The comprehensive understanding of contaminant interfacial behavior strongly depends on the in situ characterization technique, which is still a great challenge. In this study, we constructed a device integrated with open-circuit potentialand attenuated total reflectance Fourier transform infrared (OCP-ATR-FTIR) spectroscopy to simultaneously monitor the electrochemical and infrared spectral information on the interfacial reaction for the process analysis, taking the competitive adsorption of hexavalent chromium (Cr(VI)) and oxalate on hematite nanocubes (HNC) as an example. The synchronous OC...