Construction of photothermal hybrid with surface-polarized carbon nanotube twined oxygen-vacancy engineered cuprous oxide for improved PMS activation and water purification

Abstract

Photothermal hybrids composed of nanocarbon and metal species are promising in solar-driven photothermal conversion and later application of water purification. Herein, the photothermal hybrid with surface-polarized carbon nanotube (CNT) twined oxygen vacancy-engineered cuprous oxides was constructed. The surface polar oxygen and nitrogen moieties were introduced onto the CNT, enriching the surface polarity of the nanocarbon, which further twined the in-situ generated oxygen vacancy-engineered cuprous oxides. The constructed catalyst was endowed with abundant Cu(I) reactive sites and oxygen vacancy, providing the efficient trapping effect and enough exposed active sites to trigger improved peroxymonosulfate (PMS) activation. In addition, the obtained catalyst affords superior photothermal conversion efficiency, thereby showcasing the great potential in solar-driven water purification. Therefore, the catalyst shows excellent bisphenol A (BPA) degradation performance with a reaction rate constant of 0.47 min^-1, and activation energy (Ea=9.38 kJ·mol^-1).. The reaction mechanism study indicates the main contribution of singlet oxygen and superoxide radicals in the BPA degradation. More importantly, the obtained catalyst affords the excellent total organic carbon (TOC) removal ability for mixed contaminants, higher than that of single contaminant removal, which shows great potential for practical complicated wastewater purification. Finally, the obtained photothermal hybrids were anchored onto the tailored sponge through a hydrogel tethering strategy, which acts as a monolith evaporator to enable cleanwater regeneration and contaminant degradation.