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Key Words:ORGANIC-COMPOUNDS; OXYGEN EVOLUTION; GLUCONIC ACID; OXIDATION; NICKEL; HYDROGEN; H-2
Abstract:Chemicals electrochemical refining coupled with cathode hydrogen production could effectively reduce the overpotential and energy cost. The electrooxidation cleavage of 1,4-glycosidic bond is the urgent problems for high-value D-glucaric acid (GRA) directly from the long-chain biomass saccharide composed of glucose. Hence, we investigated the oxidation path of the maltose over the alpha-Ni(OH)(2) as model electrocatalyst. The results showed that the cleavage potential of maltose 1,4-glycosidic bond is a little higher than that of the aldehyde/ hydroxyl groups in glucose, but much lower than that of water. Compared with water oxidation, the aldehyde/ hydroxyl groups oxidation could consume the Ni(OH)O intermediate so fast that it cannot accumulate. Operando electrochemical impedance spectroscopy (EIS) showed that the 1,4-glycosidic bond cleavage is not same to the aldehyde/hydroxyl groups oxidation reactions spontaneously, which occurs directly at an initial potential. The morphology of alpha-Ni(OH)(2) would be collapsed and high-priced nickel and metal-oxygen bond would be formed during water oxidation reaction, but which unchanged for glucose and maltose oxidation. In addition, the starch was also used as the long-chain saccharide to study the 1,4-glycosidic bond cleavage and the whole reaction path. This work promotes the development of green electrocatalytic systems to achieve sustainable valorization of biomass saccharide utilization pathways.
Volume:623
Issue:
Translation or Not:no