A simple chemical precipitation of ceria based (Sm doped-CGO) nanocomposite: structural and electrolytic behaviour for LT-SOFCs

Doped Ceria Nanomaterials: Preparation, Properties, and Uses

Doping is a powerful strategy for enhancing the performance of ceria (CeO2) nanomaterials in a range of catalytic, photocatalytic, biomedical, and energy applications. The present review summarizes recent developments in the doping of ceria nanomaterials with metal and non-metal dopants for selected applications. The most important metal dopants are grouped into s, p, d, and f block elements, and the relevant synthetic methods, novel properties, and key applications of metal doped ceria are collated and critically discussed. Non-metal dopants are similarly examined and compared with metal dopants using the same performance criteria. The review reveals that non-metal (N, S, P, F, and Cl) doped ceria has mainly been synthesized by calcination and hydrothermal methods, and it has found applications mostly in photocatalysis or as a cathode material for LiS batteries. In contrast, metal doped ceria nanomaterials have been prepared by a wider range of synthetic routes and evaluated for a larger number of applications, including as catalysts or photocatalysts, as antibacterial agents, and in devices such as fuel cells, gas sensors, and colorimetric detectors. Dual/co-doped ceria containing both metals and non-metals are also reviewed, and it is found that co-doping often leads to improved properties compared with single-element doping. The review concludes with a future outlook that identifies unaddressed issues in the synthesis and applications of doped ceria nanomaterials.

Mechanical Properties and Enhancement Mechanism of Oil-Well Cement Stone Reinforced with Carbon Fiber Surfaces Treated by Concentrated Nitric Acid and Sodium Hypochlorite

In this study, carbon fibers (CFs) were used as toughening materials to improve the mechanical properties of cement stone. The surfaces of the CFs were treated with concentrated nitric acid and sodium hypochlorite to increase the interfacial adhesion between the CFs and the cement. The CFs subjected to surface treatment were evaluated by scanning electron microscopy and infrared analysis to find a significant increase in the number of oxygen-containing groups on the surface. The CFs subjected to surface treatment were added to the cement matrix. The effect of the modified CFs on the mechanical properties of the cement matrix was evaluated by testing the means of mechanical properties. The maximum tensile strength, maximum compressive strength, and ultimate strain of the enhanced cement stone of the CFs treated with sodium hypochlorite increased by 68.2%, 12.0%, and 4.4%, respectively. The maximum tensile strength, maximum compressive strength, and ultimate strain of the enhanced cement stone of the CFs treated with concentrated nitric acid increased by 72.7%, 14.7%, and 4.5%, respectively. The addition of CFs to the cement stone exerted no effect on the type of cement hydration products, as determined by infrared analysis and X-ray diffraction. The toughening mechanism of the modified CFs added to the cement stone was ultimately explored, and the bridging effect, deflection effect, and pull-out effect of cracks were evaluated.