通过宽背景红外吸收探测金/二氧化钛催化剂金属-载体界面处氢吸附的动力学
Kinetics of H Adsorption at the Metal-Support Interface of Au/TiO Catalysts Probed by Broad Background IR Absorbance.
作者信息
Mahdavi-Shakib Akbar, Kumar K B Sravan, Whittaker Todd N, Xie Tianze, Grabow Lars C, Rioux Robert M, Chandler Bert D
机构信息
Department of Chemistry, Trinity University, San Antonio, TX, 78212-7200, USA.
Department of Chemical and Biomolecular Engineering, University of Houston, Houston, TX, 77204-4004, USA.
出版信息
Angew Chem Int Ed Engl. 2021 Mar 29;60(14):7735-7743. doi: 10.1002/anie.202013359. Epub 2021 Feb 26.
H adsorption on Au catalysts is weak and reversible, making it difficult to quantitatively study. We demonstrate H adsorption on Au/TiO catalysts results in electron transfer to the support, inducing shifts in the FTIR background. This broad background absorbance (BBA) signal is used to quantify H adsorption; adsorption equilibrium constants are comparable to volumetric adsorption measurements. H adsorption kinetics measured with the BBA show a lower E value (23 kJ mol ) for H adsorption than previously reported from proxy H/D exchange (33 kJ mol ). We also identify a previously unreported H-O-H bending vibration associated with proton adsorption on electronically distinct Ti-OH metal-support interface sites, providing new insight into the nature and dynamics of H adsorption at the Au/TiO interface.
氢在金催化剂上的吸附较弱且可逆，难以进行定量研究。我们证明氢在金/二氧化钛催化剂上的吸附会导致电子转移至载体，从而引起傅里叶变换红外光谱（FTIR）背景的位移。这种宽背景吸收（BBA）信号用于量化氢吸附；吸附平衡常数与体积吸附测量结果相当。用BBA测量的氢吸附动力学表明，氢吸附的活化能值（E值）较低（23 kJ·mol⁻¹），低于先前通过氢/氘交换间接测量得到的值（33 kJ·mol⁻¹）。我们还识别出一种先前未报道的与质子吸附在电子性质不同的Ti-OH金属-载体界面位点上相关的H-O-H弯曲振动，这为金/二氧化钛界面处氢吸附的本质和动力学提供了新的见解。
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