Application of Time-Resolved Coherent Anti-Stokes Raman Scattering Technique on the Study of Photocatalytic Hydrogen Production Kinetics

Abstract

Based on the laser pulse output from a femtosecond regenerative amplifier and optical parametric amplifier (OPA), a broadband time-resolved coherent anti-Stokes Raman scattering (CARS) setup was assembled. Using this setup, the relationship of hydrogen CARS spectra to its amount in a mixture with air and the relevant detection time-delay were studied. Hydrogen CARS spectra without nonresonant background interference were obtained by adjusting the detection time-delay. The observed CARS intensity exhibited a linear relationship with the square of hydrogen concentration, which is consistent with the theoretical prediction. The signal-to-noise ratio showed that when the pressure of hydrogen-air mixed gas was 0.1 MPa, the detection limit of our setup was less than 0.2%. Using this setup, the hydrogen production kinetics of a platinum(II) terpyridyl acetylide molecular-cobalt catalysttriethanolamine (TEOA) system was studied. The kinetic mechanism of hydrogen production was discussed by considering the effect of changing pH. The results indicate that a high proton concentration will reduce the hydrogen production efficiency. This can be attributed to the inhibition of hydrolysis of TEOA under acidic conditions, because it is the electron and proton donor in this hydrogen production system. [Article] doi: 10.3866/PKU.WHXB201304281 www.whxb.pku.edu.cn 物理化学学报(Wuli Huaxue Xuebao) Acta Phys. -Chim. Sin. 2013, 29 (8), 1632-1638 August Received: January 31, 2013; Revised: April 28, 2013; Published on Web: April 28, 2013. ∗Corresponding author. Email: lmfu@chem.ruc.edu.cn; Tel: +86-10-62516604. The project was supported by the National Key Basic Research Program of China (973) (2009CB220008). 国家重点基础研究发展规划项目(973) (2009CB220008)资助 C Editorial office of Acta Physico-Chimica Sinica 1632 吕永钢等:利用时间分辨相干反斯托克斯拉曼散射技术研究光催化产氢反应动力学 No.8