Abstract:
X-ray absorption spectroscopy (XAS), which includes X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS), is a powerful tool at synchrotron radiation facilities. The XANES region of XAS provides the electronic structure and local geometric information, and the EXAFS region is used to obtain the detailed local atomic structure around the absorbing atoms, such as the nearest neighbor atomic type, the number of atoms in a specific coordination shell, the interatomic distance, and the structural disorder. Generally, one full spectrum which includes EXAFS region needs to spend 15 to 40 minutes collecting. Unfortunately, most chemical reactions happened in a few seconds. Therefore, it is urgent to collect one full spectrum in a few seconds. Here, a quick-scanning X-ray absorption spectroscopy beamline (TPS 44A1) at the Taiwan Photon Source, is presented. The beamline is equipped with a quick-scanning monochromator (Q-mono), which can provide conventional step-by-step scans and on-the-fly scans for a full spectrum1.
Fossil fuels are the most commonly used fuels for energy in our daily lives. However, the concentration of carbon dioxide in the atmosphere has increased year by year due to the excessive use of fossil fuels. In turn, it has caused extreme changes in the global climate. Therefore, finding low-carbon emissions and clean renewable energy is the goal of all countries in the world. Hydrogen is regarded as an ideal alternative clean fuel because it can be effectively converted into energy without producing harmful substances or greenhouse gases. It can be produced by thermally cracking hydrocarbons to produce hydrogen or using photocatalytic or electrocatalytic ways for water splitting. These catalytic reactions are extremely dependent on the activity of metal catalysts. Therefore, it will become an important key to the promotion of hydrogen fuel if the activity of catalysts can be improved and its cost can be reduced. However, it is very important to understand the working pathways of the catalyst. Here, in-situ/operando electrocatalyst characterization2 and methane pyrolysis reactions3 were presented by XAS technique.