▎ 摘　　要

NOVELTY - Nanocomposite material for use in catalyzing a hydrogen evolution reaction (HER), comprises a nanosheet comprising a metal chalcogenide, and a carbonaceous substrate supporting the nanosheet. The carbonaceous material is selected from graphene and reduced graphene oxide (r-GO). USE - The nanocomposite material is useful for catalyzing HER (claimed), where the hydrogen is used as a green energy carrier. ADVANTAGE - The nanocomposite material has high catalytic activity, and provides higher current densities at low overpotentials in an acidic medium. DETAILED DESCRIPTION - Nanocomposite material for use in catalyzing a hydrogen evolution reaction (HER), comprises a nanosheet comprising a metal chalcogenide having a formula MXaY'bZc, and a carbonaceous substrate supporting the nanosheet. The carbonaceous material is selected from graphene and reduced graphene oxide (r-GO). M=transition metal having: (a) an oxidation state ranging from +2 to +4, (b) a body-centered cubic (BCC) crystal structure, a face-centered cubic (FCC) crystal structure, or a hexagonal close packed (HCP) crystal structure, or (c) both an oxidation state ranging from +2 to +4 and BCC, FCC, or HCP crystal structure; or a transition metal selected from tungsten, molybdenum, nickel, cobalt, copper, and iron; X=first chalcogen element; Y'=optional second chalcogen element; Z=optional third chalcogen element; or X and each of Y', and Z, if present, are individually selected from sulfur, selenium, and tellurium; and a-c=0-2. An INDEPENDENT CLAIM is included for catalyzing HER which involves using the nanocomposite material to catalyze a portion of a water electrolysis reaction that produces hydrogen gas with an overpotential of 8-300 mV.