation and transfer of photo-generated charge carriers in Z-scheme BaTiO3@ZnIn2S4 heterostructure. Thus, by the feat of the multiple advantages of the piezotronic effect and Z-scheme heterostructure, the high photocatalytic activity for the co-production of C-N coupling products (5593 umol g−1) and H2 (8041 umol g−1) was achieved through coupling utilization of mechanical energy and solar energy.