Fabrication of novel Ag/AgVO3/WO3 homojunction/heterojunction nanomaterials with highly enhanced photocatalytic activity- Investigation on type Ӏ plus Z-scheme mechanism

A series of novel Ag/AgVO3/WO3 homojunction/heterojunction nanomaterials (denoted as AVW-x, x = 10, 20, 30, 40) were designed and synthesized by a simple coprecipitation method. Compared with the other materials, AVW-10 exhibited a unique photochemical performance with a wider absorption range, higher surface area and improved separation of charge carriers. The photocatalytic activity of AVW-10 for degrading RhB was investigated, and the apparent rate constant was 3.11 and 57.2 times higher than those of pure AgVO3 and WO3. Interestingly, the photostability of the recycled catalyst could be significantly enhanced by adding a small amount of benzoquinone (BQ) due to the interaction between BQ and the catalyst, indicating that this addition might be an efficient way to enhance the photoactivity by promoting the separation of photoinduced carriers. Furthermore, trapping experiments were designed and systematically explored, and •O2− was identified as the main active species causing photocatalytic degradation of RhB. A new kind of type Ӏ plus Z-scheme mechanism was also proposed.