Photocatalytic NOx abatement and self-cleaning performance of cementitious composites with g-C3N4 nanosheets under visible light

The combination of photocatalyst with cementitious materials for air pollution abatement and self-cleaning has gained considerable attention. However, the most popularly used photocatalytic cementitious composites based on TiO2 achieve the purification function under ultraviolet sunlight, significantly impeding a broader application of photocatalytic cementitious composites. Here, the photocatalytic cementitious composites were prepared by incorporating g-C3N4 nanosheets (CNNs) in Portland cement. With the increase of CNNs content, the photocatalytic NOx abatement and self-cleaning performance was notably improved, while the micro-hardness of cementitious composites increased first and then decreased. Among the three mixing dosages (0.5%, 1% and 2% by weight of cement), the cementitious composite admixed with 2% CNNs showed the highest photocatalytic NOx abatement efficiency of 227.3 mu mol m(-2) h(-1), and could degrade the rhodamine B within 40 min under visible light. Additionally, its microscopic hardness was 5.4% higher than the one without CNNs, suggesting that a moderate amount of CNNs (below 2%) in cementitious composites was effective in achieving an improved photocatalytic depollution performance. (C) 2019 Elsevier Ltd. All rights reserved.