Organic phosphoric acid induced coral-like palladium network nanostructures for superior polyhydric alcohols electrocatalysis

In this work, coral-like palladium (Pd) network nanostructures were successfully synthesized using a facile solvothermal method assisted by 1-hydroxyethylidene-1,1-diphosphonic acid (HEDP). The coral-like Pd network nanostructures exhibited a concave middle and two-sided morphology nanostructure in detail, which provided more Pd active sites that facilitated the polyhydric alcohols electrooxidation reaction. The synthesized coral-like Pd network nanostructures showed excellent mass activity (1785 mA mg−1) and specific activity (8.81 mA cm−2) for ethylene glycol oxidation at peak potential, which was 4.0 times and 2.2 times higher than that of commercial Pd black (427 mA mg−1 and 4.00 mA cm−2), respectively. Meanwhile, with unique network structures and organic phosphoric acid modification, the coral-like Pd network nanostructures also exhibited superior activity for glycerol oxidation. After 7200 s testing, the coral-like Pd network nanostructures further displayed excellent durability for ethylene glycol and glycerol oxidation with the mass activity remaining 82.40 % and 85.79 %, respectively. The DFT calculations demonstrated that phosphorus (P) modified on coral-like Pd network nanostructures could upshift the Pd d-band center, which could promote the adsorption and activation of H2O and the oxidation/removal of COads and –COHx species, improving the complete oxidation of polyhydric alcohols.