合成气高选择性制备异丁烷中抗水铜基催化剂的表面结构调变

Conversion of synthesis gas to fuel and chemicals is an important way for the clean and high efficient utilization of coal. The composite catalysts composed of Cu-based methanol synthesis catalyst and β molecular sieve can realize the transformation of synthesis gas to iso-butane with high selectivity. However, the formed by-product water during reaction resulted in the growth of Cu particle, and more water will be produced by the reaction involving CO2 hydrogenation because of the property of CO2-rich synthesis gas obtained from coal. In this project, hydrophilic and hydrophobic property of Cu-based catalyst will be adjusted to solve the above mentioned problem in order to maximize the efficient and stable conversion of synthesis gas to iso-butane. The influence of hydrophilic and hydrophobic property of support on the electronic and chemical environment of Cu active site and the synergistic effect of composite catalyst will be studied systematically. The relation between surface properties and catalytic performance will be revealed. The law of the influence of surface hydrophilic and hydrophobic property of Cu-based catalyst on water molecular diffusion, product distribution and stability will be clearly clarified. All the results will guide us to design and control the surface hydrophilic and hydrophobic properties of Cu-based catalyst, and to eventually provide theoretic basis for the conversion of coal-based synthesis gas to iso-butane with high selectivity and stability.

合成气转化制燃料及化学品是煤炭清洁高效利用的重要途径。采用甲醇合成铜基催化剂与β分子筛组成的复合催化剂可实现合成气高选择性转化制异丁烷，然而反应过程中生成的副产物水极易导致铜基催化剂铜粒子团聚，而且煤基合成气富含CO2，其加氢过程产生更多副产物水，加剧催化剂失活速度。本项目通过对铜基催化剂表面亲疏水性质的调变解决合成气高选择性转化所面临的问题，最大限度地将合成气高效稳定转化制异丁烷。系统研究氧化硅基载体亲疏水性质对铜基催化剂Cu活性位电子环境和化学环境以及复合催化剂协同作用的影响，揭示催化剂表面性质与反应性能的关联规律，明确铜基催化剂表面亲疏水性质对水分子扩散、产物分布以及稳定性的影响规律，通过铜基催化剂表面亲疏水性质的优化设计和微观调控，获得长周期稳定运行的抗水铜基催化剂，为煤基合成气高效稳定转化制异丁烷提供理论基础。

针对合成气一步法制异丁烷反应，研究氧化硅基载体亲疏水性质对铜基催化剂铜活性位电子环境和化学环境以及复合催化剂协同作用的影响，为煤基合成气高效稳定转化制异丁烷提供理论基础。设计了一种简易的旋蒸辅助的沉积沉淀法制备均匀分散的CuZnO/SiO2催化剂，研究了铜基催化剂铜粒径分布对CO2加氢制甲醇反应活性和稳定性的影响。结果表明窄化的铜粒径分布范围可以有效抑制Ostwald熟化效应，提高铜基催化剂稳定性。通过Ce助剂改性，可以动态稳定反应过程中催化剂表面的Cu+和Cu0物种的分布和浓度，抑制铜物种氧化成Cu2+以及铜颗粒团聚长大，提高催化剂稳定性。通过对载体表面亲疏水性质和电子性质调控，合成制备了一系列改性铜基催化剂，探究了铜基催化剂表面亲疏水性质对水分子扩散、产物分布以及稳定性的影响规律。采用甲醇合成铜基催化剂与β分子筛组成的复合催化剂详细研究了合成气制异丁烷反应，探讨H2/COx比、水、CO2/CO比等因素对催化剂活性和稳定性的影响，揭示了催化剂表面性质与反应性能的关联规律。通过铜基催化剂表面性质的优化设计和微观调控，获得了长周期稳定运行的抗水铜基催化剂。