Photoredox dual reaction for selective alcohol oxidation and hydrogen evolution over nickel surface-modified ZnIn2S4

A binary nickel surface-modified ZnIn2S4 (Ni:ZIS) composite has been synthesized via photochemical reduction approach. The synergy of improved photogenerated charge transfer behavior and Ni-assisted α-H abstraction leads to the boosted photocatalytic performance of Ni:ZIS for product-oriented alcohol oxidation integrated with hydrogen evolution. [Display omitted] •Nickel surface modified ZnIn2S4 (Ni:ZIS) composites are synthesized.•The Ni:ZIS composites exhibit enhanced photoactivity for photoredox reaction.•Ni-assisted α-H abstraction tunes the selectivity of benzyl alcohol (BA) conversion.•A tentative photocatalytic BA conversion mechanism over the Ni:ZIS composites is proposed. The photocatalytic coupling reaction can be conducted in one pot to realize the simultaneous utilization of electrons and holes, thereby obtaining value-added fine chemicals and fuels. Herein, we report a binary nickel modified ZnIn2S4 (Ni:ZIS) for highly efficient photocatalytic selective oxidation of benzyl alcohol (BA) to benzaldehyde (BAD) integrated with hydrogen (H2) evolution, in which Ni can promote photogenerated charge transfer for enhancing photoactivity. Particularly, the products of converting BA to aromatic compounds over blank ZnIn2S4 (ZIS) and Ni:ZIS show a marked difference under the same reaction conditions. Hydrobenzoin (HB) is the primary product over blank ZIS. After the introduction of Ni, the formation of HB is dramatically suppressed, resulting in higher selectivity of BAD, because the introduction of Ni facilitates the α-H abstraction. In addition, an analogous phenomenon has been observed on Ni-based compounds modified ZIS, such as NixP and NiS. It is hoped that this work would provide a feasible paradigm for modifying the surface of photocatalysts to tune the selectivity of product-oriented alcohols oxidation coupled with H2 evolution in water.