Pt 纳米颗粒在聚二甲基二烯丙基氯化铵功能化碳纳米管上的自发沉积及其对甲醇的电氧化性能

利用聚二甲基二烯丙基氯化铵(PDDA)非共价修饰的碳纳米管(CNTs)与PtCl₆^2-之间的自发氧化还原作用, 制备了Pt 纳米颗粒(Pt NPs)/CNTs-PDDA复合催化剂. PDDA在该催化剂中具有三种作用: (1) 作为金属前驱体PtCl₆^2-还原为Pt NPs 的还原剂; (2) 作为原位产生的Pt NPs 的稳定剂; (3) 在CNTs 表面形成保护膜抑制CNTs 在甲醇电催化氧化过程中的腐蚀. 采用傅里叶变换红外(FTIR)光谱、热重分析和拉曼光谱对CNTs-PDDA进行了表征, 表明PDDA通过π-π作用已成功覆盖在CNTs 表面, 并且修饰过程没有导致CNTs 结构的破坏. 采用透射电子显微镜(TEM)对Pt NPs/CNTs-PDDA 催化剂进行了表征, 结果表明, Pt NPs 均匀地分散在CNTs上, 平均粒径约2 nm, 且粒径分布范围窄. 用循环伏安法、计时电流法进一步考察了Pt NPs/CNTs-PDDA催化剂在酸性介质中对甲醇的电催化氧化的性能. 电化学测试结果表明, 与原始CNTs 负载的Pt NPs催化剂相比,Pt NPs/CNTs-PDDA催化剂具有更高的电化学活性表面积、电催化质量比活性和稳定性.

Spontaneous Deposition of Pt Nanoparticles on Poly(diallyldimethylammonium chloride)/Carbon Nanotube Hybrids and Their Electrocatalytic Oxidation of Methanol

Carbon nanotubes were non-covalently functionalized by poly(diallyldimethylammonium chloride) (PDDA). Here, PDDA has three roles: reductant for the metal precursor of PtCl₆^2-, stabilizer for in-situ produced Pt nanoparticles (Pt NPs), and anti-corrosion film for carbon nanotubes (CNTs). Surface-functionalization of CNTs with PDDA was characterized by Fourier transform infrared (FTIR) spectrometry, thermogravimetric analysis, and Raman spectroscopy. The results indicated that the surface of CNTs was successfully coated with PDDA film by π-π stacking interactions, and the functionalization process had no detrimental effect on the structure of the CNTs. The obtained catalyst (Pt NPs/ CNTs-PDDA) was characterized by transmission electron microscopy, and the results showed that Pt NPs with an average diameter of ca 2 nm were highly dispersed on the surface of CNTs-PDDA. The electrocatalytic properties of Pt NPs/CNTs-PDDA nanohybrids for methanol oxidation were further characterized by cyclic voltammetry and chronoamperometry. Compared with Pt NPs supported on the pristine CNTs, the Pt NPs/CNTs-PDDA catalyst had higher electrochemical surface area and specific mass activity, and better stability towards methanol electro-oxidation.