High Entropy Alloy Electrocatalytic Electrode toward Alkaline Glycerol Valorization Coupling with Acidic Hydrogen Production

Abstract

Electrochemical glycerol oxidation reaction (GOR) is an attractive alternative anodic reaction to oxygen evolution reaction for a variety of electrolytic synthesis, thanks to the possibility of mass production of glycerol from biomass and the relative low thermodynamic potential of GOR. The development of high-activity cheap electrocatalysts toward GOR yet faces a daunting challenge. Herein, we experimentally prepare a new range of high entropy alloy (HEA) self-supported electrodes with uniform HEA nanoparticles grown on carbon cloth. The systematic electrochemical studies verify that the HEA-CoNiCuMnMo electrode exhibits attractive performance for GOR electrocatalysis with low overpotential and high selectivity toward formate products. The surface atomic configurations of HEA-CoNiCuMn-Mo are studied by a self-developed machine learning-based Monte Carlo simulation, which points out the catalytic active center to be Mo sites coordinated by Mn, Mo, and Ni. We further develop a hybrid alkali/acid flow electrolytic cell by pairing alkaline GOR with acidic hydrogen evolution reaction using the HEA-CoNiCuMnMo and the commercial RhIr/Ti as the anode and the cathode, respectively, which only requires an applied voltage of 0.55 V to reach an electrolytic current density of 10 mA cm −2 and maintains long-term electrolysis stability over 12 days continuous running at 50 mA cm −2 with Faraday efficiencies of over 99% for H 2 in the cathode and 92% for formate production in the anode.

Ru-doping induced lattice strain in hetero-phase Ni2P–Ni12P5arrays enables simultaneous efficient energy-saving hydrogen generation and formate electrosynthesis

“…Moreover, the glycerol oxidation reaction (GOR) is thermodynamically more favorable in comparison with the OER, making it an ideal alternative to replace the OER to assemble hybrid water electrolysis systems with low operating cell voltage. [13][14][15][16] Selectivity control is essential in the electrocatalytic GOR, not only to avoid the generation of greenhouse gases (CO 2 from the complete oxidation of glycerol) but also to obtain selective value-added products. 17,18 To construct hybrid water electrolysis systems with highefficiency hydrogen production and low energy consumption, the development of bifunctional high-performance electrocatalysts with low cost is of vital signicance.…”

“…Moreover, the glycerol oxidation reaction (GOR) is thermodynamically more favorable in comparison with the OER, making it an ideal alternative to replace the OER to assemble hybrid water electrolysis systems with low operating cell voltage. 13–16 Selectivity control is essential in the electrocatalytic GOR, not only to avoid the generation of greenhouse gases (CO 2 from the complete oxidation of glycerol) but also to obtain selective value-added products. 17,18…”

The effect of the hydroxyl group position on the electrochemical reactivity and product selectivity of butanediol electro-oxidation

“…In recent decades, the electro-oxidation of small molecule alcohols has been studied extensively due to the interest in the potential as raw materials for electro-synthesis of value-added chemicals and alternative reaction of oxygen evolution reaction (OER) for H 2 cogeneration. [1][2][3][4][5] The electro-oxidation of alcohols has been investigated on both noble metal, [6][7][8] non-noble metal-based, 9,10 and their hybrid electrodes. [11][12][13] A number of studies have been focused on improving the catalytic activity of electrodes as well as reducing the mass loading of noble metals.…”

Energy-saving H2 production from a hybrid acid/alkali electrolyzer assisted by anodic glycerol oxidation

“…In recent years, hybrid acid/alkali electrolyzers with the anode in an alkaline electrolyte and the cathode in an acid electrolyte have been confirmed to greatly reduce the applied voltage of the electrolysis system due to the assistance of electrochemical neutralization energy, an energy formed by electrochemically neutralizing the acid and base by consuming H + and OH − at the cathode and anode, respectively. [28][29][30][31][32] In addition, such a hybrid acid/alkali electrolytic system may provide an adjustable pH environment for anodic and cathodic reactions. Therefore, assembling a hybrid acid/alkali electrolyzer will be conducive to lowering the electrical energy required and enhancing the kinetics.…”