Bifunctional Lewis acid-base nanocatalysts with dual active sites for strengthened coupling of alcohol conversion and H2 evolution

Abstract

The synergistic of organic transformation with H2 production in one redox cycle is highly desirable to achieve the full use of photogenerated holes and electrons but challenging. Herein, Lewis acid-base nanocatalysts in which Ni decorated defective ZnIn2S4 (denoted as Ni/VZIS) has been prepared through photodeposition with Zn defective ZnIn2S4 nanosheets as precursor. The Zn vacancies favors the selective deposition of Ni, enabling the co-exposure of Lewis acid Ni and Lewis base S adjacent dual active sites. In-situ FTIR results reveal the coexistence of Ni and Zn vacancy on ZnIn2S4 favored the chemisorption of benzyl alcohol. The electron-deficient Ni Lewis acid (LA) site and electron-rich S Lewis base (LB) site can act as benzyl alcohol conversion and H2 evolution sites, respectively, thus facilitating the full use of photoinduced electrons and holes. The spectroscopy and photoelectrochemical studies demonstrate the transfer and separation of photogenerated carries are also facilitated in the nanohybrids. As such, the Ni/VZIS photocatalyst show outstanding performance of photocatalytic conversion benzyl alcohol (BA) into benzaldehyde (BAD) and H2, with the optimal H2 generation rate of 81.9 μmol h−1, accompanying benzaldehyde generation rate of 73.7 μmol h−1. This work provides a profound insight into the designing of multi-functionalized nanohybrids for the full use of photoexcited electrons-holes pairs.