| 摘要:通过奥斯特瓦尔德熟化和乙二醇热还原法合成“蛋黄蛋壳”结构的PtCu催化剂，以及表面改性后的Mn和Cr催化剂。基于电化学活性测试，“蛋黄蛋壳”结构的PtCu催化剂的质量比活性和面积比活性分别为商业Pt/C催化剂的4.8倍和6.4倍。此外，催化剂的耐久性显著优于商业Pt/C催化剂，主要是由于高活性Pt（1 1 1）晶面的暴露。Mn和Cr的表面改性减少了高活性氧还原晶面的暴露，导致氧还原活性略有下降，但有效提高了耐久性。研究还进行了第一原理计算，并分析了氧还原过程中吉布斯自由能的变化，以及催化剂表面原子d带部分态密度。计算结果表明，Mn或Cr表面改性后反应热的绝对值降低，导致阴极氧还原反应（oxygen reduction reaction，ORR）活性降低和耐久性提高，这与实验结果高度一致。 |
| 关键词: 氧还原反应 低铂合金催化剂 奥斯特瓦尔德熟化 表面调控 第一性原理 |
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| “Yolk-Shell” Structure and Surface-Modified Low-Platinum Alloy Catalysts for Oxygen Reduction Performance |
| CHEN Hao,LI Chenwei,WEI Guanghua,ZHANG Junliang |
| Paris Elite Institute of Technology， Shanghai Jiao Tong University， Shanghai 200240， China;School of Mechanical Engineering， Shanghai Jiao Tong University， Shanghai 200240， China |
| Abstract:“Yolk-shell” structured PtCu catalysts，as well as surface modified with Mn and Cr，were synthesized by Ostwald ripening and ethylene glycol thermal reduction methods.Based on the electrochemical activity test，the mass specific activity and area specific activity of the“yolk-shell”structured PtCu are 4.8 times and 6.4 times of commercial Pt/C catalyst respectively.Additionally，the durability of the catalyst is notably superior to commercial Pt/C catalyst，primarily due to the exposure of the highly active Pt（1 1 1）crystal facet.Surface modifications with Mn and Cr decrease the exposure of highly active oxygen reduction facets，resulting in a slight lower oxygen reduction activity but effectively enhanced durability.Furthermore，the first-principle calculation was conducted and the changes in Gibbs free energy during the oxygen reduction process was analyzed，along with the atomic d-band partial density of states on the catalysts surface.The calculation results show reduced absolute value of the reaction heat after surface modification with Mn or Cr，resulting in lower （oxygen reduction reaction，ORR） activity and higher durability，which is in high consistency with the experimental results. |
| Key words: oxygen reduction reaction low-platinum alloy catalyst Ostwald ripening surface modification first-principle method |
