Co encapsulated N-doped carbon nanotubes as robust catalyst for valorization of levulinic acid in aqueous media

Abstract

Abstract The construction of an acid resistant catalyst for synthesis of γ-valerolactone from levulinic acid in aqueous media is an important but highly challenging goal. Herein, an efficient Co@NCNT-800 (after 800 °C pyrolysis) catalyst was constructed by confining Co in N-doped carbon nano-tubes (NCNT) from low cost materials by a facile strategy. Combined with the characterization results and control experiments, the in situ formed Co and Co-Ox, but not Co-Nx, proved to be the main synergistic active sites of the catalyst. It was also found that Co species are completely isolated within the bamboo-like NCNT, which could protect the metal nanoparticles from agglomeration and leaching in the strong acid reaction system. The γ-valerolactone yield of no less than 99.9% can be obtained under a relatively mild condition, and the catalytic performance has not been significantly reduced within five cycles. Therefore, this work may pave a way for the design of robust non-noble catalyst, and has potential for the production of γ-valerolactone from biomass in large-scale industries.