Surface microstructure regulation of a novel N-CQDs /C3N4/Bi2WO6 self-cleaning synergistic photocatalytic degradation of NO coating

As well known, the apparent structure and chemical composition of self-cleaning photocatalytic coatings are crucial for their application. In this study, C3N4 with a large specific surface area was introduced into N-CQDs/ Bi2WO6 to construct a highly catalytic active catalyst (CBW-0.5), which continuously degraded 57.7 % of NO. A robust self-cleaning photocatalytic coating (CCBW-B) was prepared by firmly bonding CBW-0.5 to the substrate through a layered spraying process. CBW-0.5 endowed CCBW-B with high catalytic activity, maintaining a degradation rate of 64.9 % for NO, and most of the surface organic dye contamination was degraded after 36 h. Due to the appropriate arrangement of low surface energy substances and micro/nano particles on the surface, CCBW-B with a graded cross network on the surface has contact angles (CA) of 156 degrees/145 degrees for water/olive oil, respectively. The influence of each component of CCBW-B on its photocatalytic and liquid repellent ability was studied, and the patterns for the differences in coating performance due to the changes in surface roughness structure caused by different layer distributions was discussed. In addition, the mechanism for the excellent performance of CCBW-B was explored using SEM, specific surface area, and the theory of the generation and distribution of air pockets. Finally, the durability and self-cleaning ability of CCBW-B were tested, and the synergistic mechanism of self-cleaning and photocatalysis was also provided.