Enhanced carrier separation in g-C3N4/MoO3-x heterostructures towards efficient phenol removal

Abstract

Two-dimensional (2D)/2D g-C3N4/MoO3-x heterojunctions were constructed for enhanced photocatalytic phenol removal. The oxygen vacancies in MoO3-x help to extend absorption in a full solar spectrum especially in near-infrared (NIR) region. Improved charge transfer path preserved photogenerated electrons and holes with powerful enough redox abilities, which simultaneously improved phenol photodegradation performance and photocatalytic activation efficiency of peroxydisulfate (PDS). In full solar spectrum activated PDS system, the phenol removal efficiency using g-C3N4/MoO3-x heterostructures reached 98% within 60 min. For the contribution of PDS activation process, active species trapping experiment and in-situ open-circuit potentials (OCP) measurement indicated that radical and non-radical pathways jointly promoted the elimination of phenol. The existence of oxygen vacancies promoted the formation of catalyst-PDS* complex and thus facilitated the electron transfer process, which exerted crucial effect as non-radical pathway. This result provided an ideal catalyst for photocatalytic persulfate activation system in the field of environmental remediation.