Fabricating the ternary CeO2@CNTs/CdSe composite with synchronously enhanced adsorption and photocatalytic activity toward water-soluble pollutants removal

Constructing heterogeneous catalyst with different bandgaps is a prospect way to realize efficient charge transfer of catalytic redox reaction. Semiconductor-based catalyst as a prospective material can effectively solve sewage issues under light irradiation, but the efficiency is greatly influenced by the recombination rate of photoelectrons and holes. In this work, cerium dioxide (CeO2) nanoparticles (NPs) were grown in-situ on carbon nanotubes (CNTs), which can maintain the pollutant removal efficiency of pure CeO2 NPs and enhance the adsorption intensity under visible light for CeO2@CNTs composite. Furthermore, the introduction of cadmium selenide (CdSe) was conducive to establish built-in electronic field in the ternary CeO2@CNTs/CdSe catalyst, which effectively enhanced the catalytic activity of CeO2@CNTs/CdSe. In comparison to CNTs, CdSe, CeO2 and CeO2@CNTs composite, the ternary CeO2@CNTs/CdSe catalyst exhibited higher photocurrent intensity, lower recombination of photoelectrons and holes (e-/h+) pairs, indicating much better photocatalytic activity. CeO2@CNTs/CdSe as photocatalyst displayed excellent adsorption ability for Congo red (CR), which contributed to increase the transparency of reaction solution and improve the utilization rate to light, the evaluated degradation efficiency of CR achieved 83.58 % and the reduction ratio of Cr(VI) was nearly 100 %. This work confirms that CeO2@CNTs/CdSe composite with excellent adsorption and photocatalytic ability is a promising photocatalyst material in wastewater treatment.