Reactivity of the Alkaline Pretreated Nanoporous Gold for the CO Oxidation

Nanoporous gold (NPG) catalysts were made by free corrosion and the effect of alkali-treatment on NPG has been investigated for the oxidation of CO. After being immersed in alkaline (NaOH or ammonia) solutions, the catalytic activity could be promoted dramatically while used for the room temperature reaction, and this promotional effect could be adjusted by varying the pH values of the alkaline solutions or immersing time. The roles of the alkaline were to provide OH− anions to form Au–OH− sites, which were the active sites to form hydroxyl carbonyl (Au–OCOH−) with CO and activated the oxygen with hydroxyl carbonyl. A probable reaction mechanism was proposed.