Abstract This study aims to understand the impact of carbonation mechanism of C-S-H and CH in photocatalytic mortars on NOx removal efficiency. Changes in surface chemistry and microstructure induced by the carbonation of portlandite and C-S-H (AFm/AFt) were correlated with the photocatalytic efficiency of the mortars doped with three types of titania-based photocatalysts. Furthermore, the influence of cementitious matrix on the photocatalytic selectivity was evaluated by studying the capacity of hydration/carbonation products to adsorb NO2. The study revealed that in terms of both photocatalytic efficiency and selectivity, mortars with microsilica addition exhibit superior properties over the pure cement-based mortars upon carbonation. Carbonation of C-S-H (AFm/AFt) gel results in the formation of capillary pores between10–50 nm, which outbalances the shielding effects of carbonates formed, leading to the enhanced photocatalytic properties. Moreover, C-S-H gel maintains its high NO2 adsorption capacity even after carbonation, resulting in the high selectivity of the photocatalysis.

中文翻译：

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光催化砂浆降解 NOx：CH 和 CSH 碳化的潜在作用

摘要 本研究旨在了解光催化砂浆中CSH和CH的碳化机制对NOx去除效率的影响。由硅酸盐和 CSH (AFm/AFt) 的碳化引起的表面化学和微观结构的变化与掺杂三种二氧化钛基光催化剂的砂浆的光催化效率相关。此外，通过研究水化/碳酸化产物吸附 NO2 的能力，评估了胶结基质对光催化选择性的影响。研究表明，在光催化效率和选择性方面，添加微硅粉的砂浆在碳化后表现出优于纯水泥基砂浆的性能。CSH (AFm/AFt) 凝胶的碳酸化导致毛细孔在 10-50 nm 之间形成，这抵消了形成的碳酸盐的屏蔽作用，导致光催化性能增强。此外，CSH凝胶即使在碳酸化后仍保持其高NO2吸附能力，从而导致光催化的高选择性。