Effects Of CeO2 Nanoparticles Research Articles

Experimental study on the cerium oxide nanoparticles doped in diesel fuel improving the cold start performance of diesel engines at high-altitude and low-temperature environments

CeO2 nanoparticles are effective fuel additives that enhance fuel spray, atomization, and combustion characteristics due to their high catalytic activity and excellent thermal properties. When added to fuel, CeO2 nanoparticles significantly improve in-cylinder combustion, and engine performance, and reduce pollutant emissions under normal engine operating conditions. Diesel engines encounter persistent challenges during cold starts at low temperatures and high altitudes. However, there is limited research on the effects of CeO2 nanoparticles on ignition and combustion at low temperatures and cold start performance. This study aims to evaluate the impact of CeO2 nanoparticles doping in diesel fuel on the cold start performance of diesel engines in high-altitude and low-temperature environments. Diesel fuel doped with CeO2 nanoparticles at various concentrations was prepared using magnetic stirring and ultrasonication. The cold start performance of the test engine was assessed in an environmental chamber. This work investigated and evaluated the improvements of CeO2 nanoparticles on cold start performance from three perspectives: general low-temperature conditions, high-altitude environments, and extreme low-temperature scenarios with diethyl ether premixing. Experimental results indicate that incorporating CeO2 nanoparticles expanded the critical temperature required for a successful cold start from 0 °C to −5 °C. At high altitudes, the addition of CeO2 nanoparticles effectively increased the proportion of efficient combustion, evidenced by single peak and parent peak patterns during cold starts. CeO2 nanoparticles facilitated the transition from low-temperature to high-temperature reactions, promoting fuel ignition during the first injection cycle and reducing speed fluctuations during cold starts with diethyl ether premixing at −40 °C. Furthermore, adding CeO2 nanoparticles prevented detonation and rapid pressure surges during cold starts. Overall, doping diesel fuel with CeO2 nanoparticles proves to be an effective method for enhancing cold start performance in diesel engines. This study offers a novel approach for improving diesel engine cold start performance in high-altitude and low-temperature conditions.

Effect of CeO2 nanoparticles on hydroxyl radicals in EPR studies of the photodegradation of methylene blue under influence of red light

The antioxidant properties of cerium dioxide nanoparticles synthesized by the hydrothermal method are studied both by optical photometry and by EPR spectroscopy. It was found that with increasing intensity of irradiation of methylene blue with red light, the antioxidant activity of CeO2 nanoparticles improve. The greatest antioxidant activity is achieved at a concentration of CeO2 particles in solution from 5 mM to 10 mM. Increasing a concentration of CeO2 nanoparticles above 20 mM leads to deterioration in their antioxidant properties. It has been shown that in an alkaline medium the antioxidant activity of nanoparticles increases significantly, but with a decrease in pH to 3, CeO2 nanoparticles exhibit weak pro-oxidant properties due to more active generation of O2− radicals.

Study on modification of primary carbides and improvement of properties in H13 steel by CeO2 nanoparticles addition

The large primary carbides in H13 steel significantly affect its service life. In this study, pre-dispersion technology is used to disperse CeO2 nanoparticles, which are then introduced into H13 steel. The effects of CeO2 nanoparticles on the inclusions, primary carbides, microstructures, and properties of H13 steel are investigated. Ce-containing inclusions with size of 0.5–2 μm are generated and distributed uniformly in H13 steel owing to the reduction of CeO2 by Al and C. Both the dendrite structure and primary carbides in H13 steel are refined by CeO2 nanoparticles. The secondary dendrite arm spacing decreases from 13.51 ± 2.34 to 6.90 ± 1.23 μm. The size and number of primary carbides decrease from 1 to 5 to 1–3 μm, and from 1125 to 725/mm2, respectively. This is attributable to the disregistry of Ce-containing inclusions and primary carbides/austenite. The segregation of alloy elements in H13 steel is calculated using the Clyne–Kurz model. The properties of H13 steel are improved via the addition of CeO2; in particular, its tensile strength, total elongation rate, and hardness are 726.38 MPa, 23.43%, and 243.49, respectively, which corresponds to increases by approximately 5.58%, 8.27%, and 10.11%, respectively. The results can facilitate improvements to the performance of H13 steel and the development of rare earth steel.

