Boron-induced controlled synthesis of Co-nano particles over Bx(CN)y matrix for CO hydrogenation in aqueous media

Abstract

Bx(CN)y supported cobalt nanoparticles have been synthesized by regulating the ratios of melamine and boric acid precursors. The carbonization step is adequate to generate the desired controlled-sized cobalt particles at an auto-reduced state that can eliminate the requirement of promotors (e.g., Pt) for the hydrogen-spillover effect. The presence of nitrogen in support enhances the dispersion of cobalt particles by providing sites for cobalt to nucleate and grow due to the interaction between cobalt and Π electrons from the sp2-N center. Boron in the catalyst system significantly stabilizes the catalyst, thus improving its lifetime. However, the excess of boron promotes the aggregation of cobalt particles; therefore, optimal boron loading is preferable. Moreover, the binding energy calculation of Co6 over the B-doped and undoped C3N4 surface computed through DFT studies shows a reduction in metal-support interaction with the addition of boron, which leads to the aggregation of the cobalt particles with high boron. Overall, the catalyst with the optimized boron and nitrogen-containing support-stabilized cobalt particles is highly efficient in the aqueous phase Fischer-Tropsch synthesis.