Departamento de Química, Universidade Federal de Alagoas-Campus Arapiraca, Bom Sucesso, Arapiraca (AL), Brazil.
Phys Chem Chem Phys. 2011 Jul 14;13(26):12163-72. doi: 10.1039/c1cp20546c. Epub 2011 Jun 3.
Ethanol oxidation on platinum stepped surfaces vicinal to the (111) pole modified by tin has been studied to determine the role of this adatom in the oxidation mechanism. Tin has been slowly deposited so that the initial stages of the deposition take place on the step, and deposition on the terrace only occurs when the step has been completely decorated. Voltammetric and chronoamperometric experiments demonstrate that tin on the step catalyzes the oxidation. The maximum enhancement is found when the step is completely decorated by tin. FTIR experiments using normal and isotopically labeled ethanol have been used to elucidate the effect of the tin adatoms in the mechanism. The obtained results indicate that the role of tin is double: (i) when the surface has sites capable of breaking the C-C bond of the molecule, that is, when the step sites are not completely covered by tin, it promotes the oxidation of CO formed from the molecular fragments to CO(2) through a bifunctional mechanism and (ii) it catalyzes the oxidation of ethanol to acetic acid.
已研究了锡修饰的（111）极斜面上铂阶跃表面的乙醇氧化，以确定该原子在氧化机制中的作用。锡被缓慢沉积，使得沉积的初始阶段发生在台阶上，并且仅当台阶完全被装饰时才在平台上沉积。伏安法和计时安培法实验表明，台阶上的锡催化了氧化。当台阶完全被锡装饰时，发现最大增强。使用正常和同位素标记的乙醇的 FTIR 实验已用于阐明锡原子在机制中的作用。获得的结果表明，锡的作用是双重的：（i）当表面具有能够断裂分子的 C-C 键的位点时，即当台阶位点未被锡完全覆盖时，它通过双功能机制促进从分子片段形成的 CO 氧化为 CO2，（ii）它催化乙醇氧化为乙酸。
