Surface engineering of hematite nanorods by 2D Ti3C2-MXene: Suppressing the electron-hole recombination for enhanced photoelectrochemical performance

Photoelectrochemical (PEC) water splitting is a promising approach to improve solar energy conversion, but still suffers from poor efficiency due to intrinsic high charge recombination and low conductivity of semiconductor photocatalysts. In this work, we applied Ti3C2-MXene to construct hematite/MXene nanorods (alpha-Fe2O3/MXene NRs) with enhanced PEC performance. The as-formed MXene-derived Ti-rich layer could not only serve as a passivation layer to significantly suppress surface electron-hole recombination, but also act as Ti source to promote bulk electron transfer. The optimum alpha-Fe2O3/MXene5/1 NRs resulted in a 7 times PEC enhancement compared with pristine alpha-Fe2O3 NRs while maintaining high stability. Mechanism studies by in-situ ultrafast transient absorbance spectra (TAS) directly proved that the duration of the photo-induced holes for optimum alpha-Fe2O3/MXene NRs was 10 times longer than pristine alpha-Fe2O3 NRs, proving notably enhanced surface charge separation. This study gives a clue to construct series of MXene based anode materials with promoted performance.

Automated summary

This study utilized Ti3C2-MXene to construct hematite/MXene nanorods, improving the efficiency of photoelectrochemical (PEC) water splitting. The optimized structure not only significantly enhanced PEC performance, but also maintained high stability, providing a new approach for constructing better anode materials in the future.