In-situ building of multiscale porous NiFeZn/NiZn-Ni heterojunction for superior overall water splitting
(1. Institute for Advanced Interdisciplinary Research (iAIR), University of Jinan, Jinan 250022, China;
2. School of Medical Information and Engineering, Southwest Medical University, Luzhou 646000, China)
2. School of Medical Information and Engineering, Southwest Medical University, Luzhou 646000, China)
Abstract: The development of efficient nonprecious bifunctional electrocatalysts for water electrolysis is crucial to enhance the sluggish kinetics of the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). A self-supporting, multiscale porous NiFeZn/NiZn-Ni catalyst with a triple interface heterojunction on nickel foam (NF) (NiFeZn/NiZn-Ni/NF) was in-situ fabricated using an electroplating-annealing-etching strategy. The unique multi- interface engineering and three-dimensional porous scaffold significantly modify the mass transport and electron interaction, resulting in superior bifunctional electrocatalytic performance for water splitting. The NiFeZn/NiZn-Ni/NF catalyst demonstrates low overpotentials of 187 mV for HER and 320 mV for OER at a current density of 600 mA/cm2, along with high durability over 150 h in alkaline solution. Furthermore, an electrolytic cell assembled with NiFeZn/NiZn-Ni/NF as both the cathode and anode achieves the current densities of 600 and 1000 mA/cm2 at cell voltages of 1.796 and 1.901 V, respectively, maintaining the high stability at 50 mA/cm2 for over 100 h. These findings highlight the potential of NiFeZn/NiZn-Ni/NF as a cost-effective and highly efficient bifunctional electrocatalyst for overall water splitting.
Key words: NiFeZn alloy; multiple interface; porous structure; dealloying; overall water splitting