Interfacial Engineering to Construct Antioxidative Pd4S/Pd3P0.95 Heterostructure for Robust Hydrogen Production at High Current Density

The design of highly efficient and stable electrocatalysts for large‐current‐density hydrogen evolution reactions (HER) is an urgent need for commercial industrial electrolyzers. Herein, a novel heterostructure in the form of Pd4S/Pd3P0.95 is constructed through interfacial engineering, which inherits the intrinsic merits of individual components and exposes active sites. Density functional theory (DFT) calculations indicate that the optimized heterostructure not only possesses the largest conductivity and adsorption energy for an oxygen atom, but also can significantly lower the kinetic energy barrier of water molecular dissociation. Accordingly, the optimized Pd4S/Pd3P0.95 heterostructure catalyst is promising for large‐current‐density HERs, requiring an overpotential of merely 284 and 387 mV to deliver an HER current density as high as 500 mA cm−2 in 0.5 m H2SO4 and 1 m KOH, respectively, which is superior to the benchmark 20% Pt/C (378 and 482 mV, respectively). Notably, the heterostructure catalyst runs smoothly to the current density of 1000 mA cm−2 with an overpotential of merely 538 and 486 mV in 0.5 m H2SO4 and 1 m KOH, respectively. Significantly, the heterostructure catalyst also exhibits fast reaction kinetics and remarkable long‐term durability. Moreover, the strong surface antioxidative ability is retained after a stability test in alkaline solution. An alloy‐type metal‐rich Pd4S/Pd3P0.95 heterostructure with strong antioxidative properties is constructed for large‐current‐density hydrogen production. The reduction of superficial localized oxidation and an electronic synergistic effect between Pd4S and Pd3P0.95 simultaneously enhances the hydrogen production process.