Since soil salinization imposes various adverse effects on plants, research on how to relieve salt stress from plants is extremely urgent. We synthesized a new type of cerium-doped carbon quantum dots by a hydrothermal synthesis method. Characterization shows that the carbon quantum dots have a small and uniform particle size, high stability, high water solubility and biocompatibility. Mung bean seeds were soaked in CDs:Ce solutions under a concentration gradient (0.25, 0.5, 1, 2, 3 mg/ mL) and germinated under salt stress (150 mM NaCl). Compared with salt stress, the addition of CDs solutions effectively enhanced the ability of plants to relieve salt stress. The relieving effect on mung bean plants was the most significant after treatment with 2 mg/mL CDs:Ce, and the main root length, plant height and leaf length in comparison with the case of salt stress increased by 83%, 80%, and 60%, respectively. Chlorophyll content, peroxidase activity, superoxide dismutase activity and catalase activity, total protein content increased by 90%, 77%, 76%, 77% and 76%, respectively, malondialdehyde and proline The content decreased by 83% and 77%. Inductively coupled plasma mass spectroscopy proved mung bean plants absorbed CDs:Ce, but the absorption of NaCl decreased by 21.8%. Fluorescence imaging showed CDs:Ce was absorbed by roots, and transferred from the vascular system and apoplastic pathways to stems and leaf veins, and mainly aggregated in intercellular gaps, the vascular system, leaf veins, cilia and stomata. Stereomicroscopy showed that CDs:Ce induction increased the stomatal opening by 15.7%, and improved metabolic efficiency and NaCl excretion from the plants. Hence, CDs:Ce shows great potential in protecting crops from abiotic stress.

Cerium oxide decorated on nickel hydroxide anchored on reduced graphene oxide (Ce-Ni(OH)2/rGO) composite with hexagonal structures were synthesized by facile hydrothermal method. Fourier transform infrared spectroscopy (FT-IR), highresolution transmission electron microscopy with selected area diffraction (HRTEM-SAED), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Brunauer– Emmett–Teller (BET) surface area analysis and electrochemical technology were used to characterize the composite. Due to its unique two-dimensional structures and synergistic effect among Ce2O3, Ni(OH)2 and rGO components indicated twodimensional hexagonal nano Ce-Ni(OH)2/rGO composite is promising electrode material for improved electrochemical H2O2 sensing application. From 50 to 800 μM, the H2O2 concentration was linearly proportional to the oxidation current, with a lower detection of limit of 10.5 μM (S/N = 3). The sensor has a higher sensitivity of 0.625 μA μM−1 cm− 2. In addition, the sensor demonstrated high selectivity, repeatability and stability. These findings proved the viability of the synthetic method and the potential of the composites as a H2O2 sensing option.

This study was aimed at synthesizing and characterizing cerium-doped titania. Cerium-doped anatase titania powders were prepared by sol-gel process, with ammonium (IV) nitrate and titanium (IV) butoxide as the raw materials. The characteristics of pure TiO2 and cerium-doped TiO2 were investigated by XRD, TG/DTA, FE-SEM, and UV-vis spectroscopy. The results of this study show that anatase type of TiO2 was obtained in as-prepared and calcined TiO2 and Ce-TiO2 powder. A DTA curve was also observed as the crystallization temperature decreased with increasing cerium contents. We found that the crystallite size of the obtained anatase particles decreased from 55 nm to 25 nm and the particle size decreased with increasing cerium contents. Moreover, UV-vis spectra showed that anatase titania powders with various cerium contents effectively extend the light absorption properties to the visible region.

The potential application of ultrafine cerium oxide (ceria, ) as an oxygen gas sensor has been investigated. Ceria was synthesized by a thermochemical process: first, a precursor powder was prepared by spray drying cerium-nitrate solution. Heat treatment in air was then performed to evaporate the volatile components in the precursor, thereby forming nanostructured having a size of approximately 20 nm and specific surface area of 100 . After sintering with loosely compacted samples, hydrogen-reduction heat treatment was performed at 773K to increase the degree of non-stoichiometry, x, in . In this manner, the electrical conductivity and oxygen-response ability could be enhanced by increasing the number of oxygen vacancies. After the hydrogen reduction at 773K, was obtained with nearly the same initial crystalline size and surface. The response time measured at room temperature was extremely short at 4 s as compared to 14 s for normally sintered . We believe that this hydrogen-reduced ceria can perform capably as a high-performance oxygen sensor with good response abilities even at room temperature.

Activity of manganese oxide supported on γ-Al2O3 was increased when cerium was added. Also, cerium-added manganese oxide on γ-Al2O3 was more effective in oxidation of toluene than that without cerium. XRD result, it was observed that MnO2+CeO2 crystalline phases were present in the samples. For the used catalyst, a prominent feature has increased by XPS. TPR/TPO profiles of cerium-added manganese oxide on γ-Al2O3 changed significantly increased at a lower temperature. The activity of 18.2 wt% Mn+10.0 wt% Ce/γ-Al2O3 increased at a lower temperature. The cerium added on the manganese catalysts has effects on the oxidation of toluene.