Controlled Synthesis and Photoelectrochemical Performance Enhancement of Cu2-xSe Decorated Porous Au/Bi2Se3 Z-Scheme Plasmonic Photoelectrocatalyst

In this paper, uniform Cu2-xSe-modified Au/Bi2Se3 hybrid nanoparticles with porous shells have been prepared through a cation exchange method. Bi2Se3/Cu2-xSe Z-scheme heterojunction is introduced onto Au nanocube by replacing Bi3+ with Cu2+. Owing to the effective coupling between Au core and semiconductor shells, Au/Bi2Se3/Cu2-xSe hybrids present a broad and strong plasmon resonance absorption in the visible band. More intriguingly, the carrier lifetime of Au/Bi2Se3/Cu2-xSe hybrid photoelectrodes can be further tailored with corresponding Cu2-xSe content. Through parameter optimization, 0.1-Au/Bi2Se3/Cu2-xSe electrode exhibits the longest electron lifetime (86.03 ms) among all the parallel samples, and corresponding photoelectrochemical performance enhancement is also observed in the tests. Compared with that of pure Bi2Se3 (0.016% at 0.90 V vs. RHE) and Au/Bi2Se3 (0.02% at 0.90 V vs. RHE) nanoparticles, the maximum photoconversion efficiency of porous Au/Bi2Se3/Cu2-xSe hybrid photoanodes increased by 5.87 and 4.50 times under simulated sunlight illumination, attributing to the cooperation of Z-scheme heterojunction and plasmon resonance enhancement effects. All the results indicate that Au/Bi2Se3/Cu2-xSe porous hybrids combine eco-friendliness with excellent sunlight harvesting capability and effectively inhibiting the charge recombination, which provide a new idea for efficient solar-driven water splitting.