Improving Oxygen Reduction Reaction and Selective Hydrodechlorination Performance Based on CoNi on Graphene Using Ionic Liquids as a Binder

As a binder for the stabilization and dispersion of CoNi nanoparticles (NPs), ionic liquids (IL) were designed to connect inorganic anion on IL-functionalized reduced graphene oxide (rGO) and metal cation. The CoNi/IL-rGO described excellent oxygen reduction reaction (ORR) and the selective adsorption of bimetallic CoNi for chlorophene hydrodechlorination (HDC). The prepared electrocatalyst was characterized by SEM, TEM, XPS, Raman spectroscopy, XRD, and UV–vis spectroscopy. Results indicated that ILs could be functionalized by – stacking on the rGO surface. The optimal bimetallic CoNi NPs (Co-to-Ni weight ratio of 2.5:2.5) with small particles sizes (3.33 ± 0.03 nm) were uniformly dispersed on the surface of IL-rGO (mass ratio of IL:GO was 2:1) among a series of as-prepared catalysts. The IL on the rGO surface could prevent rGO agglomeration and provide sufficient binding sites to anchor the CoNi NPs via electrostatic interaction. Co(2.5)Ni(2.5)/IL(2)-rGO demonstrated low impedance (7.5 ) and diffusion resistance due to the introduction of IL. Co(2.5)Ni(2.5)/IL(2)-rGO exhibited a high peak current (–0.35 mA), preferred two-electron selectivity and high H2O2 productivity (>80%) toward ORR in an alkaline solution. The possible dechlorination mechanism of chlorophene was ascribed to the combination of adsorbed hydrogen on Co and adsorbed chlorophene on Ni.

Published in: "Journal of the Electrochemical Society".