The HMF (5-Hydroxymethylfurfural) oxidation was conducted on CuO electrocatalyst made by the solution-based method. In CuO electrocatalyst, the HMF was preferred to be oxidized than OER as the primary competing reaction for the HMF electrocatalytic oxidation. The onset potential for HMF oxidation was about 1.40 V vs. RHE, while OER’s is 1.60 V vs. RHE. The reaction pathway of HMF oxidation was purposed by HPLC, including side reactions such as degradation or polymerization and Cannizzaro reaction, which performed in the alkaline electrolyte (pH 13). In lower applied potential, the selectivity of DFF reached the highest value (at 1.40 V vs. RHE is about 40%). The DFF selectivity can be increased by preventing the side reaction to occur. The selectivity of DFF on CuO is increased from about 40% to about 60% by changing the pH value of electrolyte from 13 (0.1 M KOH) into 9.6 (0.1 M Na2B4O7) with loss its current only 10.87% after 5 hours reaction. Moreover, in this study, the yield of DFF can be increased six times by changing the reactant (HMF) concentration. Furthermore, the different annealing process can influence the morphology of CuO, which increases the surface area and promotes more HMF oxidation reaction to occur with the current and DFF’s yield increase two times with a good stability.

The HMF (5-Hydroxymethylfurfural) oxidation was conducted on CuO electrocatalyst made by the solution-based method. In CuO electrocatalyst, the HMF was preferred to be oxidized than OER as the primary competing reaction for the HMF electrocatalytic oxidation. The onset potential for HMF oxidation was about 1.40 V vs. RHE, while OER’s is 1.60 V vs. RHE. The reaction pathway of HMF oxidation was purposed by HPLC, including side reactions such as degradation or polymerization and Cannizzaro reaction, which performed in the alkaline electrolyte (pH 13). In lower applied potential, the selectivity of DFF reached the highest value (at 1.40 V vs. RHE is about 40%). The DFF selectivity can be increased by preventing the side reaction to occur. The selectivity of DFF on CuO is increased from about 40% to about 60% by changing the pH value of electrolyte from 13 (0.1 M KOH) into 9.6 (0.1 M Na2B4O7) with loss its current only 10.87% after 5 hours reaction. Moreover, in this study, the yield of DFF can be increased six times by changing the reactant (HMF) concentration. Furthermore, the different annealing process can influence the morphology of CuO, which increases the surface area and promotes more HMF oxidation reaction to occur with the current and DFF’s yield increase two times with a good stability.

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