A stable and active AgxS crystal preparation and its performance as photocatalyst

Abstract

AgxS crystals were synthesized via hydrothermal (AgxS-H) and in situ ion-exchange (AgxS-IE) methods. The samples were characterized by scanning electron microscopy, X-ray diffraction, ultraviolet-visible-near infrared absorption spectroscopy, N2 adsorption-desorption, X-ray photoelectron spectroscopy and surface photovoltage measurements. The photocatalytic performance was investigated for the decomposition of methyl blue (MB) under visible light irradiation (λ ≥ 420 nm). The AgxS-H had smaller particles, wider band gap and weaker recombination of photoinduced charges than AgxS-IE, resulting in a higher photocatalytic activity. Moreover, AgxS-H was stable, and could be reused five times without loss of photocatalytic activity. Additionally, a possible pathway for the photocatalytic degradation of MB over AgxS has been proposed, that MB was oxidized mainly by hydroxyl radicals and partly via electron holes generated in the AgxS. AgxS-H is an efficient photocatalyst and has great potential for the degradation of harmful organic dyes in wastewater.