陶瓷电极新型活性界面体系及电解CO2同步电氧化CH4制化学品研究

Conversion of CO2 and CH4 into chemicals is not only a key technology of fossil energy utilization but also a focus for the future clean energy. However, traditional catalytic conversion faces the challenges including harsh operation conditions, low conversion ratios and low selectivity to light olefin. In this proposal, we aim to construct high-performance solid oxide electrolysis cell to simultaneously perform CO2 electrolysis in cathode and CH4 electro-oxidation in anode to produce chemicals. We will develop a radical route to generate chemicals through synergistically tailoring the operation conditions like temperature field and electric field as well as the metal-oxide interface physics and chemistry to shift the catalysis conversion process. We will investigate the growth mechanism of metal-oxide interfaces, and the tailoring mechanism of the interface chemistry and electronic states in in relation to the interface architecture/composition and operation conditions. We will correlate the active species at interface and their influences on the catalysis mechanism of CO2 and CH4 conversion. We also demonstrate the enhancement of coking resistance, sintering resistance and cycling performance with the presence of new interfaces. This approach not only converts CH4 into light olefin but also reduce and utilize CO2 as feed stock, which is an extremely promising route and expected to deliver huge potential.

能源小分子CO2和CH4的转化和利用不但是化石能源高效利用的核心，也是未来清洁能源发展的关键。然而传统催化转化过程面临条件苛刻、转化率低和选择性低等难题。本项目着重于构筑高性能固体氧化物电解池，以CH4和CO2为阳极和阴极反应物，同时构筑新型催化活性界面，通过外场环境如温度场和电场以及界面化学的协同调变从根本上改变催化反应过程，实现电催化转化CH4和CO2制化学品的新途径。研究晶格脱溶策略构筑新型金属-氧化物界面的机制，研究界面结构、界面组分和外场环境对界面化学状态及其相关联界面局域结构的调变机制，明确界面活性物种及其化学状态对CO2电还原和CH4电氧化偶联的催化机制。阐明催化反应新过程对反应物转化率、产物收率及低碳烯烃选择性的增强机制，揭示界面结构及其可逆生长对抗积碳、抗烧结和热循环的性能增强。该程不仅实现CH4向低碳烯烃转化，也实现CO2还原与高值利用，是“一举两得”极具潜力的新途径。

随着世界范围内富含甲烷(CH4)的页岩气大规模工业化开采，以储量相对丰富和价格低廉的天然气替代石油生产液体燃料和基础化学品成为学术界和产业界研究和发展的重点。作为天然气主要成分的CH4分子是自然界中非常稳定的有机小分子，它的选择活化和定向转化是一个世界难题。另一方面，中国已成为世界碳排放第一大国，随着碳交易政策的全面实施，交易额将具备超过万亿的市场规模，对二氧化碳(CO2)进行有效转化与高值利用是实现我国经济快速平稳发展的重要保障。本项目着重于构筑高性能固体氧化物电解器，以CH4和CO2为阳极和阴极反应物，构筑新型催化活性界面，通过外场及界面化学协同调变从根本上改变催化反应过程，实现电催化转化CH4和CO2制化学品的新途径。我们通过构筑金属-氧化物界面精细结构，协同调控外场如电压与温度场，在阴极活化电极构筑氧空位活化裂解CO2制CO，在阳极活化晶格氧裂解CH4制乙烯，实现了电热协同催化CO2和CH4的新过程。发展出晶格脱溶构筑金属-氧化物界面的新策略，明确工况条件下界面化学态的调变规律，揭示CO2电还原和CH4电氧化偶联的催化机制。通过多孔单晶CeO2电极原位脱溶纳米Ni单晶颗粒构筑界面精细结构，采用单晶YSZ电解质构筑电解器实现800oC条件下CO2和CH4高效转化。通过协同调控活性氧物种化学态和通量，实现CH4转化率≥7%、C2产物选择性≥99.5%，高温稳定运行100小时未见显衰减。该程不仅实现CH4向低碳烯烃转化，也实现CO2还原与高值利用，是“一举两得”极具潜力的新途径。