Vertically aligned MoS2 thin film catalysts with Fe-Ni sulfide nanoparticles by one-step sulfurization for efficient solar water reduction

Abstract

• Transferable 2D/3D heterostructure catalysts synthesized via one-step sulfurization. • F1N9S/VMS/ p -Si exhibit excellent photocurrent density and lower onset potential. • No performance degradation during 10 h operation test for the F1N9S/VMS/ p -Si. • Scanning photoelectrochemical microscopy visualize photocurrents on photocathodes. Transferable 2-dimensional (2D) MoS 2 thin films have a versatile potential for constructing highly efficient photoelectrodes when combined with conventional semiconductor light absorbers, taking advantage of its optical transparency and high electrochemical activity. Here, we firstly report fully vertically aligned MoS 2 (VMS)/ p -Si heterostructure photocathode for photoelectrochemical (PEC) water splitting. Furthermore, 3D iron-nickel sulfide nanoparticles of tailored atomic composition are formed simultaneously during the synthesis of VMS via one-step sulfurization to build 3D/2D transition metal sulfide (TMD) heterostructure thin film catalyst. The spectroscopic results reveal that the Fe-doped Ni 3 S 2 nanoparticles on VMS/ p -Si photocathode induce the electrochemically-benign band bending in the overall heterostructure, enabling a significant improvement in PEC performance and long-term stability. Scanning photoelectrochemical microscopy is used to vividly visualize the photocurrent enhancement by the various 3D/2D TMD heterostructures. This work provides promising strategies in developing high performance TMD-based electrocatalysts for practical applications in a wide variety of electrochemical energy conversion processes.