Controllable Electron Distribution Reconstruction of Spinel NiCo₂O₄ Boosting Glycerol Oxidation at Elevated Current Density

Abstract

Electrocatalytic glycerol oxidation reaction (GOR) is an effective way to convert biomass byproduct to high value‐added chemicals, which; however, suffers from the low oxidation activity and conversion ratio of the presently available catalysts. Herein, the NiCo2O4/NF bimetallic oxide nanoarray is controllably fabricated by Ni substituting for octahedral Co3+ in Co3O4, which exhibits excellent GOR catalytic activity at elevated current densities (E300 = 1.42 V, E600 = 1.62 V) and overall Faradaic efficiency of 97.5% at 1.42 V (FEformic acid = 89.9% and FEglycolic acid = 7.62%). The high performance is attributed to the structure evolution including the rapid generation of NiIII‐OOH and CoIII‐OOH active species, the optimized intermediates adsorption, and the accelerated electron transfer owing to the Ni introduction, which are evidenced by the operando spectroscopy measurements and density functional theory calculations, respectively. The GOR/hydrogen evolution coupled two‐electrode electrolytic cell voltage is ≈299 mV lower than that of the water splitting at 50 mA cm−2. More importantly, compared to conventional water splitting, this electrolyzer is stable for over 200 h at 1.75 V, reducing energy consumption by 16.9% and obtaining high value‐added products at the anode concurrently.

Glycerol Electrolyzer with Graphite Anode and Cathode Produces Carbonyl Compounds and Hydrogen: Background Electrocatalysis of a “Nonparticipating” Current Collector

“…The comparison of the electrochemical parameters of the glycerol electrolyzer coupled to HER equipped with graphite with other systems equipped with metallic electrodes is illustrated in Table S5. The differences in electrolysis configuration, data collection, and units make comparing our data with the literature difficult, ,− but we may conjecture about some particular cases. For instance, the cell voltage of ∼1.0 V induces small amounts of carbonyl products at mmol L –1 , which increases with potential in all concentrations investigated here (Figure ), and H 2 is detected starting at 2.0 V of cell voltage (Figure ).…”

Sustainable Adipic Acid Production via Paired Electrolysis of Lignin-Derived Phenolic Compounds with Water as Hydrogen and Oxygen Sources

“…Since the first AA electrosynthesis (with a yield of 47%) via NiOOH electrodes under a current density of 6 mA cm –2 , great progress has been made in developing more efficient Ni-based catalysts, such as Ni­(OH) 2 and NiFe LDH. − Despite these efforts, the ECO of KA to AA still suffers from low current densities and production rates, limiting its industrial applications. Recently, Co-based spinel oxides, especially Co 3 O 4 , have been employed to promote efficient ECO of small molecules (e.g., 5-hydroxy-methylfurfural, glycerol) due to their unique e g orbital hybridization and rich 3d electron occupancies. − Our recent research also found that Co-based catalysts can achieve AA electrosynthesis . However, for pure Co 3 O 4 , its catalytic activity is relatively poor due to its weak adsorption and activation capacity for KA molecules.…”

Recent progress in transition metal based catalysts and mechanism analysis for alcohol electrooxidation reactions

“…Recent research efforts have been centered on the development of highly efficient and cost-effective electrocatalysts for glycerol oxidation reaction (GOR). A notable advancement in this area is the use of bimetallic electrocatalysts, exemplified by NiCo 2 O 4 / NF, investigated by Shi et al 110 This electrocatalyst, syn-…”

“…A notable advancement in this area is the use of bimetallic electrocatalysts, exemplified by NiCo 2 O 4 /NF, investigated by Shi et al . 110 This electrocatalyst, synthesized through hydrothermal and calcination processes, featured a distinctive 3D nanoneedle array structure, as shown in Fig. 10a and b.…”