Investigation of Au electrodeposition from [BMP][TFSA] room-temperature ionic liquid containing K[Au(CN)2] by in situ two-dimensional sum frequency generation spectroscopy

► In situ 2D VIS-IR sum frequency generation spectroscopy during Au electrodeposition. ► In situ spectroelectrochemical study of Au electrodeposition from [BMP][TFSA]. ► Potential-dependent co-adsorption of CN− and BMP+ during metal electrodeposition. ► Doubly resonant IR-VIS non-linear response induced by electrochemical adsorption.