氮化钛在燃料电池氧还原反应中的研究进展

Research progress of titanium nitride in oxygen reduction reaction for fuel cells

随着世界能源需求总量的持续增长,新型能源的转换利用与存储成为目前科学研究的热点问题。燃料电池作为最具前景的能源转换技术之一,因其能量转化效率高、环境友好、能量密度高、燃料范围广等独特优势受到来自学术界和产业界的广泛关注。氧还原反应(ORR)是燃料电池阴极重要的电极反应,然而其动力学过程缓慢、高度依赖于贵金属铂、长时间运行后催化性能和耐久性急剧退化,现已严重制约燃料电池商业化的大规模推广和应用。因此,研发低成本、高活性和高稳定性的催化剂对推动燃料电池商业化具有重要意义。氮化钛(TiN)材料因具有良好导电性、高熔点、高硬度及耐磨耐酸碱腐蚀等优异特性,在开发高度耐用的催化剂载体领域极具应用前景。具有良好形貌、大比表面积和纳米结构的先进TiN材料作为催化剂载体时,可通过提高贵金属铂利用率、增强金属-载体间相互作用、促进质量/电荷转移以及增强耐腐蚀性,从而实现铂基催化剂电催化活性显著提高。此外,TiN还具有类似贵金属的电子属性,自身对ORR表现出活跃的催化性能和良好的稳定性,在ORR非贵金属催化剂研究中备受青睐。因此,本文综述了具有良好形貌结构特征的TiN材料的制备方法及合成机制,阐述TiN、过渡金属掺杂TiN及其碳基复合材料分别作为催化剂载体或催化剂时在ORR领域的最新研究进展,展望TiN材料在燃料电池阴极中的应用前景,为设计和发展实用型燃料电池阴极催化剂指明方向。

With the increasing consumption of the global energy demand,the electrochemical conversion and storage of new energy sources have drawn increasing attention in scientific research.As a promising energy conversion technology,fuel cells have attracted extensive attention in academia and industry due to their high energy conversion efficiency,environmental friendliness,high power density and wide range of fuels.Especially,oxygen reduction reaction(ORR)at the cathode is considered as an important electrode reaction in fuel cells.However,several factors,including slow kinetic process,extreme dependence on noble metal platinum,and rapid degradation of catalytic performance and durability after long-term operation,have severely restricted the large-scale promotion and application of these fuel cells commercialization.Therefore,the development of low-cost,highly active and stable catalysts is of great significance to promote the commercialization.Recently,Titanium nitride(TiN),as a highly durable support,has attracted extensive attention because of its superior properties of high conductivity,high melting point,high hardness,abrasion resistance and super anti-corrosion to acid and alkaline.When the advanced TiN material with favorable morphology and porous structure,high surface area and nanostructure is used as catalyst support,the electrocatalytic performance of Pt-based catalysts will be enhanced significantly due to the improved utilization of Pt,enhanced metal-support interactions,promoted mass/charge transfer as well as corrosion resistance.Interesting,TiN has also electronic properties similar to noble metal,and exhibits superior catalytic performance and durability toward ORR,thus obtaining widely attention in non-precious metal catalysts.Based on the above analysis,this review has summarized the current preparation method and synthesis mechanism of TiN materials,and elaborated the latest research progress including TiN,transition metal-doped TiN and its carbon-based composite materials as support or catalyst toward ORR.Based on the presented progress,we finally prospect the future application of TiN materials and directions for designing and developing practical fuel cell cathode catalysts.