乙二醇稳定的NaBH4还原法制备纳米Pt/C催化剂

Pt/C nanocatalysts prepared by NaBH4 reduction methods using ethylene glycol as a stabilizing agent

分别采用乙二醇(EG)和H2O为溶剂,通过NaBH4还原法在酸性pH≤2和碱性pH≥12条件下制备了铂担载量为20%(质量分数)的Pt/C催化剂,利用TEM、CV及LSV等方法对催化剂进行了表征与测试,考察了EG在NaBH4还原法中对铂纳米颗粒的稳定作用。结果表明,EG作溶剂、碱性pH≥12时,通过NaBH4还原法制备得到了平均粒径约2.5nm、粒径分布窄、在碳载体上分散均匀的Pt/C催化剂;该催化剂的电化学比表面为74.4m2/g Pt,0.8V vs NHE时通过LSV得到的单位质量铂对甲醇电催化氧化的电流密度为229.1mA/mg Pt,分别是相同条件下H2O作溶剂时制备得到的Pt/C催化剂的5.倍和5.3倍。

Pt/C catalysts containing 20wt% platinum per carbon were prepared by NaBH4 reduction methods in acidic ethylene glycol （EG） or H2O conditions of pHi2 and alkaline EG or H2O conditions of pHil2, and characterized by transmission electron microscopy （TEM）, cyclic voltammetry （CV）, and linear sweep voltammetry （LSV）, investigating the stabilizing effect of solvent EG in the NaBH4 reduction method. The results indicate that Pt nanoparticles uniformly distributed on the carbon support with mean diameter of 2.5nm,were prepared by the NaBH4 reduction method in alkaline EG solutions of pH≥12. Electrochemically active specific surface area （ECSA） and Pt-mass based current density of the catalyst for methanol electrooxidation at potential of 0.8V vs NHE from LSV,are 74. 4m^2/g Pt and 229. 1mA/mg Pt,5.6 times larger and 5.3 times higher than those of the catalyst prepared in alkaline H2O solutions of p H≥12,respectively.