Insights into the Effects of CeO2 Nanoparticles on Medium-Chain Carboxylates Production from Waste Activated Sludge

The synthesis of medium-chain carboxylates (MCCs) from waste-activated sludge (WAS) upgrading has received considerable attention. However, limited research has been conducted on the effects of CeO2 nanoparticles (NPs) on this process. This study showed that 1 mg/g−TS of CeO2 NPs improved the solubilization of WAS, resulting in higher production of MCCs. At 5 mg/g−TS, CeO2 NPs weakly inhibited 3 biological steps. Despite this, there was an enhancement in WAS solubilization, thus the overall production of MCCs was similar to the control. However, doses of CeO2 NPs ranging from 25–100 mg/g−TS were unable to offset biological inhibition, leading to a decrease in MCC production. The toxic mechanisms involved were not the generation of reactive oxygen species or Ce ions from CeO2 NPs to anaerobic sludge, but instead the decline of extracellular polymeric substance (EPS) and destruction of the cell membrane through physical penetration. Microbial community analysis confirmed that 1 mg/g−TS of CeO2 NPs increased the relative abundance of key bacteria involved in the anaerobic fermentation of WAS. The MCC microbe Clostridium sensu stricto was enriched in the control group, while the relative abundance of this genus was significantly reduced with 100 mg/g−TS CeO2 NPs.

Effects of CeO2 Nanoparticles on Nutritional Quality of Two Crop Plants, Corn (Zea mays L.) and Soybean (Glycine max L.)

With the widespread applications of manufactured nanoparticles (NPs), there are increasing concerns about their potential adverse effects on the environment and living systems. Many studies demonstrated that NPs could significantly affect the growth and development of crop plants. However, knowledge regarding the impacts of NPs on crop quality is rather limited. In this study, the effects of CeO2 NPs (25, 75, and 225 mg Ce/kg) and CeCl3 (25 mg Ce/kg) on the nutritional components of soil-cultivated corn and soybean plants were evaluated. Both treatments tended to decrease the dry weight of grain per plant, while only 225 mg/kg CeO2 NPs on soybean and CeCl3 on corn showed statistical significance compared with the respective control. CeO2 NPs at 225 mg/kg significantly decreased the content of starch in the corn kernels by 18.2% but increased total phenols in soybean seeds by 18.4%. Neither CeO2 NPs nor CeCl3 significantly affected the contents of minerals in corn kernels except for Zn. However, in the case of soybean, the two treatments tended to decrease the contents of P, Zn, Mn, and Mo but increase the content of S. Overall, the results suggest that CeO2 NPs and Ce3+ ions showed similar but not identical effects on corn and soybean plants. CeO2 NPs affect the nutritional quality of crop plants in a species-dependent manner.

Effect of CeO2 Nanoparticles on the Spread of Antibiotic Resistance in a Reclaimed Water-Soil-Radish System - Shenzhen City, Guangdong Province, China, April 2023.

The use of reclaimed water (RW) for irrigation in agricultural practices raises concerns regarding the dissemination of antibiotic resistance genes (ARGs) from soils to edible crops. The effectiveness of nanoparticles (NPs) in reducing antibiotic resistance in vegetables irrigated with RW remains largely unexplored. To investigate the effects, we conducted pot experiments in which radishes were planted in soil amended with CeO2 NPs using various application techniques. The abundance of ARGs was characterized using high-throughput quantitative PCR (HT-qPCR). Concurrently, we utilized 16S ribosomal RNA (rRNA) gene sequencing to evaluate the microbial community structure of both the rhizosphere soil and the endophytic compartment within the radishes. Employing bioinformatics analysis, we probed the potential mechanisms by which NPs influence the resistome within the reclaimed water-soil-radish system. Following the application of CeO2 NPs, there was a noticeable reduction in both the number and concentration of ARG genotypes in the rhizosphere soil, as well as within the radish. Concurrently, CeO2 NPs appeared to mitigate the propagation of ARGs within the reclaimed water-soil-radish system. The ability of CeO2 NPs to modulate the resistome is linked to alterations in microbial community structure. Soil treatment with NPs emerged as the most effective strategy for curbing the spread of ARGs. This finding provides a theoretical foundation for the development of nano-agricultural technologies aimed at controlling the proliferation of ARGs.

