杂原子掺杂碳基催化剂与乙炔氢氯化反应的构效关系及失活机理研究

Chlor-alkali chemical industry is one of pillar industries in Xinjiang region, and the investigation of “non-mercy” catalyst for acetylene hydrochlorination is of great significance for the development of chlor-alkali chemical industry in China. At present, the problem of poor stability of Au catalyst has been solved, and Au catalyst presents the potential industrial application to replace Hg catalyst. Therefore, non-metal catalyst with low cost and high catalytic performance may be the developing strategy of “non-mercy” catalyst for acetylene hydrochlorination, due to the expensive cost of Au catalyst. Previous work demonstrates that N-doped carbon exhibits considerable catalytic performance for acetylene hydrochloriantion. However, both the catalytic activity and stability need to be improved. Based on the previous work, we try to elucidate the relationship between the physical structure of N-doped carbon catalyst and its catalytic performance in this project, and then investigate the effect of other heteroatom doping on its turnover frequency, to provide guidance for designing catalyst with excellent catalytic performance. We also try to discuss the deactivation mechanism of the catalyst in the molecule/atom level, using both spectrum and molecular simulations techniques. At last, we will design N-doped carbon catalyst with excellent activity and stability for acetylene hydrochlorination by controlling the physical structure of the catalyst, and provide essential data for the clean production of polyvinyl chloride via calcium carbide method.

氯碱化工是新疆地区工业的支柱产业之一，乙炔氢氯化“无汞”催化剂的研究对国内氯碱化工的发展具有重要意义。目前，金催化剂的寿命问题已获得突破，具有取代汞催化剂获得工业应用的潜力；但鉴于金催化剂昂贵的价格，低成本、高性能的非金属催化剂是乙炔氢氯化“无汞”催化剂未来的发展的方向。前期研究工作表明：氮掺杂纳米碳对乙炔氢氯化反应具有催化作用，但其催化性能远低于金催化剂和汞催化剂。本项目拟在前期工作的基础上，阐明氮掺杂碳基催化剂物相结构与其催化性能的构效关系，探讨杂原子掺杂对催化性能的影响规律，为提高催化活性提供理论指导; 采用光谱手段和分子模拟相结合的方法，从分子/原子水平揭示催化剂表面的失活机理; 通过对催化剂结构的精细调变，设计合成对乙炔氢氯化反应具有高活性、长寿命的氮掺杂碳基催化剂，为电石乙炔法聚氯乙烯的清洁生产提供基础数据。

氯碱化工是新疆地区的支柱产业之一，电石乙炔法制氯乙烯工艺中使用的汞催化剂造成严重的环境污染，乙炔氢氯化“无汞”催化剂的研究对国内氯碱化工的发展具有重要意义。相对于贵金属催化剂，碳催化剂制备成本较低，是“无汞”催化剂近年来的研究热点，但碳催化剂的催化活性和稳定性仍难以满足工业需求。为了提高碳催化剂的催化活性和稳定性， 本项目开展了以下研究：（1）以密度泛函理论和实验表征手段结合，阐明了碳基催化剂失活的本质原因，乙炔在催化剂表面聚合生成的高聚物产生的积碳导致催化剂失活，提出了NH3高温处理可以使失活催化剂有效再生的催化剂再生方法；（2）揭示在了碳基催化剂物相结构与其催化性能的构效关系，发现了碳催化剂中碳缺陷可显著提高催化剂的催化活性、碳催化剂中的sp2/sp3杂化比例最优值在0.45左右、氮硫共掺杂有利于催化剂活性位的调变，铜氮共掺杂对催化剂的稳定性有促进作用等科学规律，为提高碳催化的乙炔氢氯化催化活性和稳定性提供理论指导。（3）在科学规律的基础上，通过对催化剂结构的精细调变，设计制备了高含氮量、高缺陷的氮掺杂碳催化剂，催化剂对乙炔转化率为98％，且可稳定运行500 h，作为乙炔氢氯化非金属催化剂具有巨大的潜在应用价值。项目的研究成果对乙炔氢氯化非金属催化剂的设计和改进具有指导意义，所开发的高性能碳基催化剂进行了反应工艺优化，为电石乙炔法聚氯乙烯的清洁生产提供基础数据。