A review of self-cleaning photocatalytic surface: Effect of surface characteristics on photocatalytic activity for NO.

Self-cleaning surface has attracted much attention in the field of photocatalytic degradation of NO due to its dirt pickup resistance and self-cleaning effect under the action of rainwater. In this review, the factors affecting NO degradation efficiency were analyzed in terms of photocatalyst characteristics and environmental conditions combined with the photocatalytic degradation mechanism. The feasibility of photocatalytic degradation of NO on superhydrophilic, superhydrophobic and superamphiphobic surfaces was discussed. Furthermore, the effect of special surface characteristics of self-cleaning on photocatalytic NO was highlighted and the improvement of the long-term effect using three self-cleaning surfaces on photocatalytic NO was evaluated and summarized. Finally, the conclusion and outlook were proposed related to the self-cleaning surface for photocatalytic degradation of NO. In future research, the comprehensive effects of the characteristics of photocatalytic materials, self-cleaning characteristics and environmental factors on the photocatalytic degradation of NO and the actual application effects of such self-cleaning photocatalytic surfaces should be further clarified in combination with the engineering. It is believed that this review can provide some theoretical basis and support for the development of self-cleaning surfaces in the field of photocatalytic degradation of NO.

A WO3-TiO2 nanorod/CaCO3 photocatalyst with degradation-regeneration double sites for NO2-inhibited and durable photocatalytic NO.

As a promising cleaner technology for nitric oxide degradation, photocatalysis has attracted extensive attention, while the main limitations of photocatalytic nitric oxide are that the toxic NO2 is produced easily and the photocatalytic durability was inferior due to the accumulation of photocatalytic products. In this paper, a WO3-TiO2 nanorod/CaCO3 (TCC) insulating heterojunction photocatalyst with degradation-regeneration double sites was prepared by simple grinding and calcining. The effects of CaCO3 loading on the morphology, microstructure and composition of TCC photocatalyst were investigated by SEM, TEM, XRD, FT-IR and XPS etc. Also, TCC exhibits NO2-inhibited and durable characteristics for NO degradation. DFT calculation, the detection of active radicals by EPR, capture test and the NO degradation pathway characterized by in-situ FT-IR spectra showed that the electron-rich region formed and the existence of regeneration sites are the main reasons for promoting the NO2-inhibited and durable NO degradation. Furthermore, the mechanism of NO2-inhibited and durable NO degradation by TCC was revealed. Finally, TCC superamphiphobic photocatalytic coating was prepared, which still exhibits similar NO2-inhibited and durable characteristics for NO degradation to TCC photocatalyst. It may provide new application value and development prospects in the field of photocatalytic NO.

Synergetic effect of CQD and oxygen vacancy to TiO2 photocatalyst for boosting visible photocatalytic NO removal.

The wide band gap of TiO2 photocatalyst material limits its application in the field of visible photocatalysis. In this paper, oxygen vacancies and carbon quantum dots (CQD) with up-conversion character were proposed to improve the photocatalytic activity for NO removal of TiO2 under visible light irradiation. The one-dimensional TiO2 nanotube (TNs), TNs containing oxygen vacancies (OVTNs), TNs of composite CQD (CQD-TNs) and OVTNs of composite CQD (CQD-OVTNs) were prepared, respectively. Furthermore, the influence of oxygen vacancies and CQD on the removal of NOx by photocatalysis were explored. It is found that CQD-OVTNs exhibits the conspicuous synergetic effect of CQD and oxygen vacancy to boost visible photocatalytic NO removal, the NO removal efficiency was about 12, 2, and 2.6 times to TNs, OVTNs and CQD-TNs. Also, CQD-OVTNs exhibits the NO2-inhibited property during the process of photocatalytic NO removal. Finally, the synergetic mechanism of CQD and oxygen vacancies to TNs for boosting visible photocatalytic NO removal was revealed.