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 VRHE. 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 VRHE. The hydrogen generation amount of the PEC cell with MoS2/TiO2/CSF photoanode is 225.4 μmol/L after light irradiation of 60 s.

Keywords

• Photoelectrochemical cell
• Photoanode
• MoS2
• TiO2
• 3D porous carbon spun fabric
• Conformal coating