Plasmonic Ag-nanoparticles decorated phosphorus and boron co-doped g-C3N4 for enhanced photocatalytic H2 production

Abstract

Solar water splitting by semiconductor photocatalysts has emerged as a favorable approach for green hydrogen production. Graphitic carbon nitride (g-C3N4) has gained substantial recognition amongst numerous semiconductor photocatalysts as a metal-free semiconductor with suitable band gap, appropriate band edge positions, and satisfactory photocatalytic activity for hydrogen production. However, its practical application is severely affected by high charge carrier recombination rate and inefficient visible light absorption. Introducing non-metal dopants into the g-C3N4 structure could suppress charge carrier recombination and tune the electronic property. Also, metal nanoparticles exhibit surface plasmon resonance (SPR) upon light interaction increasing the visible light absorption by the transport of hot electrons into the g-C3N4 framework. In this work, we report hybrid photocatalytic materials containing Ag-plasmonic metal and non-metal (B/P) dual heteroatom-doped g-C3N4 prepared via in-situ thermal polycondensation and succeeded by the photodeposition of Ag NPs. The structure of the prepared materials was studied through PXRD and FTIR spectroscopy; XPS was used for chemical analysis; SEM was used to study the morphology; and optical characteristics were studied through UV–Vis and PL spectroscopic techniques. The synergistic effects of SPR and heteroatom co-doping exhibit superior photocatalytic hydrogen production compared to pristine, B or P individual-doped, and B/P co-doped g-C3N4 samples. The optimized 1Ag/PBCN photocatalyst has demonstrated the highest photocatalytic hydrogen production rate of 1825 μmolh-1g−1, 18.3 times greater than g-C3N4. The modified hybrid material shows better activity due to the efficient charge carriers separation and extended visible light absorption. This work indicates that elemental co-doping and loading plasmonic nanoparticles on g-C3N4 to form hybrid nanocomposites may be a potential strategy to achieve better photocatalytic hydrogen evolution. The proposed methodology and outcomes will be helpful in the design and development of plasmon-enhanced hybrid photocatalysts for solar-driven green hydrogen production from water splitting.