Zhai Zhouxiao, Chu Jie, Sun Lu, Zhao Xu, Huang Dejin, Yang Xiaoqin, Zhuang Changfu, Min Chungang, Wang Ying
Key Laboratory of Forest Resources Conservation and Utilization in the Southwest Mountains of China Ministry of Education, School of Chemical Engineering, Southwest Forestry University, Kunming 650051, P. R. China.
Research Center for Analysis and Measurement, Kunming University of Science and Technology, Kunming 650093, P. R. China.
ACS Appl Mater Interfaces. 2022 Oct 5;14(39):44439-44449. doi: 10.1021/acsami.2c12874. Epub 2022 Sep 21.
The development of high-content non-noble metal nanocatalysts is important for multiphase catalysis applications. However, it is a challenge to solve the agglomeration in the preparation of high-content metal catalysts. In this paper, a carbon-based catalyst (Co@CN-G-600) with 71.28 wt % cobalt metal content was prepared using a new strategy of gas-phase carbon coating assisted by glycerol. The core of this strategy is to maintain the spacing of metallic cobalt by continuous replenishment of dissociated ligands during pyrolysis over gas-phase glycerol. This approach is also applicable to other non-noble metals. When Co@CN-G-600 was further used as a catalyst for the selective hydrogenation of furfural (FF) to prepare furfuryl alcohol (FOL), the yield of FOL was >99.9% under mild conditions of 80 °C, compared to only 8.23% catalytic yield at up to 130 °C for Co@CN-600 without glycerol. The excellent catalytic performance mainly lies in the fact that the introduction of glycerol modulates the size effect, electronic effect, and acidic site intensity of the high-content Co catalyst, which promotes the activation of FF and hydrogen. Meanwhile, the optimized specific surface area and pore structure by glycerol improve the accessibility of high-density active sites and promote more efficient mass transfer. In addition, the introduction of glycerol produced a graphitic carbon layer encapsulation structure relative to Co@CN-600, which substantially improved the cycling stability of the catalyst. This study resolves the paradox of high content and high dispersion of non-noble metal catalysts in the synthesis process and provides a general pathway and example for the preparation of stable high-content metal catalysts.
高含量非贵金属纳米催化剂的开发对于多相催化应用至关重要。然而，解决高含量金属催化剂制备过程中的团聚问题是一项挑战。本文采用甘油辅助气相碳包覆的新策略制备了钴金属含量为71.28 wt%的碳基催化剂（Co@CN-G-600）。该策略的核心是在气相甘油上热解过程中通过持续补充解离配体来保持金属钴的间距。这种方法也适用于其他非贵金属。当将Co@CN-G-600进一步用作糠醛（FF）选择性加氢制备糠醇（FOL）的催化剂时，在80°C的温和条件下，FOL的产率>99.9%，而对于没有甘油的Co@CN-600，在高达130°C时催化产率仅为8.23%。优异的催化性能主要在于甘油的引入调节了高含量Co催化剂的尺寸效应、电子效应和酸性位点强度，从而促进了FF和氢的活化。同时，甘油优化的比表面积和孔结构提高了高密度活性位点的可及性并促进了更高效的传质。此外，相对于Co@CN-600，甘油的引入产生了石墨碳层包覆结构，这大大提高了催化剂的循环稳定性。本研究解决了非贵金属催化剂在合成过程中高含量与高分散性的矛盾，为制备稳定的高含量金属催化剂提供了一条通用途径和实例。
