Recent Developments in APXPS at the Shanghai Synchrotron Radiation Facility

After 50 years of effort, near-ambient or ambient pressure X-ray photoelectron spectroscopy (NAP-XPS or APXPS) has become a useful tool for studying gas and liquid molecules in environmental science The developments of new-generation synchrotron radiation in recent decades—e.g., more brilliant light, tighter spot size, and well-controlled polarization—have further improved the quality of APXPS studies and enabled their applications in various fields, especially in ca-talysis and material science. Currently, there are more than 20 APXPS endstations built in synchrotron radiation facilities worldwide. In the near future, some APXPS endstations will be upgraded or have been proposed for upgrades, while a few new ones are under construction. This success of APXPS is realized not by the sole improvement of instrumentation, but also through interactions between the desire to explore new scientific phenomena and advanced techniques. Tender X-ray APXPS is a good example of how scientific desire to study the electrochemical liquid-solid interfaces has driven the development of experimental tools.