Membrane Nanofiber-Supported Cobalt–Nickel Nanoparticles as an Effective and Durable Catalyst for H2 Evolution via Sodium Borohydride Hydrolysis

Abstract

The successful support of bimetallic NiCo alloy nanoparticles (NPs) on poly(vinylidene fluoride-co-hexafluoropropylene) nanofibers (PVDF-HFP NFs) was achieved through electrospinning (ES) and in situ reduction. The synthesis and physicochemical characterization of Ni-Co@PVDF-HFP NFs with a range of bimetallic compositions (Ni1−xCox, x = 0, 0.1, 0.3, 0.5, 0.7, 0.9, and 1) supported on PVDF-HFP NFs was undertaken. In comparison to their counterparts (Ni-PVDF-HFB and Co-PVDF-HFB), the bimetallic hybrid NF membranes demonstrated a significantly increased volume of H2 generation from sodium borohydride (SBH). The high performance of bimetallic catalysts can be attributed mostly to the synergistic impact of Ni and Co. Among all fabricated catalysts, Ni0.3Co0.7@PVDF-HFP produced the highest H2 production in a short time. The maximum generated H2volume was 118 mL in 11.5, 9, 6, and 4.5 min at 298, 308, 318, and 328 K, respectively. Kinetic analyses showed that the hydrolysis process proceeded as a quasi-first-order reaction with respect to the amount of catalyst and as a zero-order reaction with respect to the concentration of SBH. Thermodynamics studies were also undertaken and the parameters were calculated as Ea, ΔS, and ΔH = 30.17 kJ/mol, 0.065 kJ/mol, and 27.57 kJ/mol K, respectively. The introduced NFs can be easily separated and reused, which facilitates their industrialization and commercialization applications in hydrogen storage systems.