AgIO 3-modified AgI/TiO 2 composites for photocatalytic degradation of p-chlorophenol under visible light irradiation

Semiconducting silver iodate (AgIO3) was used to modify the visible light response of an AgI/TiO2 (AIT) catalyst by a facile method. The uncalcined AIT (AITun) and AIT calcined at 200°C (AIT200) consisted of AgIO3, AgI, and TiO2 semiconductors, while that calcined at 450°C (AIT450) was composed of AgI and TiO2. The activity in p-chlorophenol (PCP) degradation under visible light irradiation using either AITun or AIT200 was much higher than that with AIT450, which was mainly attributed to the fact that the presence of AgIO3 provided a new matching band potential. AIT200 exhibited better photocatalytic properties than AITun due to its higher crystallinity after calcination. Moreover, the high catalytic activity of AIT200 was maintained after five successive cyclic experiments under visible irradiation. Considering the effect of radical scavengers and N2 purging on the photocatalysis process, we deduced that the probable pathway of PCP degradation was mainly a surface charge process, caused by valence band holes.