Electroless plating synthesis of bifunctional crystalline/amorphous Pd-NiFeB heterostructure catalysts for boosted electrocatalytic water splitting

The rational design of low-cost and high-efficient electrocatalysts to overcome the energy barrier of water splitting has aroused great attentions. The amorphous-crystalline interface heterostructure has been verified to be a promising design for modulating the charge redistribution at interface active sites for promoting water splitting, which, however, remains a challenge. Herein, a bifunctional electrocatalyst with amorphous-crystalline heterostructures is fabricated by hybridizing amorphous NiFeB alloy and crystalline Pd nanoclusters on the nickel foam (NF) via a simple electroless plating strategy. The as-synthesized Pd-NiFeB/NF catalyst exhibits excellent HER and OER performance. Moreover, the assembled Pd-NiFeB/NF//Pd-NiFeB/NF electrolytic system requires a rather low cell voltage of 1.81 V to drive the durable current density of 500 mA cm⁻² for at least 100 h. Theoretical calculations reveal that the addition of Pd nanoclusters reduces the energy barriers for both HER and OER, which is due to the enhanced charge transfer and optimal adsorption of intermediates.