Hierarchical porous structured trimetallic non-oxides CoFeMo-A (A= P, Se) as electrocatalysts for oxygen evolution reaction

Abstract

In this work, a novel trimetallic non-oxides CoFeMo-A (A=P, Se) with hierarchical porous structure are prepared as the OER electrocatalysts, which are derived from layered double hydroxide (LDH) using zeolitic imidazolate framework-67 (ZIF-67) as the precursor. The prepared CoFeMo-A (A=P, Se) show the rough, loose and hierarchical porous feature, which is beneficial to improve the mass transfer efficiency and the exposure of more active sites. Besides, the electronic configuration of the metals is tuned owing to the incorporation of P and Se and in return the kinetics of OER process is accelerated. Additionally, the LDH derived CoFeMo-A (A=P, Se) can be in situ transformed to the more reactive CoFeMo-oxyhydroxide during the OER process. Benefiting from the above-mentioned advantages, CoFeMo-A (A=P, Se) exhibit excellent electrocatalytic activity for OER with a low overpotential of 273 and 299 mV to achieve a current density of 10 mA cm−2 and the low Tafel slope of 31.2 and 39.5 mV dec−1for CoFeMo-P and CoFeMo-Se, respectively. The slight difference in OER performance is mainly due to the different crystallinity and intrinsic activity. The work provides a promising strategy to improve the catalytic activity of electrocatalysts by preparing multi-metal non-oxides based on the MOF-derived LDH.