Liquid–solid interface of l-cysteine/TM (TM = Ni and Cu) in aqueous solution by means of sulfur K-edge NEXAFS

A liquid–solid interface of l-cysteine on transition metal (TM = Ni and Cu) surfaces has been studied by sulfur K-edge NEXAFS with He path system under atmospheric pressure. l-cysteine becomes a thiolate state under water environment on both TM surfaces and the thiolate bond to the TM surfaces through a metal-thiolate linkage. It is found that since there is no atomic sulfur atom, a S–C bonding does not dissociate. The sulfur atom of l-cysteine has a bonding with three or four water molecules. However, all coordinated water molecules escape from the sulfur surroundings and the S–C bonding dissociates after dry process.