Effect of CeO2 nanoparticles on plant growth and soil microcosm in a soil-plant interactive system

The impact of CeO2 nanoparticles (NPs) on plant physiology and soil microcosm and the underlying mechanism remains unclear to date. This study investigates the effect of CeO2 NPs on plant growth and soil microbial communities in both the rhizosphere of cucumber seedlings and the surrounding bulk soil, with CeCl3 as a comparison to identify the contribution of the particulate and ionic form to the phytotoxicity of CeO2 NPs. The results show that Ce was significantly accumulated in the cucumber tissue after CeO2 NPs exposure. In the roots, 5.3% of the accumulated Ce has transformed to Ce3+. This transformation might take place prior to uptake by the roots since 2.5% of CeO2 NPs was found transformed in the rhizosphere soil. However, the transformation of CeO2 NPs in the bulk soil was negligible, indicating the critical role of rhizosphere chemistry in the transformation. CeO2 NPs treatment induced oxidative stress in the roots, but the biomass of the roots was significantly increased, although the Vitamin C (Vc) content and soluble sugar content were decreased and mineral nutrient contents were altered. The soil enzymatic activity and the microbial community in both rhizosphere and bulk soil samples were altered, with rhizosphere soil showing more prominent changes. CeCl3 treatment induced similar effects although less than CeO2 NPs, suggesting that Ce3+ released from CeO2 NPs contributed to the CeO2 NPs induced impacts on soil health and plant physiology.

Effect of CeO2 nanoparticles on the microstructure and properties of the NiCo-CeO2 composite coatings

The NiCo-CeO2 composite coatings were electrodeposited on copper substrate in Watts’ bath containing various CeO2 nanoparticle concentrations. The effect of CeO2 nanoparticles on the microstructure, surface residual stress and properties of NiCo-CeO2 composite coatings was studied. The nature and distribution of CeO2 nanoparticles in the NiCo-CeO2 composite coatings were analyzed by TEM. As the rise of CeO2 nanoparticle content in NiCo-CeO2 composite coatings, the microhardness of coating increased, which was because of the function of grain refinement and dispersion strengthening. Meanwhile, surface residual stress gradually increased as the rise of CeO2 nanoparticle content. Corrosion test result showed that increasing CeO2 nanoparticle content promoted the corrosion resistance of NiCo-CeO2 composite coatings. The NiCo-CeO2 composite coatings as the CeO2 nanoparticle concentration of 10 g/L had the highest corrosion resistance, which indicated that improvement of corrosion resistance needed a moderate amount of CeO2 nanoparticles. Particularly, the corrosion products were confirmed by XPS measurement, which demonstrated that CeO2 nanoparticles promoted the generation of corrosion products, resulting in the improved corrosion resistance.

