Search

Anisotropic and heterogeneous solids, comprising a minimum of two or more elements with different properties, appear pervasively in rock materials including the pore structure and mineral composition of quartz and granite and usually have extensive applications in construction aggregates, dimension stone, geotechnical engineering, and petrology/geology. The elastic stress fields of inhomogeneous materials or composites inevitably change due to the presence of heterogeneous microstructure under applied external conditions, and hence the total mechanical and physical properties are affected by the temperature and pore pressure fluctuations beneath the surface. In this paper, the thermoporoelastic (TPE) approach on the basis of eigenstrain concept is introduced to predict the stress fields in fluid-saturated porous geologic materials like hydrocarbon reservoirs or aquifers by accounting for the coupling between thermal, poroelastic, and mechanical effects. It is an extension of the micromechanical theory that also incorporates thermal effects like pore pressure changes and temperature alternations. In addition, the TPE approach provides an important multiphysical modeling tool for understanding subsurface fluid-rock interactions and stress states in applications like unconventional oil/gas and geothermal energy. [ABSTRACT FROM AUTHOR]

With climate change and environmental issues, the emissions of CO 2 and its greenhouse effect have become a focal point. At present, the utilization of CO 2 includes its synthesis into chemicals and fuels such as methane, methanol, and CO. CO 2 utilization can be achieved through carbon capture and storage technologies, which involve capturing CO 2 from industrial emissions and storing it to reduce the CO 2 concentration in the atmosphere. However, these CO 2 capture and utilization technologies still face challenges, such as technical immaturity and high costs. One of the CO 2 capture and utilization technologies is the production of energy storage materials. In this study, CO 2 captured by molten salt was used as the carbon source, and TiO 2 nanotube arrays were used as precursors. Titanium carbide nanotube arrays(TiC-NTAs)with high specific surface area and high conductivity were prepared by electrolysis. Afterward, the electrochemical energy storage performance of TiC in different electrolytes was tested. The results show that reducing the ionic radius of the electrolyte is conducive to increasing the area-specific capacitance of the device and that the degradation of the cycle life of the quasi-solid supercapacitor may be caused by an increase in the internal resistance due to the loss of water from the electrolyte. This study provides a reference value for the low-temperature synthesis of nanometal carbides and the selection of electrolytes., Competing Interests: The authors declare no competing financial interest., (© 2024 The Authors. Published by American Chemical Society.)

This study aims to investigate the enhanced low temperature denitration activity and promotional mechanism of a cerium-based catalyst through copper modification. In this paper, copper and cerium oxides were supported on TiO 2 -ZrO 2 by an impregnation method, their catalytic activity tests of selective catalytic reduction (SCR) of NO with NH 3 were carried out and their physicochemical properties were characterized. The CuCe/TiO 2 -ZrO 2 catalyst shows obviously enhanced NH 3 -SCR activity at low temperature (<300 °C), which is associated with the well dispersed active ingredients and the synergistic effect between copper and cerium species (Cu 2+ + Ce 3+ ↔ Cu + + Ce 4+ ), and the increased ratios of surface chemisorbed oxygen and Cu + /Cu 2+ lead to the enhanced low-temperature SCR activity. The denitration reaction mechanism over the CuCe/TiO 2 -ZrO 2 catalyst was investigated by in situ DRIFTS and DFT studies. Results illustrate that the NH 3 is inclined to adsorb on the Cu acidic sites (Lewis acid sites), and the NH 2 and NH 2 NO species are the key intermediates in the low-temperature NH 3 -SCR process, which can explain the promotional effect of Cu modification on denitration activity of Ce/TiO 2 -ZrO 2 at the molecular level. Finally, we have reasonably concluded a NH 3 -SCR catalytic cycle involving the Eley-Rideal mechanism and Langmuir-Hinshelwood mechanism, and the former mechanism dominates in the NH 3 -SCR reaction., Competing Interests: There are no conflicts of interest to declare., (This journal is © The Royal Society of Chemistry.)

A series of TiO 2 /ZrO 2 composites with various molar ratios of ZrO 2 :TiO 2 were synthesized by a facile and mild microwave hydrothermal method with carboxymethyl chitosan (CMCS) as templates. The as-obtained products were characterized with wide-angle powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscope (TEM), Fourier transform infrared spectroscopy (FTIR), UV-vis diffuse reflectance spectrophotometry (UV-vis-DRS), N 2 adsorption-desorption isotherms (BET), and X-ray photoelectron spectrometer (XPS). The TiO 2 /ZrO 2 composites with heterogeneous structure consisted of particles which showed a better regularity and uniform with about 800 nm in diameter, and showed a larger specific surface area and smaller energy band gap than pure ZrO 2 . Comparative experiments including varying the pH of the solution and the content of titania demonstrated that the 5% TiO 2 /ZrO 2 composites (n Ti :n Zr  = 5:100) at pH = 10.3 possessed the best photocatalytic property. Moreover, the possible reasons for these phenomena were clarified. Cyclic experiments proved that the resulting TiO 2 /ZrO 2 composites as photocatalyst could be reused efficiently. Meanwhile, a possible mechanism of photocatalysis was proposed., (Copyright © 2019 Elsevier Inc. All rights reserved.)