核壳结构Ru@PtRu纳米花电催化剂的制备及碱性氢析出反应性能研究

Core-Shell Structured Ru@PtRu Nanoflower Electrocatalysts toward Alkaline Hydrogen Evolution Reaction

本文通过分步还原Ru、Pt前驱体,制备了以Ru为核、Pt Ru合金为壳的Ru@Pt_(0.24)Ru纳米花电催化剂,其平均直径为16.5±4.0 nm.利用高分辨电子显微镜、电感耦合等离子体原子发射光谱和X射线光电子能谱等表征了这种电催化剂的结构和组成.在1 mol·L^(-1)KOH水溶液中,核壳结构Ru@Pt_(0.24)Ru/C纳米花氢析出反应的过电位为22 mV(@10 m A·cm^(-2)),耐久性测试后过电位增加至30 m V(@10 m A·cm^(-2)),明显优于商业Pt/C电催化剂(初始值:60 m V@10 mA·cm^(-2),耐久性测试后:85 mV@10mA·cm^(-2)).显著提高的电化学活性可能源于核壳结构Ru@Pt_(0.24)Ru纳米花的电子效应和几何效应,耐久性的改善可能源于核壳结构Ru@Pt0.24Ru纳米花结构的稳定性.

Water electrolysis for hydrogen production is beneficial for solving the problem of energy crisis and environmental issues.It is necessary to study highly active and cost-effective catalysts toward hydrogen evolution reaction(HER)to reduce the consumption of noble metals.Herein,we report the synthesis of core-shell structured Ru@Pt_(0.24)Ru nanoflowers electrocatalyst by stepwise reduction of Ru and Pt precursors in the mixture of oleylamine and benzyl alcohol at 160℃.The average diameter of the resultant Ru@Pt_(0.24)Ru was 16.5±4.0 nm with a bulk atomic ratio between Pt and Ru of 0.24:1 and a surface ratio of 3.3:1 between Pt and Ru.Therefore,we speculate the formation of core-shell structure with Ru as the core and Pt Ru alloy as the shell.The performance of the electrocatalyst toward alkaline HER was tested in 1.0 mol·L^(-1)KOH aqueous solution.The Ru@Pt_(0.24)Ru exhibited pronounced alkaline HER activity with a small overpotential of 22 mV at 10 m A·cm^(-2),a low Tafel slope of 43 mV·dec-1,and a high mass activity of 5.68 A·mg-1Pt+Ruat an overpotential of 100 mV,all largely surpassing commercial Pt/C(60 mV,101 mV·dec-1,1.53 A·mg-1Pt).The attained Ru@Pt_(0.24)Ru also held outstanding long-term cycling stability.After 10,000 potential cycles from 0.1 to-0.1 V(vs.RHE),the overpotential increased to 30 mV at 10 m A·cm^(-2),while increased to 85 mV for Pt/C.The significantly improved electrochemical activity may be derived from the electronic and geometric effects of the electrocatalyst.The improvement of durability may be due to the stability of the flower-like dendritic morphology.