大气压冷等离子体-乙醇协同制备钯基甲酸脱氢催化剂及其机理研究

Preparation of supported Pd-based catalysts with high activity and stability for formic acid dehydrogenation is of great significance for accelerating commercialization of direct formic acid fuel cell and the storage and utilization of hydrogen energy. Previous results showed that high performance supported Pd catalysts with smaller size and high dispersion of metallic Pd nanopaticles can be obtained under the influence of the active hydrogen species and the space-limiting effect of ethanol in atmospheric-pressure cold plasma. However, understanding of the preparation mechanism is still in obscure. In this project, atmospheric-pressure cold plasma will be adopted by using the active hydrogen species formed by ethanol, which is easy and safe to store and transport, to prepare Pd-based catalysts for formic acid dehydrogenation by the synergy of atmospheric-pressure cold plasma and ethanol and its mechanism will be disclosed. The structure regulation law and of Pd-based catalysts prepared by atmospheric pressure cold plasma will be established by systematic experimental study, and structure-property relationship of the catalysts will be demonstrated. The preparation mechanism will be disclosed by in-situ optical emission spectroscopy, on-line analytical techniques such as Fourier transform infrared spectroscopy and mass spectroscopy, and other off-line analytical techniques. Based on the understanding of structure regulation law of Pd-based catalysts by cold plasma, structure-property relationship and preparation mechanism, this will provide solid theoretical and experimental foundation for designing and preparation of high-performance Pd-based catalysts for formic acid dehydrogenation.

开发高活性、高稳定性的钯基甲酸脱氢催化剂，对于加速直接甲酸燃料电池商业化进程，以及氢能的存储利用具有重要意义。前期研究表明，采用大气压冷等离子体，以乙醇为氢源，在乙醇产生氢活性物种还原和碳残留物种空间限域效应共同作用下，可制备小粒径、高分散，且具有优异性能的负载型Pd催化剂，但对其制备机制认识较为模糊。本项目拟采用大气压冷等离子体，以安全且易于存储和运输的乙醇为氢活性物种来源，开展大气压冷等离子体-乙醇协同制备钯基甲酸脱氢催化剂及其机理研究工作。通过系统实验研究，建立大气压冷等离子体制备钯基催化剂结构调控规律，并探明催化剂构效关系。通过发射光谱原位诊断研究，傅里叶变换红外光谱和质谱等在线分析技术，以及其他离线分析技术，揭示大气压冷等离子体-乙醇协同制备机理。基于钯基催化剂冷等离子体制备结构调控规律，构效关系及制备机理认识，为高性能钯基甲酸脱氢催化剂的设计和制备提供坚实的理论和实验基础。

开发高性能钯基甲酸脱氢催化剂，对加速直接甲酸燃料电池商业化进程及氢能存储利用具有重要意义。冷等离子体是制备金属催化剂的有效方法，但对其制备机制认识仍较为模糊。本项目主要开展了大气压醇冷等离子体还原金属离子及应用，冷等离子体调控制备Pd/C甲酸脱氢催化剂，冷等离子体调控制备其他金属催化剂及其应用，对相关研究机理和进展进行了探讨和总结，具体如下：.开发了一种安全的大气压醇冷等离子体技术，以安全且易于存储和运输的甲醇和乙醇代替氢气作为氢源，辅助还原金属(Au、Pd、Ag、Pt)离子。发射光谱原位诊断表明，大气压醇冷等离子体产生的基态氢原子，激发态一氧化碳、氢原子和氢分子，是主要还原活性物种。醇分解产生碳物种可调控金等离子共振吸收峰。醇冷等离子体制备Pd/C和Pd/Al2O3的活性与氢冷等离子体制备催化剂活性相当。.采用冷等离子体调控制备Pd/C甲酸脱氢催化剂，探明了工作气体、处理方式、合金化对Pd/C构效关系的影响。冷等离子体处理可促使金属活性组分向载体外表面迁移，实现合金纳米粒子再分散，减小纳米粒子粒径并提高其分散性，增强金属-载体相互作用。氢冷等离子体制备Pd/C分解甲酸活性是氢气热还原制备样品的1.4倍。氢冷等离子体制备PdAu/C-P和氨冷等离子体制备Pd/C-NH3，一次分解甲酸活性是商业Pd/C的1.33和1.13倍，三次活性是8.56和12.60倍。.系统研究了放电电压、时间和工作气氛对冷等离子体调控制备金催化剂构效关系的影响。针对冷等离子体低温特性，将其用于制备不耐热基底载银，并用于杀菌和抗电磁屏蔽。此外，还开展了冷等离子体制备Ru催化剂，并用于等离子体催化协同转化二氧化碳。.对冷等离子体制备金属催化剂反应器、物理化学机理、获得催化剂结构特性、制备面临挑战进行了总结, 并对未来发展进行了展望。上述研究成果，为高性能甲酸脱氢催化剂设计和制备提供了坚实的实验基础和理论依据。