Magnetic field enhanced surface activity of ferromagnetic Cr2Ge2Te6 nanosheets for electrocatalytic oxygen evolution reaction

Abstract

Two-dimensional materials as excellent candidates for noble metal electrocatalysis still face great challenges in the practical application of efficient water electrolysis. Recent reports have shown that applying external fields (such as magnetic field, light field, etc.) is a simple and effective strategy to improve the electrocatalytic water splitting performance of non-precious metal catalysts. In this work, we systematically studied the electrocatalytic oxygen evolution performance of magnetic Cr2Ge2Te6 nanosheets through a series of strategies. Firstly, the number of layers of Cr2Ge2Te6 nanosheets was reduced by liquid exfoliation, and the active specific surface area was increased, which effectively improved the electrocatalytic oxygen evolution reaction (OER) performance of Cr2Ge2Te6 nanosheets. Subsequently, the electrocatalytic performance of Cr2Ge2Te6 nanosheets was further enhanced by the application of external magnetic field. The current density of 10 mA/cm2 corresponds to an overpotential of 231 mV and a Tafel slope as low as 64.1 mV/dec. Combined with the electrochemical impedance spectroscopy (EIS) and the analysis of the electrochemcial active surface area (ECAS), the Lorentz force generated by magnetic field and the local heating induced by alternating magnetic field can improve the charge transfer efficiency in the electrocatalytic process, thus improving the performance of electrocatalytic oxygen evolution.