Ni2p-Nise2 Heterostructure Aerogel for Highly Efficient Electrocatalytic Hydrogen Evolution and 5-Hydroxymethylfurfural Oxidation

Green hydrogen prepared by the cathodic hydrogen evolution reaction (HER) of renewable energy water electrolysis is one of the best choices for future energy. However, the anodic oxygen evolution reaction (OER) with high theoretical potential limits the efficiency of overall water splitting. Herein, a bifunctional Ni2P-NiSe2 heterostructure aerogel (Ni-P-Se aerogel) was constructed to boost HER and replace OER by 5-hydroxymethylfurfural oxidation reaction (HMFOR) to produce high-valued 2,5-furandicarboxylic acid (FDCA) with low operating voltage and high conversion. The NiSe2 with cubic pyrite-type crystal structure was favor for anodic reconstruction, which allowed the effective generation of activated oxygen species and further promoted HMFOR. Moreover, the coupling of Ni2P modulated the adsorption energy of OH- in HMFOR and enhanced the activity toward HER. Besides, the aerogel structure with porous network structure provides abundant active sites and mass-transfer pathways. Benefit from these advantages, the optimized Ni-P-Se aerogel exhibited high HER performance (68 mV at 10 mA·cm-2), low onset oxidation potential (1.30 V) and high Faradaic efficiency (97.4%) and FDCA production rate (99.2 μmolFDCA·h-1·cm-2) of HMFOR. Compared to OER, the two-electrode system coupled with HMFOR had significantly increased current density at low operating voltage (87 mA·cm-2 increase at 1.50 V), proving the superiority of HMFOR as alternative anodic reaction. This work offers an anticipated perspective of bifunctional electrocatalysts toward the combination of HER and organics oxidation.