双功能三掺杂型碳基非贵金属催化剂的构筑及构效关系研究

Noble metals and metal oxides, such as Pt and IrO2 have been demonstrated as the benchmark catalysts for oxygen electrode reactions. However, the high cost and terrestrial scarcity of these noble metals, along with their limited bifunctional electrocatalytic activity for oxygen reduction reaction (ORR) and oxygen evoluction reaction (OER) on a single electrode, have restricted their large-scale applications. With a view toward addressing these issues, great efforts have been devoted to develop cost-effective bifunctional metal catalysts based on earth-abundant elements. Nowadays, transition metal (M) and N codoped carbon materials (M/N-CMs) are considered to be the most promising bifunctional catalysts. However, the design and synthesis of highly active M/N-CMs towards ORR and OER still remains a significant challenge. Studies have shown that M/N-CMs with different structures and N-containing ligands may exhibit different ORR and OER activity. Furthermore, according to the literature, N and S dual doped carbon materials can show higher electrocatalytic activity towards ORR than solely N-doped carbon materials. In the earlier stage, we have obtained two M/N-CMs with unique nano-assembly structures and one active transition metal、N and S tri-doped carbon materials (M/N/S-CMs). Therefore, in the present study, firstly, we expect to obtain M/N/S-CMs with different polyhedral structures by using three polyhedral carbon as the templates, transition metal salts and suitable ligands containing N and S as the raw materials; next, the morphologies and compositions of the resulting M/N/S-CMs will be characterized by various techniques and their electrocatalytic activity will be evaluated by different methods; finally, the relationship of different polyhedral structures with their ORR and OER activity was demonstrated by the first-principles calculations. The present study aims at evaluation of structure-activity relationship of the synthesized M/N/S-CMs. Moreover, we hope that one or more of the M/N/S-CMs can outperform commercial Pt/C and IrO2/C catalysts in the catalytic activity and long-term operation stability and can be directly applied in fuel cells and metal-air batteries in the future.

氧电极反应多以Pt或IrO2为催化剂，高昂的成本限制了它们的商业化发展。目前，最有发展前景的双功能催化剂是过渡金属（M）和氮共掺杂的碳材料（M/N-CMs）。研究表明，结构和含氮配体均可以影响M/N-CMs的氧还原（ORR）和氧析出（OER）性能；而且，氮和硫双掺杂的碳材料比单独氮掺杂的显示更高的催化活性。前期，我们已经制得两个具有特殊纳米组装结构的双功能催化剂M/N-CMs和一个具有ORR活性的M、氮和硫三掺杂的碳材料（M/N/S-CMs）。本项目拟以三种多面体碳为模板，以过渡金属盐和合适的含氮和硫的配体为原料合成具有不同多面体结构的M/N/S-CMs，并进行相应的表征和电性能测试；最后通过第一性原理计算阐明多面体结构对M/N/S-CMs ORR和OER活性的影响。本研究旨在获得M/N/S-CMs的构效关系，筛选出性能优越的催化剂，以便将来能直接应用到燃料电池和金属-空气电池中。

氧电极和氢电极反应多以Pt/C、RuO2或IrO2为催化剂，高昂的成本和较差的多功能性制约了它们的商业化发展。因此，设计开发全新的多功能非贵金属催化剂成为该领域的研究热点。按照项目计划书的内容，首先，以易得的过渡金属盐、合适的含氮和含硫的配体为原料，制备了系列不同结构和组成的M, N和S三掺杂碳材料（M/N/S-CMs，M = Fe，Co和Ni）催化剂；此外还合成了系列不同结构和组成的M@N掺杂碳（M = Co和Ni）和过渡金属硫化物催化剂。采用多种手段表征了它们的组成、结构和电化学性能，探讨了催化剂组成、结构与性能之间的关系及影响催化剂氧还原、氧析出和氢析出性能的主要因素。最后，我们将筛选出的性能优越的催化剂分别组装成锌空电池和水裂解电池进行了发电性能测试，初步评价了它们的应用前景。完成了预期的研究任务，达到了预期研究目标，得到了一些有意义的成果。目前相关研究成果已发表学术论文9篇，申请国家发明专利4项。