Effect of ammonia‐derived species on visible‐light photocatalytic activity of Au supported on amorphous TiO 2 activated by plasma

Amorphous TiO 2 supported Au photocatalyst (Au/AmT) is prepared via modified impregnation method with ammonia washing, followed by cold plasma treatment to activate the photocatalysts. Residual ammonia ([NH 3 ] s ) is formed due to the hydrogen bond between surface OH groups on AmT and ammonia. The [NH 3 ] s suppressed the reduction of Au δ+ and occupied active sites, leading to a poor activity of as‐prepared Au/AmT. The performance of cold plasmas in activation strongly depends on discharge gases. N 2 and O 2 plasmas not only cannot reduce Au δ+ into Au 0 but also convert [NH 3 ] s into poisoning species [NO y ] s during activation. H 2 plasma with a strong reducibility can simultaneously reduce Au δ+ and remove [NH 3 ] s , thus enabling Au/AmT to achieve the highest visible‐light photocatalytic activity in CO oxidation.