Enhancing visible-light-driven NO oxidation through molecular‐level insights of dye-loaded sea sands

Natural minerals,abundant and easily obtained through simple physical processing,offer a cost-effective and environmentally friendly solution for dyeing wastewater disposal and air pollution treatment.This study investigates the photocatalytic removal of NO using natural different types of dyes,loaded on natural sand,under visible light illumination.By examining various coating concentrations of dyes and sand weights,we discovered that sand loaded with Rhodamine B(RhB)exhibits high activity for the photo-oxidation of NO.A combination results of X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS),Fourier transform infrared spectroscopy(FTIR)and thermogravimetric(TG)analyses confirm the presence of SiO_(2),CaCO_(3),Al_(2)O_(3)and iron oxides as the main components of the sand.Furthermore,studying RhB-loaded individual components reveals that CaCO_(3)plays a crucial role in enhancing the NO removal rate.Experimental results and theoretical calculations demonstrate the establishment of a directional charge transfer channel from CaCO_(3)to RhB,facilitating the adsorption and activation of molecular NO and O_(2).This work not only promotes the utilization of natural mineral resources but also enriches the fields of environmental photochemistry and semiconductor photocatalysis.

Enhanced photocatalytic activity and mechanism of CeO_(2) hollow spheres for tetracycline degradation

Recently, researchers have focused on designing and fabricating highly efficient catalysts for photocatalytic organic pollutant removal. Herein, CeO_(2) hollow spheres were prepared through a simple template method followed by calcination at different temperatures for the tetracycline(TC) degradation under simulated solar light illumination. With a calcination temperature ranging from400 to 800 ℃, the as-prepared CeO_(2) hollow structure annealed at 600 ℃(C_(600)) exhibited the best degradation performance with a degradation rate constant of0.066 min-1, which was about six and five times higher than those of the uncalcined sample(C_(0)) and the sample calcined at 800 ℃(C_(800)), respectively. Moreover, sample C_(600)was also superior to the CeO_(2) solid particle photocatalyst. The characterisation results showed that the improved photocatalytic performance was mainly ascribed to the synergistic effect of large specific surface areas, high crystallisation and excellent light scattering ability. Furthermore, the results of active species trapping experiments demonstrated that the superoxide anion(·O_(2)^(-)) radical and hole(h^(+)) played dominant roles in TC degradation. Subsequently, the possible TC degradation pathways and photocatalytic mechanism of CeO_(2) hollow spheres were proposed on the basis of high-performance liquid chromatography–mass spectrometry analysis, main active species and band edge positions of CeO_(2). The results of this study provide a basis for designing and exploring hollow structure catalysts for energy conversion and environmental remediation.