Designing 1D Plasmonic Ag/CuWO4 Nanocomposite for Enhancing Visible-Light Photoelectrochemical Performance

We report the synthesis and characterization of CuWO4, its functionalization with plasmonic Ag nanostructures and its photoelectrochemical properties. First, a solution-phase polyvinylpyrrolidone (PVP)-assisted approach was used to prepare shape-controlled plasmonic Ag (nanoparticles (NPs) and nanowires (NWs)) via heterogeneous nucleation. The growth process and morphological tuning of the as-synthesized Ag nanostructures were investigated experimentally. Molecular dynamics (MD) simulations were used to understand the underlying principles that govern nanowire growth by analyzing the interaction energies between crystal surfaces and PVP as well as the atom density profile. Significant enhancements of the photocurrent (45% and 140%, respectively) at the thermodynamic potential for oxygen evolution (0.62 V vs Ag/AgCl) were obtained for Ag NP/CuWO4 (0.11 mA cm−2) and Ag NW/CuWO4 (0.18 mA cm−2) photoanodes, respectively, compared to pristine CuWO4 photoanode. Moreover, the incorporation of Ag NWs significantly enhances the incident photon to current conversion efficiency (IPCE) across the 350–550 nm spectral range, revealing a maximum around 10%. The obtained improvement is attributed to improved light harvesting by Ag-induced surface plasmon resonance (SPR) effects with a dual peak absorption, together with more effective charge carrier transfer/separation. Therefore, incorporation of the as-prepared plasmonic nanostructures with CuWO4 causes a considerable improvement of the photoelectrochemical activity for energy conversion/storage applications.