Direct Thermal Enhancement of Hydrogen Evolution Reaction of On-Chip Monolayer MoS₂

MoS₂ has drawn great attention as a promising alternative to Pt-based catalysts for the hydrogen evolution reaction (HER). However, it suffers from sluggish kinetics to drive the HER process because of inert basal planes. Here, an on-chip MoS₂ monolayer (MoS₂ ML) HER reactor was designed and fabricated to reveal direct thermal enhancement of MoS₂ ML for the HER. The thermal effects generated efficient electron transfer in the atomic MoS₂ ML and at the interface between the electrolyte and the catalyst, leading to enhanced HER activity. The MoS₂ ML measured at a higher temperature (60 °C) possesses a significantly enhanced HER activity with a lower overpotential (90 mV at current densities of 10 mA cm^-2), lower Tafel slope (94 mV dec^-1), and higher turnover frequency (73 s^-1 at an overpotential of 125 mV) compared to the results obtained at room temperature. More importantly, the findings are attractive toward understanding the thermal effect on 2D monolayers as well as the development of next-generation electrocatalysts.