Investigation on the stability, electronic, optical, and mechanical properties of novel calcium carbonate hydrates via first‐principles calculations

Abstract

Calcium carbonate (CaCO3) is an inorganic compound which is widely used in industry, chemistry, construction, ocean acidification, and biomineralization due to its rich constituent on earth and excellent performance, in which calcium carbonate hydrates are important systems. In Zou et al's work (Science, 2019, 363, 396‐400), they found a novel calcium carbonate hemihydrate phase, but the structural stability, optical, and mechanical properties have not been studied. In this work, the stability, electronic, optical, and mechanical properties of novel calcium carbonate hydrates were investigated by using the first‐principles calculations using density functional theory. CaCO3·xH2O (x = 1/2, 1 and 6) are determined dynamically stable phases by phonon spectrum, but the Gibbs energy of reaction of CaCO3·1/2H2O is higher than other calcium carbonate hydrates. That is why CaCO3·1/2H2O is hard to synthesize in the experiments. In addition, the optical and mechanical properties of CaCO3·xH2O (x = 1/2, 1 and 6) are expounded in detail. It shows that the CaCO3·1/2H2O has the largest bulk modulus, shear modulus, and Young's modulus with the values 60.51 GPa, 36.56 GPa, and 91.28 GPa. This work will provide guidance for experiments and its applications, such as biomineralization, geology, and industrial processes.

Comparison of CH4 and CO2 Adsorptions onto Calcite(10.4), Aragonite(011)Ca, and Vaterite(010)CO3 Surfaces: An MD and DFT Investigation

“…Likewise, the k -points are automatically set as 4 × 3 × 1, 3 × 3 × 1, and 4 × 4 × 1 for the adsorption systems on the substrates of calcite(10.4), aragonite(011)­Ca, and vaterite(010)­CO 3 respectively. We also noticed that the cutoff energy of 450 eV and k -point grid separation of around 0.03 Å –1 have been successfully implemented in the adsorption system containing the calcite(10.4) surface and calcium carbonate hydrates …”

Numerical optimization for the geometrical configuration of ceramics perform in ZTAP/HCCI wear resistant composites based on actual particle model

“…The ordinate of the stress graph is the stress value on the section line, and the abscissa is the X axis coordinate of the model, as shown in figure 5. In the simplified model, the circular hole coordinates are (12,14), (27,14). In order to make the final calculation results more intuitive, the results were postprocessed and a stress transversal comparison chart was drawn.…”

“…The continuous extension and propagation of cracks may eventually lead to the fracture of the composite material or even the entire layer peeling off 9,10 .HCCI/ZTAP composites materials also have the above problems. Therefore, in order to further improve the performance of HCCI/ZTAP composites, it is important to study and reduce their cracking tendency 11,12 .…”