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

Abstract

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 mgPd–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.