H2O2-assisted fabricate nickel cobalt sulfide as the efficient catalyst for the novel strategy of 5-hydroxymethylfurfural stepwise electrolysis

Electrooxidation of 5‑Hydroxymethylfurfural (HMF) is considered a promising strategy for replacing the sluggish oxygen evolution reaction (OER) of electrolytic water, which can reduce the consumption of hydrogen production and the risk of gas mixing and obtain value-added products. Herein, a nanosheet with nanoflower catalyst (H-0.3Co-Ni3S2) was synthesized via a one-step hydrothermal process with the assistance of hydrogen peroxide (H2O2) for the electrooxidation of HMF. Adding H2O2 and Co can decrease Ni's outer layer electronic cloud density, which benefits the catalyst's oxidation and catalyzes the HMF electrooxidation. H-0.3Co-Ni3S2 shows the superior performance of the HMF electrochemical oxidation with the initial potential of 1.25 V vs. RHE and the voltage of 1.38 V vs. RHE at 200 mA cm−2 under the electrolyte of 1 M KOH with 10 mM HMF. The conversion rate, yield and Faraday efficiency of HMF electrooxidation for H-0.3Co-Ni3S2 in the electrolyte of 1 M KOH with 10 mM HMF are 98.2 %, 97.6 % and 97.6 %, respectively. Besides, we provide a novel stepwise electrolysis strategy that can inhibit OER effectively while electrolyzing large-concentration HMF rapidly. Finally, in an electrolyte of 1 M KOH with 30 mM HMF, the conversion rate, yield and Faraday efficiency achieve 100 %, 91.9 % and 97.4 %, respectively.