Batista Bruno C, Sitta Elton, Eiswirth Markus, Varela Hamilton
Instituto de Química de São Carlos, Universidade de São Paulo, C.P. 780, CEP 13560-970, São Carlos, SP, Brazil.
Phys Chem Chem Phys. 2008 Nov 28;10(44):6686-92. doi: 10.1039/b811787j. Epub 2008 Sep 30.
We studied the open circuit interaction of methanol and ethanol with oxidized platinum electrodes using in situ infrared spectroscopy. For methanol, it was found that formic acid is the main species formed in the initial region of the transient and that the steep decrease of the open circuit potential coincides with an explosive increase in the CO2 production, which is followed by an increase in the coverage of adsorbed CO. For ethanol, acetaldehyde was the main product detected and only traces of dissolved CO2 and adsorbed CO were found after the steep potential decay. In both cases, the transients were interpreted in terms of (a) the emergence of sub-surface oxygen in the beginning of the transient, where the oxide content is high, and (b) the autocatalytic production of free platinum sites for lower oxide content during the steep decay of the open circuit potential.
我们使用原位红外光谱法研究了甲醇和乙醇与氧化铂电极的开路相互作用。对于甲醇，发现在瞬态初始区域形成的主要物质是甲酸，开路电位的急剧下降与二氧化碳生成的爆发性增加同时发生，随后是吸附态一氧化碳覆盖度的增加。对于乙醇，检测到的主要产物是乙醛，在电位急剧衰减后仅发现痕量溶解的二氧化碳和吸附态一氧化碳。在这两种情况下，瞬态现象可解释为：(a) 在瞬态开始时，由于氧化物含量高，亚表面氧出现；(b) 在开路电位急剧衰减期间，对于较低氧化物含量，自由铂位点的自催化生成。
