In-situ fabrication of Bi/BiVO4 heterojunctions with N-doping for efficient elimination of contaminants

In this work, Bi/BiVO4 photocatalysts with N-doping and abundant oxygen vacancies (OVs) were in-situ fabricated via NH3 reduction treatment. One part of the BiVO4 precursor can be reduced to metal Bi? by NH3 reduction treatment, resulting in N-doped BiVO4 with rich OVs. The generation of OVs and metal Bi? has been authenticated by high-resolution transmission electron microscopy (HRTEM) and electron paramagnetic resonance (EPR). The synergistic effect of OVs, N doping and Bi? produces a new photo-generated electron transfer path, which significantly suppresses the reunion of e-/h+ pairs of Bi/BiVO4 heterojunctions with N-doping, substantially improving the competence of BiVO4 to effectively eliminate organic contaminants. The results of photocatalytic destruction experiments evince that the destruction rate of Rhodamine B (RhB) and phenol over 20-BiVO4 is 3 and 4.2 times of that on BiVO4, respectively. Furthermore, photo-stability experiments show that 20-BiVO4 has prominent stability. The segregation and transfer mechanism of photo-induced charge of Bi/BiVO4 heterojunctions with N-doping was elucidated in light of computational study and experimental outcomes. This paper provides a beneficial reference for in-situ construction of high-efficiency photocatalysts.