Effects of CeO2 nano-particles on anti-aging performance of HDPE polymer during friction

The water-lubricated polymer stern tube bearing is a key-component which has great influences on operational reliability and safety of marine power systems. The poor thermal conductivity and frictional heat generated by friction easily cause severe deforming behaviours on the polymer bearing contacting surfaces, and lead to the high coefficient of friction as well as fluctuations. Therefore, for figuring out the tribological properties of polymer matrix composites after being modified by nano-fillers and conducted aging treatments, an array of high density polyethylene (HDPE) composites composed with CeO2 were manufactured and tested on a commercial tribo-tester. The results showed that the CeO2 nano-particles had a significant effect on the anti-aging property of HDPE and affected its tribology properties. Compared with the pure HDPE, CeO2 nano-particles could reduce the COF after aging, and the COF reduction rate reached maximum to 46.6% after aging for 25 d. The CeO2 nano-particles reduced the internal molecular chain fractures of the modified polymer under aging conditions, and slowed down the descending trends of the typical physical properties of polymer. The tribology properties of the modified polymer were enhanced by CeO2 nano-particles compared with the pure HDPE, and the reinforcement model was disclosed in the end. The knowledge gained herein will be useful for designing a new water lubricated bearing polymer with good anti-aging property for extending its applications under extreme circumstances.

Effects of CeO2 nanoparticles on the viabilities of neural PC12 and SH-SY5Y cells

To investigate the effects of cerium oxide (CeO2) nanoparticles on the viabilities of nerve cells PC12 and SH-SY5Y. CeO2 nanoparticles were synthesized, structures were characterized and properties were evaluated. PC12 cells and SH-SY5Y cells were treated with CeO2 nanoparticles at different concentrations (1, 2.5, 5, 10, 25, 50, 75, 100, 150 μg/ml) for 24 h and the cell viability was measured by MTT assay. Then PC12 cells and SH-SY5Y cells were co-treated with CeO2 and active oxygen scavenger NAC and the cells were stained with DCFH-DA probe for ROS. The number of cells and the fluorescence intensity were observed under a fluorescent inverted microscope. Differences were assessed by one-way ANOVA. After treatment with CeO2 nanoparticles, the viabilities of both PC12 cells (P＜0.01) and SH-SY5Y cells (P＜0.01) were decreased comparing with the control group. After staining with DCFH-DA probe, the fluorescence intensity of the nerve cells was enhanced depending on the concentration of CeO2 nanoparticles suggesting that CeO2 induced the generation of reactive oxygen species (ROS). The fluorescence intensity of PC12 cells was decreased after CeO2 nanoparticles (100 μg/ml) co-treatment with active oxygen scavenger NAC. Compared with CeO2 nanoparticles alone at 25 μg/ml (P＜0.01), 50 μg/ml (P＜0.01), 75 μg/ml (P＜0.01), 100 μg/ml (P＜0.01), the cell viability was significantly increased after co-treatment with NAC. CeO2 nanoparticles has a negative effect on the viabilities of nerve cells PC12 and SH-SY5Y, and the effect might be depend on ROS.

Physical Properties of Carbon Nanomaterials and Nanoceria Affect Pathways Important to the Nodulation Competitiveness of the Symbiotic N2 -Fixing Bacterium Bradyrhizobium diazoefficiens.

The pathogenicity and antimicrobial properties of engineered nanomaterials (ENMs) are relatively well studied. However, less is known regarding the interactions of ENMs and agriculturally beneficial microorganisms that affect food security. Nanoceria (CeO2 nanoparticles (NPs)), multiwall carbon nanotubes (MWCNTs), graphene nanoplatelets (GNPs), and carbon black (CB) have been previously shown to inhibit symbiotic N2 fixation in soybeans, but direct rhizobial susceptibility is uncertain. Here, Bradyrhizobium diazoefficiens associated with symbiotic N2 fixation in soybeans is assessed, evaluating the role of soybean root exudates (RE) on ENM-bacterial interactions and the effects of CeO2 NPs, MWCNTs, GNPs, and CB on bacterial growth and gene expression. Although bacterial growth is inhibited by 50 mg L-1 CeO2 NPs, MWCNTs, and CB, all ENMs at 0.1 and 10 mg L-1 cause a global transcriptomic response that is mitigated by RE. ENMs may interfere with plant-bacterial signaling, as evidenced by suppressed upregulation of genes induced by RE, and downregulation of genes encoding transport RNA, which facilitates nodulation signaling. MWCNTs and CeO2 NPs inhibit the expression of genes conferring B. diazoefficiens nodulation competitiveness. Surprisingly, the transcriptomic effects on B. diazoefficiens are similar for these two ENMs, indicating that physical, not chemical, ENM properties explain the observed effects.

