اميرمسعود ياراحمدي

This study investigates the interactions of two-dimensional (2D) materials—specifically graphene quantum dots (GQDs) and molybdenum disulfide (MoS₂)—in a cementitious-like solution. Due to their unique physical and chemical properties, such as high specific surface area, these materials have attracted considerable attention from researchers. The primary objective of this research is to identify the factors influencing thermal conductivity variations in a cementitious matrix upon the addition of semiconductor nanostructures, including carbon-based semiconductors like GQDs and transition metal dichalcogenides like MoS₂. The main challenges addressed in this study involve the synthesis of nanomaterials, achieving their uniform dispersion in the cement-like solution, and enhancing structural bonds under harsh environmental conditions.‌‌Both individual and hybrid samples were prepared to eva‎luate the effects of GQDs and MoS₂, and their mechanical and microstructural properties were characterized using various techniques. Initially, different volumetric concentrations of GQDs (0.5, 1, 2, 4, 6, and 8 mL) were added to the cementitious solution. Based on UV–Vis spectroscopy results, three optimal concentrations were selected. Subsequently, varying weights of MoS₂ (0.0011, 0.0025, and 0.0032 g) were introduced. Twelve composite samples containing different weight ratios of the two nanomaterials were fabricated and analyzed.‌‌ Fourier-transform infrared (FTIR) spectroscopy was employed to assess agglomeration and investigate structural and energetic interactions, while photoluminescence (PL) spectroscopy was used to examine electronic and optical properties. The sample containing 1 mL of GQDs and 0.0025 g of MoS₂ exhibited the highest degree of interaction. Thermal conductivity testing, conducted to assess the materials' heat transfer capabilities, revealed that the GQD– MoS₂ composite reduced the thermal conductivity coefficient to 14 W/m·K at 25°C, representing a 2.3% decrease compared to the reference sample. Furthermore, the hybrid sample demonstrated a 5.4% and 6.6% reduction in thermal conductivity compared to samples containing only GQDs or MoS₂, respectively. These results were corroborated by luminescence analysis, FTIR spectroscopy, and cyclic voltammetry.‌‌Overall, this research highlights the significant potential of 2D materials such as GQDs and MoS₂ in enhancing the properties of cementitious composites.

محلول شبه سيماني , نقاط كوانتومي گرافن , موليبدن دي سولفيد , نانومواد دو بعدي

Cement pore solution , graphene quantum dots , molybdenum disulfide , two-dimensional nanomaterials

amir masoud yarahmadi

Dr. Asghar Habibnejad Korayem