Researchers Zhang Haimin and Zhao Huijun from the Institute of solid state, Chinese Academy of sciences have prepared zif-67 derived N-doped carbon nanotubes coated Co nanoparticles catalyst

Recently, Zhang Haimin and Zhao Huijun, researchers of Institute of solid physics, Chinese Academy of Sciences, have made important progress in selective hydrogenation catalytic conversion, and constructed a non noble metal catalyst with super high catalytic activity, selectivity and stability, including co-nx active site Relevant research results were published in advanced materials (DOI: 10.1002/adma.201808341) Biomass is one of the most abundant renewable resources on the earth Under the action of suitable catalyst, it can be converted into fuel and chemicals to replace fossil resources Because of its rich oxygen content, selective hydrogenation of biomass derived platform molecules is considered to be one of the most widely used methods in biomass fine chemical production At present, the active components of hydrogenation catalyst mainly depend on precious metals (PT, Au, PD, Ru, etc.), but its low reserves and high price seriously restrict its large-scale application Therefore, the development of low-cost non noble metal high activity hydrogenation catalyst is the key to the realization of biomass applications Due to the poor homogeneity of morphology and size and the single active site, the traditional supported non noble metal nanocatalyst has poor activity, selectivity and stability in the hydrogenation process Recently, the metal nitrogen carbon structure catalyst system based on metal organic framework (MOFs) has been widely concerned by researchers However, the direct carbonization of MOFs at high temperature will lead to the decrease of N content and porosity, which will affect the catalytic performance of the material Therefore, it is necessary to build appropriate nanostructures to maintain the catalytic activity of the materials Due to its unique structure and composition design, the N-doped carbon nanotubes derived from zif-67 have been proved to be an efficient electrocatalyst The researchers attribute their excellent electrocatalytic performance to the synergistic effect of chemical components (appropriate N doping) and multilevel hollow structure However, the catalytic potential of transition metal nanoparticles derived from metal nitrogen carbon materials with this special structure has not been fully explored, especially for the study of traditional thermal catalysis For this reason, the co nanoparticle catalyst coated with N-doped carbon nanotubes derived from zif-67 was prepared by two-step pyrolysis Due to the high temperature step-by-step pyrolysis, the growth of carbon nanotubes is more orderly At the same time, the one-dimensional carbon nanotubes structure can effectively prevent the increase and agglomeration of Co particles in the process of carbonization, so that the Co nanoparticles are highly evenly wrapped on the top of N-doped carbon nanotubes, with an average particle size of 10.4 nm There are a large number of Co-N x active sites in the catalyst, which leads to the super high catalytic activity, selectivity and stability of the non noble metal catalyst Further analysis shows that the catalysts with high activity sites can selectively hydrogenate the biomass based compounds containing aldehyde, ketone, carboxyl and nitro functional groups into corresponding high value-added fine chemicals at room temperature, and their catalytic performance reaches or even exceeds the level of existing noble metal catalysts The related research provides a new and effective way for the preparation of non noble metal based catalysts with high efficiency, and provides an experimental basis for the understanding of new hydrogenation active sites.