摘要
Exploring high-activity electrocatalyst for oxygen reduction reaction (ORR) is of great significance for a variety of renewable energy conversion and storage technologies. Herein, we fabricated novel ORR electrocatalysts derived from Ni-Co nanoparticles encapsulated in hollow tubular C-N composites (ht-CN) through an easy and scalable pyrolysis route utilizing nickel acetate and cobalt acetate as metal precursors, 2-cyanoguanidine as the nitrogen source, and sucrose as the carbon source. Among the prepared nanocomposite catalysts with different molar ratios ofNi/Co, the catalyst Ni2Co3@ht-CN exhibits an outstanding ORR electroactivity comparable to Pt/C catalyst both in alkaline and neutral media. Home-made zinc-air battery with the Ni2Co3@ht-CN as cathode electrocatalyst presents excellent performance and superior durability either in neutral or alkaline medium. The Ni2Co3@ht-CN battery delivers an open circuit voltage of 1.08 V and a maximum power density of 47 mW cm^-2 in 0.5 mol L^-1 KNO3 solution, while 1.51 V and 314 mW cm^-2 in 6 mol L-^1 KOH solution. In addition, whether in neutral or alkaline solution, the constant current discharge curves of the Ni2Co3@ht-CN battery at different current densities exhibit higher voltage plateau and stability than the Pt/C battery. Results demonstrate the potential application of the catalysts of the present investigation to Zn-air batteries both in alkaline and neutral media.
氧还原反应(ORR)高活性电催化剂的研究对于可再生能源转化和储存技术具有重要意义.我们通过一种简单的热解途径利用乙酸镍和乙酸钴作为金属前体,双氰胺作为氮源,蔗糖作为碳源,将Ni-Co纳米颗粒封装在中空管状C-N复合物(ht-CN)中制备了新型ORR电催化剂.其中, Ni/Co摩尔比为2:3的催化剂Ni2Co3@ht-CN在碱性和中性介质中均表现出与Pt/C接近的优异ORR电活性,以Ni2Co3@ht-CN为阴极的锌-空气电池无论在中性还是碱性中都表现出优异放电性能:在0.5 mol L-1KNO3溶液中的开路电压和最大功率密度分别为1.08 V和47 mW cm-2,而在6 mol L-1KOH溶液中分别为1.51 V和314 mW cm-2;无论是在中性还是碱性溶液中,Ni2Co3@ht-CN电池在不同电流密度下的恒流放电曲线都表现出比Pt/C电池更高的电压平台和稳定性.结果表明本文研究的催化剂是碱性和中性Zn-空气电池优异的阴极材料.
作者
Liang Yu
Qingfeng Yi
Xiaokun Yang
Yao Chen
余亮;易清风;杨孝昆;陈瑶(School of Chemistry and Chemical Engineering, Hunan University of Science and Technology, Xiangtan 411201, China;Hunan Provincial Key Lab of Advanced Materials for New Energy Storage and Conversion, Xiangtan 411201, China;The State Key Laboratory of Pressure Hydrometallurgical Technology of Associated Nonferrous Metal Resources, Kunming 650503, China)
基金
financially supported by the National Natural Science Foundation of China(21875062)
State Key Laboratory of Pressure Hydrometallurgical Technology of Associated Nonferrous Metal Resources(yy20160012),China
