Constructing interfacial active sites in Ru/g-C3N4-x photocatalyst for boosting H2 evolution coupled with selective benzyl-alcohol oxidation

Engineering the interfacial active sites in metal modified semiconductor photocatalysts is highly promising but still challenging for developing heterogeneous photocatalysts with high activity and selectivity. Herein, the Ru/ g-C3N4-x photocatalyst consisting of small Ru nanoparticles (NPs) anchored on defective g-C3N4-x nanoflakes with nitrogen-vacancies (VNs) is prepared by a photoinduced method, where the photoexcited electrons of gC(3)N(4) enable the deposition of Ru NPs and the hole-generated oxidative radicals induce the formation of VN defects on g-C3N4. The Ru/g-C3N4-x photocatalyst exhibits excellent performance toward the photocatalytic redox coupling reaction of hydrogen evolution and selective oxidation of benzyl alcohol, showing the generation rates of hydrogen and benzaldehyde up to 6.42 and 5.07 mmol.g(cat)(-1).h(-1), respectively. The underlying photo catalytic mechanism is elucidated by a series of control experiments, in situ characterizations and theoretical calculations. Both experimental and theoretical studies elucidate that the synergy of interfacial Ru sites and VN defects on g-C3N4-x plays a critical role in boosting the photocatalytic redox coupling reaction. The Ru/g-C3N4-x heterointerface not only accelerates the separation of photogenerated charge carriers but also provides the optimum active sites for H-2 evolution and benzyl-alcohol oxidation.

Automated summary

Engineering interfacial active sites in metal modified semiconductor photocatalysts is a challenging task. In this study, Ru/g-C3N4-x photocatalyst with small Ru nanoparticles anchored on defective g-C3N4-x nanoflakes is prepared. The photocatalyst exhibits excellent performance in hydrogen evolution and selective oxidation of benzyl alcohol, attributed to the synergy of interfacial Ru sites and VN defects on g-C3N4-x.