High-entropy type Fe-Ni-P-O-C amorphous Nanospheres: Remarkable Fe-ion migration induced efficient surface reconstruction for oxygen evolution reaction
Shiliu Yang, Xinhe Liu, Xunlu Wang, Yan Lin, Sina Cheng, Hongyang Gao, Fan Zhang, Li Li, Jiabiao Lian, Ulla Lassi, Ruguang Ma
Abstract
ABSTRACT Amorphous transition metal compounds ( a -TMC) become one of the most promising pre-catalysts toward oxygen evolution reaction (OER) due to their high-entropy nature and flexible self-reconstruction to highly active derivatives. However, the loosen bonds inside the amorphous structure make it an electronic insulator with unstable structure. Here, monodispersed Ni 2+ -phytate nanospheres implanted by Fe 3+ ions (NS FeNiPA ) were firstly prepared and subsequently transferred into homogeneous high-entropy type Fe-Ni-P-O-C amorphous nanospheres (CNS FeNiPO ). It is shown that the CNS FeNiPO presents robust structure and remarkable Fe ions migration during potential-driven activation process, which benefits efficient surface reconstruction and spherical morphology preservation. The CNS FeNiPO with low mass loading of 0.1 mg cm -2 could deliver small overpotential of 270 mV at 10 mA cm -2 and almost 100% retention of the initial current density after 10 h test. The improved electrocatalytic activity is attributed to the boosted electron transfer from Ni sites to O-containing intermediates by introduction of Fe and P atoms. Moreover, rechargeable Zn-air battery with CNS FeNiPO +Pt/C could achieve lower charge potential platform and better cycling performance than that with commercial RuO 2 +Pt/C. This work provides new insights into the design and understanding of high-entropy amorphous pre-catalysts toward OER.