Stable Pd-Cu Hydride Catalyst for Efficient Hydrogen Evolution.

Pd has been regarded as one of the alternatives to Pt as a promising hydrogen evolution reaction (HER) catalyst. Strategies including Pd-metal alloys (Pd-M) and Pd hydrides (PdH x ) have been proposed to boost HER performances. However, the stability issues, e.g., the dissolution in Pd-M and the hydrogen releasing in PdH x , restrict the industrial application of Pd-based HER catalysts. We here design and synthesize a stable Pd-Cu hydride (PdCu 0.2 H 0.43 ) catalyst, combining the advantages of both Pd-M and PdH x structures and improving the HER durability simultaneously. The hydrogen intercalation is realized under atmospheric pressure (1.0 atm) following our synthetic approach that imparts high stability to the Pd-Cu hydride structure. The obtained PdCu 0.2 H 0.43 catalyst exhibits a small overpotential of 28 mV at 10 mA/cm 2 , a low Tafel slope of 23 mV/dec, and excellent HER durability due to its appropriate hydrogen adsorption free energy and alleviated metal dissolution rate.