摘要
Oxygen reduction reaction(ORR)plays a crucial role in many energy storage and conversion devices.Currently,the development of inexpensive and high-performance carbon-based non-precious-metal ORR catalysts in alkaline media still gains a wide attention.In this paper,the mesoporous Fe-N/C catalysts were synthesized through SiO2-mediated templating method using biomass soybeans as the nitrogen and carbon sources.The SiO2 templates create a simultaneous optimization of both the surface functionalities and porous structures of Fe-N/C catalysts.Detailed investigations indicate that the Fe-N/C3 catalyst prepared with the mass ratio of SiO2 to soybean being 3:4 exhibits brilliant electrocatalytic performance,excellent long-term stability and methanol tolerance for the ORR,with the onset potential and the half-wave potential of the ORR being about 0.890 V and 0.783 V(vs RHE),respectively.Meanwhile,the desired 4-electron transfer pathway of the ORR on the catalysts can be observed.It is significantly proposed that the high BET specific surface area and the appropriate pore-size,as well as the high pyridinic-N and total nitrogen loadings may play key roles in enhancing the ORR performance for the Fe-N/C3 catalyst.These results suggest a feasible route based on the economical and sustainable soybean biomass to develop inexpensive and highly efficient non-precious metal electrochemical catalysts for the ORR.
氧还原反应(ORR)在许多储能和能量转换装置中起着至关重要的作用。目前,在碱性介质中开发廉价、高性能的碳基非贵金属ORR催化剂仍受到广泛关注。本文以生物质大豆为氮源和碳源,SiO2为模板剂合成了介孔Fe-N/C催化剂。模板剂SiO2可同时对Fe-N/C催化剂的表面功能和多孔结构进行优化。研究表明,SiO2与大豆质量比为3:4时制备的Fe-N/C3催化剂具有优异的电催化性能、长期稳定性和甲醇耐受性,其ORR的起始电位和半波电位相对于可逆氢电极(RHE)分别约为0.890 V和0.783 V。同时,可以观察到ORR在催化剂表面是四-电子转移路径。结果表明,高BET比表面积和合适的孔径以及较高的吡啶氮和总氮含量对提高Fe-N/C3催化剂的ORR性能具有重要作用。这些结果表明,开发基于经济和可持续的生物质材料大豆的廉价且高效的非贵金属ORR电化学催化剂具有较大的可行性。
作者
WU Qiu-mei
DENG Da-kuan
HE Yi-lun
ZHOU Zhong-cheng
SANG Shang-bin
ZHOU Zhi-hua
伍秋美;邓大款;何轶伦;周忠诚;桑商斌;周智华(State Key Laboratory of Powder Metallurgy,Central South University,Changsha 410083,China;School of Chemistry and Chemical Engineering,Central South University,Changsha 410083,China;School of Chemistry and Chemical Engineering,Hunan University of Science and Technology,Xiangtan 411201,China)
基金
Project(21406273)supported by the National Natural Science Foundation of China
