缺陷富集型钌基电催化剂在强碱和强酸析氢反应中的高质量比活性研究

High mass-specific reactivity of a defect-enriched Ru electrocatalyst for hydrogen evolution in harsh alkaline and acidic media

合理的设计策略以提高贵金属电催化剂在析氢反应(HER)中的利用率,对于简化HER的工艺流程,促进未来能源循环经济的发展至关重要.本文在约2.4 nm的Ru纳米颗粒上设计了大量的缺陷,使其在苛刻的酸性和碱性电解质中具有超高质量比反应活性.在过电势为100 m V时,所制备的缺陷富集型Ru基电催化剂DR-Ru表现出超高的HER翻转频率(碱性:16.4 s^(-1);酸性:20.6 s^(-1))和超低的过电势(碱性:η10=28.2 m V;酸性:η10=25.1 mV),明显优于其他Ru基电催化剂.此外,低配位的Ru活性位和表面部分晶格氧削弱了DR-Ru的Ru–H结合能,促进了酸性HER进行;同时有利于H2O分子分解,缓解了碱性HER过程中水分子的解离迟滞,导致其具有与酸性HER相当的高质量比活性.

A reasonable design strategy to improve the utilization of noble metal electrocatalysts for the hydrogen evolution reaction(HER)is crucial to simplify the process flow and accelerate the future renewable energy economy.Here,abundant defects were created on 2.4-nm Ru nanoparticles to achieve unprecedently high mass-specific reactivity in harsh acidic and alkaline electrolytes.The obtained defect-enriched Ru(DR-Ru)exhibits an ultrahigh HER turnover frequency of16.4 s^(-1)with a 100-mV overpotential in alkaline media,and it also retains an excellent value of 20.6 s^(-1)in acidic media;these results are superior to those reported for other Ru catalysts.Accordingly,a record-low loading of 2.5μg cm^(-2)for the DR-Ru catalysts and low overpotentials of 28.2 and 25.1 mV at10 mA cm^(-2)can be realized in alkaline and acidic media,respectively.Furthermore,the less coordinated Ru surface sites and partial lattice oxygen introduction weaken the bonding between H and DR-Ru catalysts,facilitate fast acidic HERkinetics and help dissociate the water molecule to overcome the major challenge of HER in alkaline electrolytes,leading to an activity comparable to that under acidic conditions.This result provides a guideline for defect engineering on noble metal nanocatalysts to effectively improve the utilization of the catalysts and optimize reactivities.