Photoelectrochemical Hydrogen Evolution Reaction in Heterojunction TMD Nanoscroll

The photoelectrochemical (PEC) hydrogen evolution reaction (HER) could produce carbon-neutral fuel from two of the planet’s most abundant resources – water and sunlight. However, a number of technical and economic challenges prevent the scalable use of conventional catalyst materials. The atomically thin 2D transition metal di-chalcogenides (TMDs) are emerging as promising catalysts because of their tunable electronic structure and unique mechanical properties. In particular, the rolling of 2D TMD nanosheets into 1D scrolls induces bending strain and produces a confinement for electronic and photonic interactions. The resulting heterojunctions produce strong internal fields and enhance photocarrier dissociation. This causes a 3-fold enhanced electrochemical performance compared to planar heterojunctions. Strain-induced modification of the band alignment in this quasi-1D MoS₂/WS₂ heterojunction nanoscrolls leads to a novel hybrid charge transfer process which helps in achieving a reduced Tafel value of 39 mV dec^-1, and an exchange current density up to 1.44 ×10^-4 Acm^-2, outperforming any 2D material catalyst.¹<br/>Reference:<br/>1. Ghosh, R., et al. “Enhancing the Photoelectrochemical Hydrogen Evolution Reaction through Nanoscrolling of Two-Dimensional Material Heterojunctions.” <i>ACS Nano</i> 2022, 16, 4, 5743–5751.