▎ 摘　　要

NOVELTY - A polyelectrolyte (PEM) water electrolysis hydrogen evolution reaction catalyst comprises a carrier; and ternary alloy particles which are supported in the carrier, and include platinum (Pt), scandium (Sc) and lanthanum (La). USE - A polyelectrolyte (PEM) water electrolysis hydrogen evolution reaction catalyst for PEM water electrolysis system (claimed). ADVANTAGE - The catalyst is capable of reducing the cost of hydrogen generation reaction catalyst in the process of the PEM water electrolysis technology. The catalyst has improved durability and catalytic activity. DETAILED DESCRIPTION - A polyelectrolyte (PEM) water electrolysis hydrogen evolution reaction catalyst comprises a carrier; and ternary alloy particles which are supported in the carrier, include platinum (Pt), scandium (Sc) and lanthanum (La) and have formula Pt3ScxLa1-x (1). INDEPENDENT CLAIMS are included for: (1) PEM water electrolysis system comprising cathode comprising PEM water electrolysis hydrogen generation reaction catalyst; anode; and PEM, where a first reaction equation is performed in the negative electrode, a second reaction equation is performed in the positive electrode, and PEM is oxygen gas generated in the positive electrode and generated in the negative electrode in which hydrogen gas is separated and hydrogen ions generated from the anode can move to the cathode; and (2) preparing PEM water electrolysis hydrogen generation reaction catalyst which involves dispersing a support in a solvent; preparing a precursor mixture by adding Pt, Sc, and La metal precursors to the solvent in which the support is dispersed; and reducing the metal precursor by irradiating the precursor mixture with an electron beam.