Cobalt Boride Graphene Composites As a Novel Catalyst for Hydrogen Evolution

Abstract

Carbon allotropes like carbon nanotubes and graphene like materials are useful for improving the catalytic ability of transition metals.1 These materials are notable for structural stability and high surface area for the dispersion of catalyst.2 This study explored a novel cobalt catalyst supported on graphene like materials CoB@G for the hydrolysis of sodium borohydride (NaBH4). Sodium borohydride is a hydrogen feedstock material (HFM) that contains 10.8% hydrogen by weight and reacts in water.3 This makes it a choice material for the generation of hydrogen gas; however, this react occurs slowly. CoB@G was synthesized from the reduction of a cobalt metal organic framework (MOF) supported on graphene oxide (CoMOF-5@GO). Hydrolysis of NaBH4 was conducted at temperatures of 283K-303K. Compared to bulk metals: nickel, cobalt, and raney nickel, our catalyst had a great activation energy of 54 kJ mol-1.4 Our product was characterized with Powder X-Ray Diffraction (P-XRD), Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM, Figure 1), Energy Dispersive X-Ray Spectroscopy (EDS), Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES), and Transmission Electron Microscopy (TEM). This product also should good reusability, producing similar amounts of hydrogen after 5 consecutive trials. The hydrolysis of sodium borohydride using our novel catalyst will aid in the mass production of hydrogen for use as an alternative energy source.Works Cited: Huff, C., Dushatinski, T., & Abdel-Fattah, T. M.. Gold nanoparticle/multi-walled carbon nanotube composite as novel catalyst for hydrogen evolution reactions. International Journal of Hydrogen Energy (2017) 42(30), 18985 18990.doi:10.1016/j.ijhydene.2017.05.226Machado, B. F.; Serp, P. Graphene-Based Materials for Catalysis. The Royal Society of Chemistry 2011, 43 (13), 54–75.Schlesingehr H.I.; Brown, H.C.; Finholt A.E.; Gilbreath J.R.; Hoekstra H.R.; Hyde E.L.; Sodium Borohydride, Its Hydolysis and its Use as a Reducing Agent in the Generation of Hydrogen; Chem. Soc., (1953), 75 (1), pp 215–219Kaufman, C. M., & Sen, B. (). Hydrogen generation by hydrolysis of sodium tetrahydroborate: effects of acids and transition metals and their salts. Journal of the Chemical Society, Dalton Transactions, 1985 (2), 307. doi:10.1039/dt9850000307 Figure 1: Graphene supported cobalt borides are shown with SEM imaging. The graphene sheets formed large structures, some of which were over 100 microns in length Figure 1