Novel dual Z-scheme Bi/BiOI-Bi2O3-C3N4 heterojunctions with synergistic boosted photocatalytic degradation of phenol

Abstract

Photocatalysis is an emerging technique for the remediation of refractory organic contaminants. Herein, a novel dual Z-scheme Bi/BiOI-Bi2O3-C3N4 heterojunctions were constructed through a calcining process following with I− etching and UV-reduction processes. Various analytical technologies were adopted to characterize the materials. As a result, the Bi0 decorated composite presented improved visible-light-response and rapid charge transfer. Due to the synergy of Bi0 and dual Z-scheme heterostructures, a remarkable photocatalytic performance toward phenol degradation was achieved with the highest degradation efficiency of 93.2% and rate constant of 0.0161 min−1 over the optimal composite within 75 min of visible light irradiation. Interestingly, the concentration of the yielded benzoquinone considerably decreased with the introduction of C3N4. Trapping experiments and electron spin resonance (ESR) tests indicated that h+, O2−, OH and e− contributed to phenol remediation, and h+ and O2− were the crucial species toward phenol degradation. Furthermore, outstanding stability was obtained only with a decline of 3.8% after 4 cycles. A reasonable charge transfer mechanism was also proposed. This work provides a new route for in situ construction of Bi0 decorated dual Z-scheme heterojunction for phenolic compounds degradation.