High special surface area and “warm light” responsive ZnO: Synthesis mechanism, application and optimization

In this study, a new series of zinc oxide (ZnO) with high specific surface area and narrow energy band gap are prepared using a facile microwave-induced method. The corresponding formation mechanism is also discussed for the first time. Due to the introduction of C, these ZnO can be excited by long wave temperature light without harmful short wave radiation, and play an efficient photocatalytic activity. This valuable property fundamentally improves the biological safety of its photocatalytic application. Herein, taking teeth whitening as an example, the photocatalytic performance of ZnO is evaluated. The “pure” yellow light-emitting diode (PYLED) with high biological safety is used as the excitation source. It is found that this method could effectively remove pigment on the tooth surface through physical adsorption. In addition, these ZnO could generate active oxygen to degrade the pigment on the tooth surface under the irradiation of yellow light. Some further optimization of these “warm light” responsive ZnO is also discussed in this systematical study, which could open up new opportunities in biomedical field. [Display omitted] •A series of ZnO (PZCs, ZnO-BC) with high specific surface area and low band gap were synthesized by simple microwave-induced synthesis.•The introduction of C or BC can effectively reduce the band gap of ZnO.•Long wavelength warm light can effectively stimulate the photocatalytic activity of PZCs and ZnO-BC.•Under the yellow light, ZnO can effectively decompose the pigment on the tooth surface.•Warm light whitening, from the light source and material two levels to reduce the stimulation of teeth, and no obvious damage to enamel.