核壳结构Pt-M/REOx/C/Nafion阴极制备及苯电催化加氢还原规律研究

Hydrogenation reduction is an important procedure in diesel refining manufacture process, and Water Electrolysis coupling Organics electro-catalysis Reduction (abbr. WE&OR) technology revealed definitely the available value for use in Hydrogenation reduction reactions. Core-shell structure electrolysis cathodes can be used to enhance adsorb reactant - unsaturated organics, such as Benzene, etc., - in these manufacture processes. But owing to it could not be regulated efficiently on activation of Benzene double bond and behavior of exhaustion hydrogen on the cathode by making use of traditional methods, in the today, regrettably, core-shell structure electrolysis cathodes have been difficult to use actually in WE&OR processes..So, in our project, we will produce core-shell structure Pt-M/REOx/C/Nafion cathodes by employ these technologies, Ion beam Sputtering Enhancing Cosedimentation (abbr. IBSEC), Chemical Modification (abbr. CM) and Depositing Solidifying (abbr. DS). We plan to regulate these technological conditions, such as sputtering voltage, Ion Beam current, oxygen partial pressure and deposition temperature in IBSEC, solution concentration and temperature and modificate time in CM, and dispersant concentration, Nafion / PTFE and pore-forming agent in DS, to control compression strain structure in Pt shell, components and structure in Pt-M/REOx/C/Nafion cathodes, Benzene molecule diffused channel patterns and charge exchange behaviour in cathode - Nafion membrane interface. Then, we will know definitely the regulation mechanism in electric adsorption characteristics of Benzene controlby components and structure of Pt-M/REOx/C/Nafion cathodes surface and electrolysis reaction parameters, and will know definitely the electro-catalysis hydrogenation reduction law of Benzene on cathodes. Finally, we will achieve the aim: enhancing competitive superiority of Benzene hydrogenation relative to cathode hydrogen evolution, increasing hydrogenation selectivity and reduction rate of Benzene on the core-shell structure Pt-M/REOx/C/Nafion cathodes..After complete our research work, we will cognize more fully the relevance between electrode material structure and efficiency of Benzene hydrogenation reduction from these research results. And they can strengthen rationale of applied theory in WE&OR technology, and can supply an effective modulation way and a new research method for Benzene hydrogenation reduction process. In conclusion, our research work has the momentous significance in theory and reality for prospective work of manufacturing catalytic electrode and devising and developing electro-catalysis coupling process.

加氢还原是柴油精制的重要步骤,使用核壳结构电解阴极可以增强对反应物-不饱和有机物(苯等)-的电吸附.由于传统研究方法难以对阴极上苯的双键活化以及氢的析出进行有效调控,因此尚未在水电解-苯加氢还原耦合过程中实用.本项目拟通过离子束溅射增强共沉积、化学修饰与涂覆固化技术制备核壳结构Pt-M/REOx/C/Nafion阴极,通过调控Pt壳压缩应变结构,调节苯分子在阴极-Nafion膜界面扩散通道形态以及二者间电荷交换行为,明确阴极表面结构组分和电解反应参量对苯电吸附性的调控机制,明确苯电催化加氢还原规律,增强苯加氢相对于阴极析氢的竞争优势,提高阴极的苯加氢选择性和还原速度.本项目的实施将有助于认识阴极表面结构与苯加氢还原效率的关系,强化水电解-有机物电催化还原耦合技术的应用理论基础,为苯加氢还原过程提供有效调制途径和新研究方法,对预期的催化电极制备和电催化耦合过程设计开发具有重要理论和现实意义.

加氢还原是柴油精制的重要步骤，使用核壳结构电解阴极可以增强对反应物-不饱和有机物(苯等)-的电吸附。本项目通过离子束溅射增强共沉积、化学修饰与涂覆固化技术制备核壳结构Pt-M/REOx/C/Nafion阴极，通过调控Pt壳压缩应变结构，调节苯分子在阴极-Nafion膜界面扩散通道形态以及二者间电荷交换行为，明确阴极表面结构组分和电解反应参量对苯电吸附性的调控机制，明确苯电催化加氢还原规律，增强苯加氢相对于阴极析氢的竞争优势，提高阴极的苯加氢选择性和还原速度。.（1）表层梯度薄膜的PtCu/CeOx/C催化性能优于其他膜层结构的，表面具有多孔状结构，立体式的增加了表面活性反应位数量；获得表面颗粒是PtCu@Pt核壳结构的Pt-M/REOx/C，壳层压缩应变而存在电子结构效应，i0相比于Pt/C提高近51.32%，ESA值高出约92.32%，Pt载量降低约34.91%。.（2）CeOx可能以非连续的形式附着在Pt的表面，形成Pt-CeOx界面结构；由于SMSI作用，Pt取代进入CeOx形成氧空位，提供准自由电子形成条件，而成为自由电子富集的中心；PtCu/C和PtCu/CeOx/C在Nafion溶液中超声分散，获得4nm左右的PtCu/C/Nafion和PtCu/CeOx/C/Nafion颗粒。.（3）PtCu/CeOx/C/Nafion阴极在苯-水体系中的电化学苯加氢反应，是受扩散控制的不可逆的电化学反应，伴有随后可逆化学反应的特征；PtCu/CeOx/C/Nafion的反应性能与Pt/C/Nafion对比，发现前者析氢电位窗口负移，具有较好的析氢抑制性能，电流效率也远远大于后者；在电解电压为0~-1.2V内，电流效率达到100%，反应由扩散控制为主转化为由电化学控制为主；硫酸浓度是影响苯在阴极过程反应速率的主要因素，氢质子在阴极上的吸附作用强于苯。.本项目获得2项授权发明专利，以第一标注发表及待发表SCI、EI收录期刊论文9篇，参加国际学术会议，发表第一标注会议论文1篇，SCI期刊在审第一标注论文2篇，培养硕士研究生7人。研究成果有助于认识阴极表面结构与苯加氢还原效率的关系，强化水电解-有机物电催化还原耦合技术的应用理论基础，为苯加氢还原过程提供有效调制途径和新研究方法。