Thermally driven morphology and lattice transformation of NiCo alloy for accelerating electrocatalytic water splitting

Abstract

In the water-splitting process, the OER is a slow four-electron transfer process, and the overall efficiency of the water-splitting performance is low. A large reaction activation energy is thus required to overcome the high reaction energy barrier. To address this issue, we adjusted the external environment to provide thermal assistance, which increased the catalyst activity. Thermal assistance reduced the HER or OER overpotential of the Ni : Co = 1.5 : 1 catalyst during water electrolysis, achieving an HER overpotential of 48 mV and an OER overpotential of 296 mV at 10 mA cm⁻² at 60 °C. The results reveal changes in both the morphology and crystal phase during the reaction. When the temperature was returned to 20 °C after heating, the activity of the catalyst was significantly higher than that before the temperature rise due to changes in the morphology and lattice.