▎ 摘　　要

NOVELTY - Making a transition metal catalyst comprises: (a) forming a slurry comprising carbon black particles and an aqueous solution comprising a salt of a transition metal M and an oxygen-containing chelating agent; (b) mixing the slurry, where the aqueous solution is absorbed by the carbon black particles; (c) separating the carbon black particles containing the absorbed solution from the non-absorbed solution; (d) drying the separated carbon black particles to obtain a solid product; and (e) heating the solid product, where a first portion of M is oxidized, a second portion of M is reduced to form nanoparticles comprising M1 and a carbon matrix comprising graphene forms and surrounds the nanoparticles to form the catalyst. USE - The method is useful for making a transition metal catalyst, which is used in an electrode and for catalyzing a hydrogen evolution reaction and/or an oxygen evolution reaction (all claimed). ADVANTAGE - The method is economical. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for: (1) a transition metal catalyst made by the method; (2) a transition metal catalyst comprising many nanoparticles, where each nanoparticle comprises both reduced and oxidized forms of a transition metal M and is encased in at least one layers of graphene; and (3) an electrode comprising the transition metal catalyst.