“…Various photocatalysts have been synthesized and studied, such as TiO 2 [1], ZnO [2], BiVO 4 [3], AgNbO 3 [4], ZnWO 4 [5], etc. ZnO, as a wide direct band gap (3.2 eV) semiconductor, has been attracting much attention in the past decades, and it has been used in different areas, such as solar cell [6], sensor [7,8], magnetic material [9], photoluminescence material [10] and photodegradation [11], etc. ZnO is a good photocatalyst, which presents higher photocatalytic activity than TiO 2 in the photodegradation of some organic compounds [12], so it is a suitable alternative of TiO 2 .…”