Attapulgite-interpenetrated g-C3N4/Bi2WO6 quantum-dots Z-scheme heterojunction for 2-mercaptobenzothiazole degradation with mechanism insight

The rational utilization of graphitic carbon nitride (g-C3N4) and quantum dots (QDs) semiconductors to highlight their merits as efficient photocatalysts remains attractive and challenging. Targeted integration of g-C3N4 and QDs with expanded interfacial contact and multi-channel electron transfer is an effective means to boost the transfer efficiency of photogenerated electrons and achieve prominent photocatalytic activity. In this article, novel attapulgite (ATP)-interpenetrated Bi2WO6 QDs/g-C3N4 nanocomposites (BWQ/g-C3N4/ATP, designated as BCAs) are successfully fabricated through a simple and effective in situ hydrothermal growth method. The nanorod-structured ATP acts as numerous bridges to intercalate into the interlayers and expands inner space of gC3N4. Theoretical calculation results indicate that an interfacial internal electric field (IEF) is formed where electrons transfer from g-C3N4 to Bi2WO6. Originating from the intact interfacial contact of the expanded g-C3N4 and highly dispersed BWQ with reinforcing electronic transferability of ATP, the optimal sample of BCA5 with higher specific surface area, more active sites and electron transfer channels, and stronger light harvestability, exhibits a nearly-100% degradation of organic contaminant of 2-Mercaptobenzothiazole in water, 35-, 17- and 3fold rate constant higher than that the pristine g-C3N4, BWQ and Bi2WO6/g-C3N4 counterparts, respectively. Various characterization techniques are employed to put forward the mechanisms in depth on MBT degradation route and IEF-induced photocatalytic Z-scheme over the BCA5 under photoexcitation.

Automated summary

The rational utilization and integration of g-C3N4 and QDs semiconductors, as well as expanded interfacial contact and multi-channel electron transfer, have led to the successful fabrication of BCAs nanocomposites with outstanding photocatalytic activity. The optimized sample BCA5 exhibits nearly-100% degradation rate of the targeted organic contaminant.