The identification of dual active routes for highly efficient furfural oxidation reaction coupling with hydrogen production over Re modulated Co(OH)₂/CC

It is of great significance and challenge to tune the active sites of two-dimensional materials and identify the exclusive active sites for separate reaction toward hydrogen evolution reaction (HER) coupled with electrochemical oxidation (ECO) reaction. Herein, Re was introduced to tune d band charge density of Co, which reduced the energy barrier of water splitting for HER. Meanwhile, the abundant oxygen vacancies (O_v) caused by Re introduction resulted in a new reaction route for furfural oxidation reaction (FOR). That is, the adsorbed OH⁻ on O_v accelerates the dehydrogenation of Co(OH)O, and the active site further promotes the nucleophile dehydrogenation, thus improving the catalytic performance of FOR. In conclusion, Re-Co(OH)₂/CC with Re modified Co-centered sites displays dual active routes, which simultaneously enhance FOR and HER with a cell voltage (1.36 V) at 10 mA cm⁻², surpassing the most two-dimensional transition-metal hydroxides (2D TMHs) results reported as we known. This work provides new insights into the modulation of Co electronic structure and O_v concentration, which results in enhanced bifunctional electrocatalytic reactions.