High-performance photoelectrochemical cells with MoS2 nanoflakes/TiO2 photoanode on 3D porous carbon spun fabric

Abstract

A solar-driven photoelectrochemical (PEC) cell is emerging as one of the promising clean hydrogen generation systems. Engineering of semiconductor heterojunctions and surface morphologies of photoelectrodes in a PEC cell has been a primitive approach to boost its performance. This study presents that a molybdenum disulfide (MoS₂) nanoflakes photoanode on 3-dimensional (3D) porous carbon spun fabric (CSF) as a substrate effectively enhances hydrogen generations due to sufficiently enlarged surface area. MoS₂ is grown on CSFs utilizing a hydrothermal method. Among three different MoS₂ coating morphologies depending on the amount of MoS₂ precursor and hydrothermal growth time, film shape MoS₂ on CSFs had the largest surface area, exhibiting the highest photocurrent density of 26.48 mA/cm² and the highest applied bias photon-to-current efficiency (ABPE) efficiency of 5.32% at 0.43 V_RHE. Furthermore, with a two-step growth method of sputtering and a subsequent hydrothermal coating, continuous TiO₂/MoS₂ heterojunctions on a porous CSF further promoted the photoelectrochemical performances due to their optimized bandgap alignments. Enlarged surface area, enhanced charge transfer, and utilization of visible light enable a highly efficient MoS₂/TiO₂/CSF photoanode with a photocurrent density of 33.81 mA/cm² and an ABPE of 6.97 % at 0.87 V_RHE. The hydrogen generation amount of the PEC cell with MoS₂/TiO₂/CSF photoanode is 225.4 μmol/L after light irradiation of 60 s.