Figure - available from: Angewandte Chemie International Edition
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TEM and AFM images of PFCNs (a, e), ClCNs (b, f), NOCNs (c, g), and BrCNs (d, h) and their height profiles along the white line (i–l).
Source publication
Herein, small‐sized fluorescent carbon nanoparticles (CNs) with tunable shapes ranging from spheres to various rods with aspect ratios (ARs) of 1.00, 1.51, 1.89, and 2.85 are prepared using a simple anion‐directed strategy for the first time. Based on comprehensive morphological and structural characteristics of CNs, along with theoretical calculat...
Citations
... Recently, carbon dots (CDs), as a rising star of carbon-based nanomaterials, have displayed outstanding merits in terms of dispersion stability, ease of preparation, low cost, and eco-friendliness [21][22][23][24][25]. In general, CDs are defined as small carbon nanoparticles less than 10 nm in size and fluorescence as instinct performance [26][27][28]. ...
Nanomaterials have made significant progress in the field of cementitious materials, but suffer from primary problems of high cost and poor dispersity. Carbon dots (CDs) as a novel low-cost and high-dispersity nano-material preliminarily demonstrate their potential for cement. Nevertheless, it lacks systematic research on their effects on cement properties. For the first time, this work comprehensively investigates the effects of CDs on the hydration, mechanics, and chloride binding of cement composites. More importantly, the relevant mechanisms are revealed in depth. Specifically, cost-efficient ($0.013/g) and well-dispersed (dispersed in simulated concrete pore solution for 7 d) CDs are directly prepared by a facile microwave approach. The CDs dramatically retard the early hydration, improve later mechanical performance, and obviously enhance chloride binding. In detail, 0.2 wt% CDs reduce the second exothermic peak value by 75%, but improve the chloride binding capacity of paste by 51%. And 0.1 wt% CDs enhance the compressive/flexural strength of mortar by 17%/21%. Crucially, related influence mechanisms are uncovered. Namely, CDs create a protective barrier to retard hydration through the complexation of their abundant surface groups with Ca 2+ ; While CDs exert the nucleation effect to boost the formation of C-S-H and Friedel's salt, thereby playing a positive impact on chloride binding; Meanwhile, CDs with suitable dosages carry out nucleation effect to counteract their air-entraining effect, thus improving later mechanical properties of cement composites. This study is expected to provide a novel low-cost and high-dispersity CDs nanomaterial to advance the development of high-performance cementitious materials.
