Electrochemically controlled CdS@CdSe nanoparticles on ITO@TiO2 dual core-shell nanowires for enhanced photoelectrochemical hydrogen production

摘要： Here, we report a novel dual heterostructured photoanode consisting of CdS@CdSe core-shell nanoparticles (NPs) and 1D-structure tin-doped indium oxide (ITO)@TiO2 core-shell nanowires (ITO@TiO2@CdS@CdSe) for highly efficient photoelectrochemical (PEC) hydrogen production. The finely controlled hierarchical core-shell CdS@CdSe sensitization from consecutive electrochemical deposition on the ITO@TiO2 core-shell nanowire has synergistic effects of visible-light utilization and efficient charge transport on the PEC response. The rationally designed dual core-shell heterostructure leads to cascade charge migration throughout the aligned energy band edges with rapid charge extraction through the hierarchical heterostructure of ITO@TiO2@CdS@CdSe, alleviating the crucial charge accumulation. As a result, the dual heterostructured photoanode exhibits a maximum photocurrent density of 20.11 mA/cm2 at 1.23 V vs. the reversible hydrogen electrode (RHE) and a dramatic enhancement in the incident photon-to-current efficiency (IPCE) over the extended absorption spectrum. The time-resolved photoluminescence (TRPL) characterization indicates the realized multiple-band cascade charge migration throughout ITO@TiO2@CdS@CdSe could promote an 8-fold increase in the charge separation efficiency. This rational design of dual-heterojunction-structured photoelectrodes via electrochemical deposition provides a demonstration of modifying conventional light-harvesting photoelectrodes with stagnate solar energy conversion and PEC hydrogen production.