揭示Pd-Ag纳米颗粒尺寸对电催化甲醇氧化行为的影响  

Size-dependent methanol oxidation behavior of Pd-Ag synthesized by the high-temperature shock method

作　　者：刘畅 胡峥 李惠 邱意舒 赵文博 周伟 胡适 Chang Liu;Zheng Hu;Hui Li;Yishu Qiu;Wenbo Zhao;Wei Zhou;Shi Hu(Department of Chemistry,School of Science,Tianjin Key Laboratory of Molecular Optoelectronic Science,Tianjin University,Tianjin 300072,China;Institute of Energy,Hefei Comprehensive National Science Center,Hefei 230000,China)

机构地区：[1]Department of Chemistry,School of Science,Tianjin Key Laboratory of Molecular Optoelectronic Science,Tianjin University,Tianjin 300072,China [2]Institute of Energy,Hefei Comprehensive National Science Center,Hefei 230000,China

出　　处：《Science China Materials》2023年第9期3555-3564,共10页中国科学（材料科学（英文版）

基　　金：supported by the National Natural Science Foundation of China (22175127);the Institute of Energy, Hefei Comprehensive National Science Center (19KZS207)。

摘　　要：二元纳米颗粒中元素的分布状态与其电催化性能之间的构效关系对于设计高性能催化剂至关重要.本文通过改变高温冲击法的电流大小,快速制备出一系列具有不同颗粒尺寸和元素分布的Pd-Ag纳米颗粒.研究发现, 30 A冲击电流下得到的Pd-Ag纳米颗粒(PdAg-30A)在电催化甲醇氧化反应中表现出优异的催化性能以及抗CO毒化能力.结合分子动力学与原子芯能级模拟,研究得到了纳米颗粒结构在不同温度下演化的理论图像并据此建立了PdxAg@Ag模型.基于该模型的密度泛函模拟表明, PdAg-30A样品的高性能源于其较低的甲醇分子脱氢势垒和良好的CO+OH共吸附作用.这一研究结果表明了调控二元纳米颗粒中的元素分布在电催化甲醇氧化反应中的重要作用.Exploring the relationship between the elemental distribution and electrochemical performance of nanoparticles,and revealing the involved mechanism is essential to the design of better electrocatalysts.Herein,hightemperature shock(HTS)is used to synthesize Pd-Ag nanoparticles with controllable sizes and mixing degree by applying different currents.Molecular dynamics is performed to simulate the structural evolution in the HTS process and establish the atomic model(PdxAg@Ag)for Pd-Ag nanoparticles,which is difficult to investigate with the conventional characterization methods.The Pd-Ag nanoparticles obtained under an applied current of 30 A exhibit the most outstanding specific activity for the methanol oxidation reaction(MOR)among all samples.By utilizing first-principles and random-walk simulation,the synergy between Pd and Ag is decoupled into the lower barrier of dehydrogenation and higher redox frequency of the Pd-Ag couple.

关 键 词：电催化 密度泛函 共吸附 AG纳米颗粒 甲醇氧化 元素分布 构效关系 冲击电流 

分 类 号：O643.36[理学—物理化学] TM911.4[理学—化学]