Plasmonic gold nanorods decorated Ti3C2 MXene quantum dots-interspersed nanosheet for full-spectrum photoelectrochemical water splitting

Abstract

Efficient utilization of solar energy for economical photoelectrochemical (PEC) water splitting requires highly active and stable photoelectrodes with the abilities of harvesting broadband light from ultraviolet to infrared. Herein, we report on the synthesis and characterization of plasmonic gold nanorods (NRs) in situ decorated onto the Ti3C2 MXene quantum dots-interspersed Ti3C2 nanosheet (TDTS) as well as their implementation as photoanodes for full-spectrum solar-light-activated PEC water splitting. The TDTS is prepared by a hydrothermal method, followed the plasmonic Au NRs chemically anchored on the surface of TDTS via a seed growth method. Under the illumination of simulated solar light (100 mW cm−2), the optimized Au NRs/TDTS hybrid composite displays a stable and remarkable gas production rate that is about 3.4 times higher than that of pristine TDTS, and broadened spectral response range of 300–1100 nm. Such high performance arises from the generating strong plasmon-induced hot electrons of Au NRs that inject into TDTS with efficient charge separation and transfer at the interface. X-ray photoelectron spectroscopy and femtosecond time-resolved transient absorption measurements provide direct evidences that the plasmon-induced interfacial hot electrons could efficient transfer from Au to TDTS with the quantum efficiency of 16 ± 5%. This strategy provides an avenue for designing plasmon-mediated composite systems to effectively harvest full-spectrum solar light conversion into chemical energy.