Facilitating the electrooxidation of 5-hydroxymethylfurfural on nickel hydroxide through deintercalation

The electrocatalytic of 5-hydroxymethylfurfural oxidation reaction (HMFOR) is an alternative route for the green production of valuable oxygenated chemicals. Nickel hydroxides, which consist of hydroxide layers and interlayer charge-balancing anions, are a type of promising catalysts for HMFOR. Progresses have been made on elucidating the correlation between the hydroxide layer and HMFOR performance, while the effect of intercalated anions on the activity remains unclear. Herein, two self-supported nickel hydroxide catalysts (i.e., pristine Ni(OH)₂/CP-F and deintercalated Ni(OH)₂/CP-A) are employed for revealing the relationship between anion-deintercalation and HMFOR activity. Physical characterizations demonstrate that the deintercalation phenomenon can alter the d-band center and increase the electron density of the Ni site. This endows the deintercalated Ni(OH)₂/CP-A with improved electrochemical properties (conversion = 99.99 %; FDCA yield > 99 %; FE > 99 %), enhanced adsorption strength for HMF, and increased intrinsic activity, compared to the pristine Ni(OH)₂/CP-F. This work not only reports an excellent HMFOR electrocatalyst, but also manifests the crucial effect of deintercalation on the electrochemical oxidation performance of Ni(OH)₂.