开放结构非贵金属氧化物/石墨烯复合物的电化学可控制备及其氧还原催化性能

The oxygen reduction reaction (ORR) is usually occurred on anode(positive electrode) of both fuel cells and metal-air batteries. Up to date,the main ORR catalyst is Pt-based materials. Disadvantage of hige overpotential , high cost and poor durability has hindered the development of Pt-based catalyst, so the research on non-noble metal catalysts has gained important scientific significance and practical application prospect. Among them, non-precious metal oxide has advantages of low cost, high yield, good stability. However, its electric conductivity is poor and the catalytic activity is greatly affected by its surface structure and morphology. Electrochemical deposition is expected to control facet energy, change different facet relative growth rate and crystal morphology by the specific adsorption of different nolecules or ions. Therefore,this project aims to design and synthesis non-noble metal oxides with open structure (exposing active facet with high surface energy)by electrochemical surface-controlling methods. Using graphene with good conductivity and large specific surface area as a catalyst carrier, we intend to prepare open structural non noble metal oxides/reduced graphene oxide composite materials by exploring various electrochemical methods and study its electrocatalytic performance for oxygen reduction reaction. Moreover, synergistic catalytic effects between non-noble metal oxide crystals and graphene will be investigated and the catalytic mechanism of oxygen reduction on high energy surface will also be studied by Density Functional Theory (DFT). This investigation will provide important scientific basis and experimental foundation for the development of new, green, efficient catalyst for oxygen reduction.

燃料电池和金属-空气电池的阴极（正极）都发生氧还原反应(ORR)。迄今催化ORR以铂基催化剂为主，但其高过电位、高成本和易中毒问题成为制约发展的瓶颈，研究非贵金属催化剂具有重要的科学意义和实际应用前景。其中，非贵金属氧化物成本低、资源丰富、稳定性好，然而它导电性差、催化活性受其表面结构和形态影响大。电化学沉积过程可借助不同分子或离子在晶体表面的特异性吸附调控晶面能的大小，改变不同晶面的相对生长速率，有效地调控晶体形貌。本项目拟以导电性好、比表面积大的功能改性石墨烯为载体材料，通过设计多种途径探索用电化学方法合成开放结构（暴露高表面能活性晶面）的非贵金属氧化物及其与石墨烯的复合物；研究复合物对ORR反应的电催化性能及石墨烯和非贵金属氧化物的协同催化效应；用DFT计算方法研究高表面能活性晶面催化作用机理；为研发新型、高效、低成本的ORR催化剂提供理论及科学实验依据。

本项目重点研究非贵金属氧化物、硫化物及其与石墨烯复合物的绿色合成；研究合成化合物的结构表征及其电催化氧还原性能。此外，还开展了Pt基双功能催化剂和MOFs衍生碳基材料的设计和合成及其电催化性能研究。.通过该项目的系统研究，建立了电化学方法制备特殊形貌非贵金属氧（硫）化物及其与石墨烯的复合物的有效方法；建立并掌握了电化学调控结构和性能的主要方法；通过研究非贵金属氧（硫）化物表面晶相结构与催化氧还原性能之间的构效关系，初步解析了开放结构非贵金属氧（硫）化物具有高催化氧还原活性的可能机理；筛选出了成本低、性能好的新型氧还原催化剂（初始电位和半波电位可分别达到0.95 和0.83 V，极限电流密度可达5.76 mA cm-2），为推进其在燃料电池、金属-空气电池及石油化工领域的实际应用提供了科学理论和实验依据。此外，在设计合成Pt-过渡金属，Pt-光敏性过渡金属氧化物基催化剂及其对MOR和ORR或ORR和HER双功能电光协同催化性能，MOFs衍生碳基材料的设计和合成及其电催化ORR性能等方面都取得可喜进展。.总之，如期完成了项目的研究目标，所取得的理论与实验成果基本上与项目预期拟解决的关键科学问题相一致。 研究成果已发表SCI 学术论文20 篇。其中JCR SCI 一区论文2 篇，二区论文8 篇，三区论文6 篇；授权中国发明专利1件；已接受或投稿待发表论文3 篇。后续研究还在进行中。