High loading of NiFe active sites on a melamine formaldehyde carbon-based aerogel towards efficient bi-functional electrocatalysis for water splitting

Abstract

Compared with precious metals, base metals have large abundance in the earth's crust and a much lower price. Thus, the research and development of base metal-based catalysts focus on improving the performance of catalysts with less consideration of the influence of metal content on the cost. Herein, we report the synthesis and catalysis properties of two base metal (Ni and Fe) catalysts supported by a high nitrogen containing carbon aerogel. A melamine formaldehyde (MF) aerogel was used as a support, and high concentration of Ni²⁺/Fe³⁺ metal ions were in situ implanted into the three-dimensional network of gels in the sol–gel process. The high metal loading of 43 wt% provided adequate active sites for the catalytic process. The high N content of 11.3 wt% in MF aerogels also improved the surface structure effect of the catalysts during the catalytic process. The prepared aerogel-based catalysts exhibited enhanced catalytic activity for both the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER). The two-electrode system for water splitting, with prepared samples as the anode and the cathode, exhibited a current density of 10 mA cm⁻² at 1.63 V. This high loading and high yield catalyst synthesis method provides a new potential way for the synthesis of functional catalysts.