Microstructural Changes and Mechanical Response of Aluminum-Based Composites Prepared with Dispersed CeO2 Nanoparticles

The effect of CeO2 nanoparticles on the microstructure of two different metal matrixes, AA2024 aluminum alloy and pure aluminum, were studied. The aluminum-based composites were synthesized by mechanical milling and subsequently sintering at 550°C under an argon atmosphere. The microstructural evolution of consolidated composites was evaluated by scanning electron microscopy, transmission electron microscopy, and X-ray diffraction. The experimental results revealed that the addition of CeO2 nanoparticles in the AA2024 alloy produced a dispersed needle-like Ce-Cu-rich phase that reduces the hardness of samples after sintering. On the contrary, the dispersion of CeO2 in pure aluminum shows significant improvement of hardness in comparison with the reinforced and unreinforced AA2024 aluminum alloy. During the sintering, the CeO2 nanoparticles show higher chemical stability in the aluminum matrix in comparison with the AA2024 matrix.

Effects of CeO2 nanoparticles on the algal composition and photosynthetic activity of phototrophic biofilm

The influences of CeO2 nanoparticles (NPs) on phototrophic biofilm were explored in terms of the algal composition and photosynthetic activity. Biofilms were cultivated in an artificial flume and exposure experiments were conducted with two levels of CeO2 NPs (0.05 and 0.5 mg/L) for 10 days. Results showed that 0.05 mg/L CeO2 NPs treatment altered the algal composition of biofilms, while the total Chl a and the photosynthetic activity maintained at the similar level as the control test. 5 mg/L CeO2 NPs not only changed the algal composition of biofilms, but also significantly decreased the photosynthetic activity, suggesting that high concentration of CeO2 NPs might lead to serious consequences to the primary production and nutrient cycling in aquatic environments.

Effect of CeO2 nanoparticles on Microstructure and Hardness of A6063 Aluminum Alloy.

Effect of CeO2 nanoparticles on Microstructure and Hardness of A6063 Aluminum Alloy.

Cerium oxide nanoparticles as potential antibiotic adjuvant. Effects of CeO2 nanoparticles on bacterial outer membrane permeability

BackgroundTherapeutic options against Multi Drug Resistant (MDR) pathogens are limited and the overall strategy would be the development of adjuvants able to enhance the activity of therapeutically available antibiotics. Non-specific outer membrane permeabilizer, like metal-oxide nanoparticles, can be used to increase the activity of antibiotics in drug-resistant pathogens. The study aims to investigate the effect of cerium oxide nanoparticles (CeO2 NPs) on bacterial outer membrane permeability and their application in increasing the antibacterial activity of antibiotics against MDR pathogens. MethodsThe ability of CeO2 NPs to permeabilize Gram-negative bacterial outer membrane was investigated by calcein-loaded liposomes. The extent of the damage was evaluated using lipid vesicles loaded with FITC-dextran probes. The effect on bacterial outer membrane was evaluated by measuring the coefficient of permeability at increasing concentrations of CeO2 NPs. The interaction between CeO2 NPs and beta-lactams was evaluated by chequerboard assay against a Klebsiella pneumoniae clinical isolate expressing high levels of resistance against those antibiotics. ResultsCalcein leakage increases as NPs concentrations increase while no leakage was observed in FITC-dextran loaded liposomes. In Escherichia coli the outer membrane permeability coefficient increases in presence of CeO2 NPs. The antibacterial activity of beta-lactam antibiotics against K. pneumoniae was enhanced when combined with NPs. ConclusionsCeO2 NPs increases the effectiveness of antimicrobials which activity is compromised by drug resistance mechanisms. The synergistic effect is the result of the interaction of NPs with the bacterial outer membrane. The low toxicity of CeO2 NPs makes them attractive as antibiotic adjuvants against MDR pathogens.

