Production and Properties of Ni–Pt/C Composites with a Sapropelic Coal Matrix

Abstract— Activated sapropelic coal is proposed as the matrix for the creation of the catalytic composite Ni–Pt/C, which is generally obtained by applying Ni–Pt nanoalloy particles to a highly porous carbon support. Both immobilized and free Ni–Pt particles are considered. X-ray phase analysis shows that the reduction of the precursors Ni(II) and Pt(IV)—in the form of the complex [PtCl₆]^2–—by an alkaline hydrazine hydrate solution yields two products: particles of a solid solution based on an fcc structure containing ∼10 at % nickel; and pure nickel particles. The carbon carrier employed determines the composition and structure of the nanoparticles formed at the surface. In particular, the nickel content in the solid solution increases to ∼50 at %; and the NiPt intermetallic phase is formed directly as crystals of L1₀ structure. The gas mixture formed in catalytic decomposition of the hydrazine hydrate solution at the surface of the Ni–Pt/C composite consists mainly of nitrogen (77%); the remainder is hydrogen (23%).