De-alloyed non-noble Fe-based alloy for hydrogen evolution reaction

Abstract

The high cost of noble metal raw materials is a major limitation to the production of hydrogen from electrocatalytic water splitting. Nowadays, the poor activity and complex synthesis methods of non-noble electrocatalysts need to be urgently improved. Herein, we prepared the Fe-Si-B alloys with nanosheet structure on the surface by de-alloying process in KOH solution. Experimental results indicate that there are lots of B-doped Fe nanosheets on the surface due to the faster dissolution rate of Fe-Si phase in the alkaline solution. The small amounts of boron remaining and the oxidation of the Fe nanosheets could enhance the activity of the hydrogen evolution reaction (HER). The HER overpotential under 10 mA/cm² is 214 mV. The coordination between elemental components and the de-alloying process not only increased the electrochemical surface area, but also enhanced electrocatalytic activity of iron atoms. This work provides a new idea for the design of Fe-based electrocatalysts.