Carbon-Dot-Based Heterojunction for Engineering Band-Edge Position and Photocatalytic Performance

A photocatalytic reaction is always governed by energy band configuration of the catalyst, but its modulation is challenging. Here, the adjustment of band-edge positions of Ag₃ PO₄ through fluorescent carbon dots is reported for the first time. Both Ag₃ PO₄ and carbon dots which keep the similar sizes constitute a heterojunction. Such heterostructure not only promotes visible light absorption, photogenerated charge separation, and transfer, but it also transforms photocatalytic activity of Ag₃ PO₄ from photooxidation to photoreduction due to the huge changes of band-edge positions. In addition, the heterojunction structure of carbon dots and Ag₃ PO₄ exhibits unique temperature-responsive photocatalytic activities and higher photocatalytic stability than the pure Ag₃ PO₄ . According to the contrast experiments and related characterizations, the possible mechanism of photocatalytic reaction is proposed. Therefore, this work offers an alternative route for adjusting energy band positions or tuning photocatalytic performance as well as for preparing novel carbon-dot-based heterostructure.