(FeSe<sub>2</sub> + CoSe<sub>2</sub>) Nanoparticles Anchored on 3D Porous Ultrathin Carbon Nanosheets for High-Activity Oxygen Evolution Reaction
Hui Li, Haonan Xie, Xixi Wang, Enzuo Liu, Jianli Kang, Chunsheng Shi, Junwei Sha, Liying Ma
Abstract
Since the sluggish kinetics of the oxygen evolution process (OER) at the anode of water splitting remains to be a crucial bottleneck for hydrogen production, it is imperative to develop low-cost OER electrocatalysts with high efficiency. Here, (FeSe 2 + CoSe 2 ) nanoparticles loaded on nitrogen-doped three-dimensional porous carbon nanosheets (referred to as (FeSe 2 + CoSe 2 )/N-3DCN) were prepared by freeze-drying, heat treatment and selenization. The favorable affinity and large surface area of N-3DCN enabled the synthesis of the ultrafine (FeSe 2 + CoSe 2 ) nanoparticles with a diameter of 10 nm, which were highly dispersed on carbon nanosheets and provided a significant number of active sites. The density functional theory (DFT) calculation demonstrated that the free energy of oxygen-containing intermediates during OER was optimized by coupling FeSe 2 with CoSe 2 . The overpotential of (FeSe 2 + CoSe 2 )/N-3DCN is 312 mV at 10 mA cm –2, which is superior to those of (FeSe 2 + CoSe 2 ) (390 mV), CoSe 2 /N-3DCN (377 mV), RuO 2 (320 mV), and FeSe 2 /N-3DCN (479 mV). Additionally, after the 80 h stability test, the overpotential of (FeSe 2 + CoSe 2 )/N-3DCN can still be maintained at 316 mV.