Exceptional visible-light photoelectrocatalytic activity of dual Z-scheme Bi@BiOI-BiO/CN heterojunction for simultaneous remediation of Cr(VI) and phenol.

Developing highly efficient and stable photocatalysts remains a major challenge for the remediation of environmental pollutants. In this work, the Bi decorated BiOI-BiO/CN heterojunction (Bi@BiOI-BiO/CN) film was fabricated through ultrasonic stripping, I etching and in situ UV-reduction processes and then characterized thoroughly by various analytical techniques. The characteristics of simultaneous mitigation of phenol and Cr(VI) were evaluated over Bi@BiOI-BiO/CN photoanode under visible light. The results exhibited that both phenol and Cr(VI) were removed completely by the photoanode at 2.5 V within 1.5 h, superior to our previous report. The synergy of the surface plasmon resonance (SPR) effect of Bi and ternary heterojunction accelerated the separation and transfer of photo-induced charge carrier and thus heavily promoted the removal efficiency. Moreover, the excellent stability of this photoanode was hold with no considerably activity attenuation after 4 cycles. Finally, a dual Z-scheme charge transfer process was presented. This work offers an attractive pathway to construct highly active photoelectrode with promising application for simultaneous remediation of organics and heavy metals in wastewater.