铂催化剂的几何和表面电子性质对电催化中粒径效应的影响。
The impact of geometric and surface electronic properties of pt-catalysts on the particle size effect in electrocatalysis.
作者信息
Mayrhofer K J J, Blizanac B B, Arenz M, Stamenkovic V R, Ross P N, Markovic N M
机构信息
Materials Science Division, Lawrence Berkeley National Laboratory, University of California, Berkeley, California 94720, USA.
出版信息
J Phys Chem B. 2005 Aug 4;109(30):14433-40. doi: 10.1021/jp051735z.
The particle size effect on the formation of OH adlayer, the CO bulk oxidation, and the oxygen reduction reaction (ORR) have been studied on Pt nanoparticles in perchloric acid electrolyte. From measurements of the CO displacement charge at controlled potential, the corresponding surface charge density versus potential curves yielded the potentials of total zero charge (pztc), which shifts approximately 35 mV negative by decreasing the particle size from 30 nm down to 1 nm. As a consequence, the energy of adsorption of OH is more enhanced, that is, at the same potential the surface coverage with OH increases by decreasing the particle size, which in turn affects the catalytic reactions thereon. The impact of the electronically induced potential shift in the OH adsorption is demonstrated at the CO bulk oxidation, in which adsorbed OH is an educt species and promotes the reaction, and the ORR, where it can act as a surface site blocking species and inhibits the reaction.
研究了在高氯酸电解质中，粒径对铂纳米颗粒上羟基吸附层的形成、一氧化碳体相氧化以及氧还原反应（ORR）的影响。通过在控制电位下测量一氧化碳置换电荷，相应的表面电荷密度与电位曲线得出了零电荷电位（pztc），当粒径从30纳米减小到1纳米时，该电位大约负移35毫伏。因此，羟基的吸附能得到更大增强，也就是说，在相同电位下，随着粒径减小，羟基的表面覆盖率增加，这反过来又影响其上的催化反应。在一氧化碳体相氧化反应中，吸附的羟基是反应物之一并促进反应，在氧还原反应中，它可作为表面位点阻断物种并抑制反应，这证明了羟基吸附中电子诱导电位偏移的影响。
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