Effects of CeO2 nanoparticles on the HO-1, NQO1, and GCLC expression in the testes of diabetic rats.

CeO2 nanoparticles (CNPs) as effective ROS scavengers exhibit potent antioxidant activity. In this study the effect of CNPs investigated was on HO-1, NQO1, and GCLC expression in the streptozotocin (STZ)-induced diabetic rats. Twenty-four male Wistar rats were divided into 4 groups: controls did not receive any treatment; diabetic rats received STZ (60 mg/kg daily); CNPs group received CNPs 30 mg/kg daily for 2 weeks; and rats in STZ + CNPs group received CNPs 30 mg/kg daily for 2 weeks following STZ injection. Oxidative stress was evaluated by measurement of total antioxidant capacity (TAC) and total oxidative status (TOS levels). HO-1, NQO1, and GCLC expression was measured using quantitative real-time PCR. Following STZ injection, significant lower levels of TAC and higher levels of TOS were observed. CNPs could alleviate deleterious effects of diabetes through the enhancement of TAC levels and a significant decline in TOS levels. HO-1, NQO1, and GCLC expression in the diabetic rats were lower than controls. HO-1, NQO1, and GCLC was upregulated in the diabetic rats treated with CNPs. There were significant correlations between NQO1 and GCLC, NQO1 and HO-1, and between HO-1 and GCLC expression. Moreover, Nrf2 was associated with NQO1, GCLC, and HO-1 expression. CNPs as Nrf2 upregulator confer protection against oxidative stress in the testes of STZ-induced diabetic rats by upregulating HO-1, GCLC, and NQO1 cytoprotective genes.

Effects of CeO2 nanoparticles on bacterial community and molecular ecological network in activated sludge system

The increasing use of cerium oxide nanoparticles (CeO2 NPs) has caused concerns regarding their potential environmental risks. However, their effects on bacterial communities and network interactions in activated sludge process are still unclear. In this study, we carried out long-term exposure experiments (210 d) to investigate the influence of CeO2 NPs on wastewater treatment performance, bacterial community structure and network interactions in activated sludge systems. The results showed that long-term exposure to 1 mg/L CeO2 NPs induced the deterioration of denitrifying process, which was consistent with the inhibition of enzyme activities of nitrite oxidoreductase and nitrate reductase under CeO2 NPs. CeO2 NPs decreased the bacterial diversity and altered the overall bacterial community structure in activated sludge. Some dominant denitrifying bacteria, such as Flexibacter and Acinetobacter decreased significantly. Molecular ecological network analysis showed that CeO2 NPs decreased the network complexity of bacterial community, and probably promoted the competition in bacterial communities of activated sludge. These changes of denitrifying bacteria and the bacterial network may be relevant to the deterioration of denitrifying process. This study provides insights into how the bacteria community and their molecular ecological network respond to CeO2 NPs in activated sludge systems.

A high-performance flexible gas sensor based on self-assembled PANI-CeO2 nanocomposite thin film for trace-level NH3 detection at room temperature

