4.7. Potential and time-dependent in situ Raman spectroscopy
The electrochemical workstation (CHI 660E) and confocal Raman spectrometer (LabRAM HR Evolution) were used to study the in-situ reconstruction phenomenon of catalysts in the HER/OER process. This was mainly divided into two schemes: time-dependent in-situ Raman spectroscopy and potential dependent in-situ Raman spectroscopy. The wavelength and power of the laser source were controlled at 532 nm and 5.36 mW, respectively. The propagation direction of the laser was perpendicular to the working electrode. The acquisition time and accumulation parameters were set to 20 s and double integral mode. In note, unlike traditional electrochemical testing, the catalyst does not need to be activated before in-situ Raman testing, which helps to directly reflect reconstruction process in the initial reaction stage. In addition, all in situ Raman data were collected in stability tests at various application potentials. In situ Electrolytic cell system consists of working electrode (sample), reference electrode (Ag/AgCl), counter electrode (Pt wire), electrolyte solution (1M KOH). Other specific parameters related to specific reaction processes will be discussed in the future, including interval time and application potential.