Solar-driven photocatalytic removal of NO over a concrete paving eco-block containing black TiO2

A dispersion containing black TiO(2 )photocatalyst was prepared and sprayed onto the concrete's surface to achieve a black TiO2-based photocatalytic concrete paving eco-block, and its photocatalytic NO removal ratio is approximately 1.7 times as high as that of a white TiO2-based eco-block, resulting from the enhanced optical absorption intensity, abundant oxygen vacancies, and highly produced superoxide anion radicals ((center dot) O-2(-)) of black TiO2. Moreover, the black TiO2-based concrete paving eco-block exhibits significantly enhanced compressive strength and abrasion resistance when using water-glass as a binder, which could satisfy the demand for practical application. Furthermore, in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) was performed to dynamically track the reactive products and intermediates across the surface of the B-TiO2 photocatalyst in a time sequence to investigate the reaction mechanism. It has been demonstrated that almost no harmful by-products were produced when NO was removed via photocatalysis, and the applicability of the as-prepared eco-blocks was evaluated considering the effects of various reaction conditions. Additionally, a computational fluid dynamics (CFD) model for solar-driven photocatalytic abatement of atmospheric NO in a realistic urban street coating with black TiO2-based photocatalytic concrete paving eco-blocks was constructed and simulated to assess the real-world applicability of the developed approach. Overall, this research may offer fresh perspectives on how to create ecologically acceptable photocatalytic products for the removal of air pollutants using solar light.

Automated summary

A dispersion of black TiO2 photocatalyst was prepared and sprayed onto the concrete's surface, resulting in a black TiO2-based photocatalytic concrete paving eco-block with a higher photocatalytic NO removal ratio compared to a white TiO2-based eco-block. The black TiO2-based eco-block also exhibited enhanced compressive strength and abrasion resistance. In situ DRIFTS was used to investigate the reaction mechanism, showing no harmful by-products were produced during the photocatalytic removal of NO. A CFD model was constructed to assess the real-world applicability of the black TiO2-based photocatalytic eco-blocks in urban street coating. Overall, this research offers new perspectives on creating environmentally friendly photocatalytic products for air pollutant removal using solar light.