Enhanced photoelectrochemical performance of hierarchical Ag/TiO₂/VGs composite films synthesized by dual-plasma synthesis

A ternary Ag/TiO₂/VGs composite film with a 3D conductive scaffold was successfully fabricated via a dual-plasma strategy combining helicon wave plasma CVD and RF magnetron sputtering. Vertically oriented graphene nanosheets (VGs) act as both high-surface-area conductive backbones and interfacial anchoring sites for TiO₂ and Ag nanoparticles. Structural analyses show anatase-phase TiO₂ and uniformly dispersed Ag nanoparticles, forming stable heterojunctions. UV–vis analysis reveals enhanced absorption (300–500 nm) and a reduced bandgap (2.6 eV) due to the synergistic effect of Ag and TiO₂. Electrochemical tests demonstrate that sample S60–100 exhibits the highest photocurrent and lowest interfacial charge transfer resistance, indicating efficient carrier separation and transport. A synergistic charge transfer mechanism is proposed, where the localized surface plasmon resonance (LSPR) of Ag enhances TiO₂ photoexcitation, and the Schottky barrier and conductive VGs network facilitate multistage electron transfer. This work underscores the advantages of dual-plasma interface engineering and offers a promising strategy for visible-light photocatalysis and advanced optoelectronic devices.