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

The construction of an acid resistant catalyst for synthesis of gamma-valerolactone from levulinic acid in aqueous media is an important but highly challenging goal. Herein, an efficient Co@NCNT-800 (after 800 degrees 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-O-x, but not Co-N-x, 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 gamma-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 gamma-valerolactone from biomass in large-scale industries. (c) 2020 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by ELSEVIER B.V. and Science Press. All rights reserved.

Automated summary

An efficient acid resistant catalyst for gamma-valerolactone synthesis was successfully constructed, with Co species isolated within NCNT and in situ formed Co and Co-O-x identified as the main synergistic active sites. The catalyst showed high stability and recyclability, achieving a gamma-valerolactone yield of no less than 99.9% under mild conditions. This work may open new pathways for designing robust non-noble catalysts and has potential for large-scale production in industries.