Pd@CuInP2S6 Core–Shell Nanospheres with Exceptional Hydrogen Evolution Capability and Stability in Both Alkaline and Acidic Media under Large Current Density Exceeding 1000 mA cm−2

Abstract By combining Pd with 2D layered crystal CuInP 2 S 6 (CIPS) via laser irradiation in liquids, low‐loading Pd@CIPS core–shell nanospheres are fabricated as an efficient and robust electrocatalysts for HER in both alkaline and acidic media under large current density (⩾1000 mA cm −2 ). Pd@CIPS core–shell nanosphere has two structural features, i) the out‐shell is the nanocomposite of PdH x and PdInH x , and ii) there is a kind of dendritic structure on the surface of nanospheres, while the dendritic structure porvides good gas desorption pathway and cause the Pd@CIPS system to maintain higher HER activity and stability than that of commercial Pt/C under large current densities. Pd@CIPS exhibits very low overpotentials of −218 and −313 mV for the large current density of 1000 mA cm −2 , and has a small Tafel slope of 29 and 63 mV dec −1 in 0.5 m H 2 SO 4 and 1 m KOH condition, respectively. Meanwhile, Pd@CIPS has an excellent stability under −10 and −500 mA cm −2 current densities and 50 000 cycles cyclic voltammetry tests in 0.5 m H 2 SO 4 and 1 m KOH, respectively, which being much superior to that of commercial Pt/C. Density functional theory (DFT) reveals that engineering electronic structure of PdH x and PdInH x nanostructure can strongly weaken the Pd─H bonding.