Formation and characterization of aromatic selenol and thiol monolayers on gold: in-situ IR studies and electrochemical measurements

Adsorption processes and electrochemical properties of benzeneselenol and benzenethiol on gold electrodes were investigated by surface-enhanced IR absorption spectroscopy (SEIRAS) and electrochemical measurements. From the IR spectroscopic measurements, it was confirmed that benzeneselenol molecules adsorbed on the gold surface as benzeneselenolate–Au. SEIRAS measurements revealed that benzeneselenol took a much longer time to adsorb on a gold surface than benzenethiol. Electrochemical reductive desorption of these monolayers in alkaline solution proved that benzeneselenoate chemisorbed on gold surfaces were more stable compared to benzenethiolate, since the reduction peak potential of benzeneselenolate shifted to more than 200 mV negative potential than that of benzenethiolate. The total amounts of adsorbed benzeneselenol molecules were smaller than the case of benzenethiol.