A resistive-type flexible ammonia (NH3) sensor was proposed and developed in this work, which was prepared by depositing polyaniline-cerium dioxide (PANI-CeO2) nanocomposite thin film on flexible polyimide (PI) substrate through in-situ self-assembly method. The effect of CeO2 nanoparticles on the polymerization of aniline was studied by comparing the morphological, structural and chemical features of the pure PANI and PANI-CeO2 nanocomposite, and the dynamic polymerization processes were also recorded and investigated. In this process, an interesting phenomenon was found that the protonation and oxidation degrees of PANI in PANI-CeO2 nanocomposite were improved significantly according to the XPS spectra analysis, which should be ascribed to the synergetic oxidation of CeO2 nanoparticles and ammonium persulfate (APS). Meanwhile, the NH3-sensing performances of the pure PANI and PANI-CeO2 film sensors were evaluated at room temperature (∼25 °C), which showed that the PANI-CeO2 film sensor possessed enhanced response, reduced recovery time, perfect response-concentration linearity, good reproducibility, splendid selectivity, remarkable long-term stability, ultra-low detectable concentration (16 ppb) and theoretical detection limit (0.274 ppb), and outstanding flexibility without significant response decrease after 500 bending/extending cycles. It was speculated that the excellent sensing performances should probably benefit from the gas-sensing enhancement effect of p-n junction, the improved protonation degree and modified morphology of PANI by the addiction of CeO2 nanoparticles. And, the high flexibility might originate from the flexible structure of PANI chains, and the good adhesion and nano-mechanical performance of PANI-CeO2 film. Besides, the effect of relative humidity on the sensing properties of PANI-CeO2 film sensor was also discussed and analyzed. Therefore, the proposed high-performance flexible PANI-CeO2 thin film sensor holds great promise for application into hand-held or wearable electronic devices for trace-level NH3 detection at room temperature.

Optimisation of microstructure and corrosion resistance of Ni-Ti composite coatings by the addition of CeO2 nanoparticles

In present work, the ternary Ni-Ti-CeO2 composite coatings were electrodeposited on Al matrix composite (CNT/7075) in traditional Watts' solution containing various concentrations of CeO2 nanoparticles and constant concentration of Ti microparticles. The effects of CeO2 nanoparticles on microstructure and corrosion resistance of the obtained composite coatings were comprehensively investigated. The incorporation of moderate CeO2 nanoparticles (less than 10gL−1 in Watts' solution) gave rise to grain refinement, random-orientation growth of nickel deposit and smooth surface of the composite coating. Corrosion tests of the Ni-Ti-CeO2 composite coatings in 3.5wt% sodium chloride (NaCl) at 25°C illustrated the optimised microstructure favoured the enhancement of corrosion resistance. Further analyses of the corrosion behavior demonstrated that the embedded CeO2 nanoparticles facilitated the formation of a compact passive film on the surface of the composite coatings during corrosion and promoted the formation of TiO2 on the surface of Ti microparticles. The formation of TiO2 not only protected the Ti metal particles but also helped to improve the corrosion resistance of the composite coatings, because the TiO2 coated Ti microparticles decreased the attack probability of nickel deposits by corrosive medium. Typically, the Ni-Ti-CeO2 composite coating electrodeposited in Watts' solution containing 10gL−1 CeO2 nanoparticles possessed the best corrosion resistance and excessive CeO2 nanoparticles deteriorated the corrosion resistance.

Research on Sensitization Effect of Ceria Nanoparticles on Tin Oxide Wire-in-Tube Nanofibers

To elaborate the effect of CeO2 nanoparticles on the sensing properties of SnO2, CeO2-functionalized SnO2 wire-in-tube nanofibers (WITN) was prepared by electrospinning and subsequently impregnating treatment. The gas sensing studies revealed that the CeO2 loaded SnO2 WITN exhibited enhanced sensitivity to ethanol compared to the pristine SnO2. With increasing amount of CeO2, the response of nanocomposites increases firstly and then decreases. And the response of nanocomposites to ethanol reach maximum when the concentration of impregnated Ce (NO3)3·6H2O is 0.03 mol·L-1. To detail the sensing mechanism, the X-ray photoelectron spectroscopy was firstly employed to detect the variation in oxygen species corresponding to different amounts of CeO2, but no obviously changes in oxygen species was detected. Subsequently, it was found that the initial resistance of CeO2@SnO2 WITN was higher than pristine SnO2, which could be beneficial to the improvement of sensing properties. More importantly, oxygen vacancy (mainly offered by CeO2 nanoparticles) was proved to be positively correlated to their gas-sensing performance. In this work, the electronic sensitization mechanism based on CeO2 loaded SnO2 was detailed, which could help for the better understanding the sensitization effect of rare earth element on semiconductor oxides.