Ginkgo Leaf‐Derived Carbon Supports for the Immobilization of Iron/Iron Phosphide Nanospheres for Electrocatalytic Hydrogen Evolution
Qichang Wang, Zhaofu Fei, Dekui Shen, Chongbo Cheng, Paul J. Dyson
Abstract
Abstract Iron/iron phosphide nanospheres supported on ginkgo leaf‐derived carbon (Fe&FeP@gl‐C) are prepared using a post‐phosphidation approach, with varying amounts of iron (Fe). The activity of the catalysts in the hydrogen evolution reaction (HER) outperforms iron/iron carbide nanospheres supported on ginkgo leaf‐derived carbon (Fe&Fe x C@gl‐C), due to enhanced work function, electron transfer, and Volmer processes. The d‐band centers of Fe&FeP@gl‐C‐15 move away from the Fermi level, lowering the H 2 desorption energy and accelerating the Heyrovsky reaction. Density functional theory (DFT) calculations reveal that the hydrogen‐binding free energy |ΔG H* | value is close to zero for the Fe&FeP@gl‐C‐15 catalyst, showing a good balance between Volmer and Heyrovsky processes. The Fe&FeP@gl‐C‐15 catalyst shows excellent hydrogen evolution performance in 0.5 m H 2 SO 4 , driving a current density of 10 mA cm −2 at an overpotential of 92 mV. Notably, the Fe&FeP@gl‐C‐15 catalyst outperforms a 20 wt% Pt/C catalyst, with a smaller overpotential required to drive a higher current density above 375 mA cm −2 .