Cu@PtCu催化薄膜的构筑及氧还原催化性能研究

Construction and Oxygen Reduction Catalytic Performance of Cu@PtCu Catalytic Films

采用喷涂或转印方法制备的质子交换膜燃料电池催化层存在活性不均匀或活性位点易失效的问题。本研究用静电纺丝法制备高导电性的柔性碳纳米纤维薄膜,然后将析氢电位较高的Cu以脉冲电沉积的方式均匀沉积到纤维膜上,制备出Cu纳米晶/碳纳米纤维膜,最后通过原位置换还原,合成Cu@PtCu/碳纳米纤维(Cu@PtCu/CNF)催化薄膜。Cu@PtCu/CNF催化薄膜解决了催化层活性不均的问题,且可以直接作为催化层使用。采用SEM、XRD、XPS等对其形貌、结构进行了表征。电化学测试结果表明,在pH=4、氯铂酸浓度为0.25 mg·mL^(-1)时获得的Cu@PtCu/CNF催化薄膜,其面积比活性为49 m^(2)·g^(-1)。在5 000个循环的稳定性测试后,电化学活性比表面积保持74%,半波电位下降了9 mV,均优于商业Pt/C催化剂。

The catalytic layers of proton exchange membrane fuel cells prepared by spraying or transfer printing methods have problems of uneven activity or easy failure of active sites. In this study, a flexible carbon nanofiber film with high conductivity was prepared by electrospinning, and then Cu with high hydrogen evolution potential was uniformly deposited on the fiber film by pulse electrodeposition to prepare Cu nanocrystal@PtCu/carbon nanofiber film. Finally, a Cu@PtCu/carbon nanofiber(Cu@PtCu/CNF) catalytic film was synthesized by situ exchange reduction. The Cu@PtCu/CNF catalytic film solves the problem of uneven activity of the catalytic layer. It can be directly used as the catalytic layer. Its morphology and structure were characterized by SEM, XRD, XPS. The electrochemical test results show that Cu@PtCu/CNF catalytic films obtained at pH=4 and chloroplatinic acid concentration of 0.25 m·mL-1have an area specific activity of 49 m^(2)·g^(-1). After 5 000 cycles of stability testing, the electrochemically active specific surface area remains 74%, and the half-wave potential decreases by 9 mV, both better than commercial Pt/C catalysts.