摘要
结合步进扫描傅立叶变换红外光谱仪和红外显微镜,建立了电化学原位步进扫描时间分辨显微镜FTIR反射光谱.采用微电极和利用纳米结构表面的异常红外效应,显著提高表面吸附物种的红外检测灵敏度和红外电极表面对极化电位的响应速度,使广泛应用的外反射型薄层红外电解池的时间常数(τ=R1Cd)从使用常规盘电极的约40ms降低到0.65ms.研究了酸性介质中CO在Pt电极上的吸附过程,谱图的时间分辨率达50μs.
Electrochemical in situ step-scan time-resolved microscope FTIR spectroscopy( in situ SS-TR-MFTIRS) was successively established, for the first time in the present work, by using a step-scan FTIR instrument (Nexus 870 FTIR spectrometer) and an IR microscope (IR-plane advantage microscope). A homemade signal synchronizer was used to generate polarization potential that is in accordance with the signal-time-sequence of step-scan time-resolved spectral data collection. Due to the use of a nanostructured microelectrode of Pt and the enhancement of IR absorption, a character of abnormal infrared effects of the nanostructured Pt surface, IR determination sensitivity of surface species was significantly increased, and the rate of responding to a polarizing potential of electrode surface in a thin-layer IR cell was remarkably improved. Adsorption of CO on nanostructured Pt microelectrode (Phi = 0.2 mm) in sulfuric acid solutions was investigated by using the present new technique, and a spectral time-resolution as fast as 50 mus has been achieved. From the variation versus t of the band center of linear-bonded CO(see Fig. 7) that is measured from in situ SS-TR-MFTIR spectra, the cell constant (T = R1Cd) of an electrochemical thin-layer IR cell of external reflection mode, which is employed widely in studies of electrochemical in situ IR spectroscopy, has been determined to be 0.65 ms. In comparison with the T of 40 ms for a conventional Pt disk electrode (alpha = 6.0 mm), the use of a Pt microelectrode has reduced dramatically the thin-layer IR cell constant to about 61 times. The results obtained in the current paper is of importance in illustrating the success of establishing the in situ SS-TR-MFTIRS, and demonstrating the powerful capability of the in situ SS-TR-MFTIRS for studies of fast dynamic processes of electrode and kinetics of reactions taking place at solid/liquid interfaces as well.
出处
《物理化学学报》
SCIE
CAS
CSCD
北大核心
2002年第11期989-993,共5页
Acta Physico-Chimica Sinica
基金
教育部科学研究基金(29833060
20021002)
国家自然科学基金(20023001)
