Pd modified defective HNb3O8 with dual active sites for photocatalytic coproduction of hydrogen fuel and value-added chemicals

Abstract Developing photocatalysts for coproduction of hydrogen fuel and valuable chemicals is highly desired but still challenging. Herein, Pd-modified defective HNb3O8 photocatalyst (denote as Pd/HNb3O8-H2) consisting of dispersive Pd sites and abundant surface oxygen vacancies (VOs) was prepared via the thermal treatment of Pd2+-incorporated HNb3O8 in H2/Ar gas. The existence of Pd favors the formation of VOs on HNb3O8, enabling the synchronous construction of Pd and VO dual active sites. The spectroscopy and photoelectrochemical studies demonstrate the advantages of Pd/HNb3O8-H2 photocatalyst in promoting the separation and migration of photoinduced charge carries. The Pd/HNb3O8-H2 photocatalyst exhibits the outstanding performance toward photocatalytic proton reduction coupled with selective benzyl-alcohol oxidation, achieving the optimal production rates of H2 and benzaldehyde as high as 3.17 and 2.76 mmol·gcat−1 h−1, respectively. The experimental and theoretical investigations have expounded the synergistic mechanism of Pd and VO dual active sites in boosting photocatalytic coproduction of H2 and benzaldehyde.