Mono-dispersed transition metal nanoparticles on boron-substituted carbon support and applications in hydrogen storage

Abstract

To prepare mono-dispersed transition metal nanoparticles on activated C supports is a long scientific challenge, due to low graphene surface energy. Few polar functional groups in activated C are only located on the plane edges, which are intrinsically difficult to prevent metal clustering, especially at elevated temperatures. This paper discusses a versatile method in preparing stable and uniform transition metal (Pt, Pd, Ti, etc.) nanoparticles (diameter ∼2 nm), using a newly-developed boron-substituted carbon (BC x) support, containing uniform B atoms distributed in the graphene layer structure, which provides a strong specific interaction; this interaction is formed by d-electrons back-donation from transition metals to the empty p-orbital in substituted B atoms. The BC x support shows good adsorption capacity of metal precursors in solutions, and securing the forming metal nanoparticles during thermal reduction at a high temperature (>500 °C). The resulting Pt/BC 12 – with only 0.7 wt.% Pt content – exhibits very high surface activities. At ambient temperature, it offers an impressive hydrogen adsorption capacity at ∼0.5 wt.% per 500 m 2/g surface area, which is more than 5 times higher than the corresponding activated C material with the same surface area.