摘要
主要研究纳米碳纤维(CNF)的表面改性对析氢反应(HER)催化活性的影响.首先采用一种简单易行的超声处理方法,以混酸(浓硫酸和浓硝酸)为溶剂对CNF进行了表面化学处理,以在其表面引入含氧(CNF-OX)官能团,然后将CNF-OX在氨水中超声处理,以引入含氮(CNF-ON)官能团,以及将CNF-OX和硼酸混合经高温热解对CNF-OX进行掺B处理(B-CNF-OX).XPS结果表明,超声处理可以成功地在CNF表面引入含氧和含氮官能团,硼酸高温处理可以掺入B原子.电化学测试结果表明,经过表面改性后的CNF的HER催化性能都要好于未处理过的CNF-UN,其中N掺杂的CNF-ON表现出最好的HER催化活性,且CNF-OX经掺B处理后,B-CNF-OX的性能也较CNF-OX有所增强,即三者的催化活性大小如下:CNF-OX<B-CNF-OX<CNF-ON.这说明O、B、N杂原子的掺杂会影响纳米碳纤维的析氢催化活性,特别是N原子的掺入对纳米碳纤维HER催化活性有极大的促进作用.
The effects of surface modification of CNF on their electrocatalytic activity for hydrogen evolution reaction （HER） were investigated. Firstly, Oxygen-containing functional groups were introduced onto the CNF surface （labeled as CNF-OX） by a simple sonochemical oxidation in mixed acids （concentrated sulfuric acid and nitric acid） and then the nitro- gen-containing functional groups were introduced onto the CNF-OX surface （labeled as CNF-ON） by sonochemical treat- ment in ammonia, and the B-doped CNF was synthesized by mixing CNF-OX and boric acid in a ratio following by pyrolysis at 800℃ under N2 atmosphere （labeled as B-CNF-OX）. The XPS results showed that the ultrasonic treatments could intro- duce oxygen- and nitrogen-containing functional groups onto the CNF surface successfully, the oxygen atoms content of CNF-OX was increased from 1.96% to 6.01% compared to the untreated CNF （CNF-UN）, and nitrogen atoms content of CNF-ON was increased from 0% to 1.02% compared to CNF-OX. The pyrolysis of boric acid could introduce B element onto the CNF-OX surface where the B atoms content of B-CNF-OX was 1.00%. The linear sweep voltammetry （LSV） test results showed that the HER electrocatalytic activity of the modified CNFs were higher than CNF-UN, and among them CNF-ON had the highest electrocatalytic activities for HER than the others, the onset overpotential of CNF-ON was 344 mV, which shifted 240 mV positively compared to CNF-UN, and the electrocatalytic activity of B-CNF-OX was enhanced by B-doping treatment compared to CNF-OX. The Tafel test indicated CNF-ON had smallest Tafel slop of 154 mV/dec and largest exchange current density of 6.68 p.A/cm^2. The electrochemical impedance spectroscopy （EIS） was carried out to in- vestigate the complex interfacial properties of the CNFs modified electrode, and the results showed that CNF-ON had the smallest charge transfer resistance of 1578 Ω among all the catalysts, which means the nitrogen-doped CNF had higher activ- ity than the oxygen- an
出处
《化学学报》
SCIE
CAS
CSCD
北大核心
2015年第7期729-734,共6页
Acta Chimica Sinica
基金
国家自然科学基金(No.21073061)
上海市大学生创新训练项目(No.S13028)资助~~
关键词
纳米碳纤维
析氢反应
表面改性
电催化性能
电解水
carbon nanofibers
hydrogen evolution reaction
surface modification
electrocatalytic activity
water electroly-sis
