Coupling NiSe₂ Nanoparticles with N-Doped Porous Carbon Enables Efficient and Durable Electrocatalytic Hydrogen Evolution Reaction at pH Values Ranging from 0 to 14

Integrating metal-based species with a carbon matrix is a promising approach for fabricating inexpensive, durable, and efficient electrocatalysts. Herein, NiSe 2 -decorated and N-doped carbon polyhedra (NC) are prepared as electrocatalysts for hydrogen evolution reaction (HER) by a template-assisted approach. The optimal NC-NiSe 2 delivers extraordinary catalytic activities toward HER in a wide pH range, with overpotentials of 127 mV in 0.5 M H 2 SO 4, 226 mV in 1 M PBS, and 205 mV in 1 M KOH to drive a current density of 10 mA cm –2 . In addition, this catalyst undergoes fast reaction kinetics via a Volmer–Heyrovsky mechanism and exhibits excelent long-term catalytic durability for 48 h in the full pH media. During electrocatalysis, when electrons pass through the NC matrix to the surface of NiSe 2 particles, water molecules at the active sites of NiSe2 are reduced, and then hydrogen is released. The excellent catalytic activity and durability mainly benefit from the hierarchically porous architecture as well as the synergistic interaction of NiSe 2 nanoparticles and NC matrix, which not only significantly boost the electronic conductivity and generate plentiful active sites but also guarantee the chemical and structural stabilities of NiSe 2 catalytic species. This work unravels deep insights into the exploration of carbon-supported metal chalcogenides as highly efficient HER electrocatalysts at full-pH values.