One Stone Two Birds: Unlocking the Synergy between Amorphous Ni(OH)2 and Pd Nanocrystals toward Ethanol and Formic Acid Oxidation

Even though extensive efforts have been devoted to mixing Pd nanocrystals with Ni(OH) 2 for the enhanced synergy, it remains a great challenge to incorporate nanosized Ni(OH) 2 species on the Pd electrode and reveal their synergy. Herein, we present spongelike Pd nanocrystals with the modification of amorphous Ni(OH) 2 species. The catalyst configuration is first considered by compositing Pd with Ni(OH) 2 species to optimize the Pd–Pd interatomic distance and then constructing a strongly coupled interface between Pd nanostructures and Ni(OH) 2 species. For the ethanol oxidation reaction (EOR) and the formic acid oxidation reaction (FAOR), Pd-Ni(OH) 2 composites exhibit an impressive mass activity of 4.98 and 2.65 A mg Pd –1, respectively. Most impressively, there is no significant decrease in the EOR activity during five consecutive cycles (50 000 s). A series of CO-poisoning tests have proved that the enhanced EOR and FAOR performances involve synergy between Pd nanostructures and Ni(OH) 2 species.