Cu-doped CeO2 Research Articles

Efficient electrocatalytic reduction of nitrate to ammonia using Cu–CeO2 solid solution

Electrocatalytic nitrate reduction reaction (EC-NITRR) is expected to replace Haber-Bosch process for green ammonia (NH3) production. Currently, many catalysts often result in low NH3 yields and low faraday efficiencies due to the lack of active sites. In this study, Cu-doped CeO2 solid solution catalyst was prepared for EC-NITRR using transition metal ions doping. The addition of Cu significantly improved the oxygen vacancy (Ov) concentration of CeO2 and provided more active sites for NO3− catalysis. Meanwhile, the internal charge transfer capability and surface catalytic kinetics of the catalyst are enhanced by the excellent redox capability of Ce3+ and Cu+. Compared with bare CeO2, the NH3 yield of 7% Cu–CeO2 increased by 1.88 times. This work provides new ideas for the design of green and efficient catalysts for EC-NITRR by identifying the role of Cu in the mechanism of doping regulation of CeO2.

Efficient simultaneous removal of diesel particulate matter and hydrocarbons from diesel exhaust gas at low temperatures over Cu–CeO2/Al2O3 coupling with dielectric barrier discharge plasma

Diesel particulate matter (DPM) and hydrocarbons (HCs) emitted from diesel engines have a negative affect on air quality and human health. Catalysts for oxidative removal of DPM and HCs are currently used universally but their low removal efficiency at low temperatures is a problem. In this study, Cu-doped CeO2 loaded on Al2O3 coupled with plasma was used to enhance low-temperature oxidation of DPM and HCs. Removals of DPM and HCs at 200 °C using the catalyst were as high as 90% with plasma but below 30% without plasma. Operando plasma diffuse reflectance infrared Fourier transform spectroscopy coupled with mass spectrometry was conducted to reveal the functional mechanism of the oxygen species in the DPM oxidation process. It was found that Cu–CeO2 can promote the formation of adsorbed oxygen ( – ) and terminal oxygen (M=O), which can react with DPM to form carbonates that are easily converted to gaseous CO2. Our results provide a practical plasma catalysis technology to obtain simultaneous removals of DPM and HCs at low temperatures.

Green synthesized Cu-doped CeO2 nanoparticles for Congo red dye adsorption and antibacterial action

The removal of pollutants from water bodies is crucial for the well-being of humanity and is a topic of global research. Researchers have turned their attention to green synthesized nanoparticles for wastewater treatment due to their eco-friendly nature, biocompatibility, and cost-effectiveness. This work demonstrates the efficient removal of organic dye and both gram-positive and gram-negative bacteria from water bodies using copper-doped cerium oxide nanoparticles synthesized with Murraya Koenigii extract. Characterized via various methods, the 15% copper doped cerium oxide nanoparticles (Cu 15% NPs) exhibited maximum Congo red dye adsorption (98% degradation in 35 min). Kinetic analysis favoured a pseudo-second-order model, indicating the chemical nature of adsorption. Equilibrium adsorption isotherms aligned with the Langmuir model, indicating homogenous monolayer dye adsorption on the doped adsorbent. The maximum uptake of adsorbate, Q m obtained from Langmuir model for Cu 15% NPs was 193 mg g−1. The study also showed enhanced antibacterial activity against Bacillus subtilis, Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa for Cu-doped ceria, attributed to generation of reactive oxygen species (ROS) induced by the redox cycling between Ce3+ and Ce4+. This substantiated that the green synthesized copper doped cerium oxide nanoparticles are potential candidates for adsorptive removal of Congo red dye and as antibacterial agents.

The pH-dependent multiple nanozyme activities of copper-cerium dioxide and its application in regulating intracellular oxygen and hydrogen peroxide levels

Cu doped CeO2 (Cu-CeO2) nanoparticles were synthesized via the hydrothermal method, exhibiting multiple nanozyme activities such as good oxidase-like (OXD), peroxidase-like (POD) and catalase-like (CAT) activities. These Cu-CeO2 nanoparticles were successfully utilized to modulate the levels of oxygen and hydrogen peroxide in cells. The OXD and POD mimics showed optimal at pH of 3.5 and 4.0, but their activities significantly decreased under neutral or slightly acidic conditions. On the other hand, the CAT activity was excellent at pH 6.5, while the OXD and POD mimics were less effective. These findings demonstrated that nanozyme activity of Cu-CeO2 nanoparticles is pH-dependent. Consequently, within the microenvironment of tumor cells, the CAT can efficiently catalyze the conversion of H2O2 into O2, unaffected by H2O2/O2 consuming mimics. Both oxygen indicator and oxygen tester measurements confirmed a significant increase in O2 levels in phosphate-buffered saline (PBS). Furthermore, confocal microscopic imagings using fluorescence probes for H2O2 and O2 validated the variations of H2O2/O2 in cells. This study highlights the ability of Cu-CeO2 to regulate intracellular reactive oxygen levels and its tremendous potential in nanotherapy and alleviating tumor hypoxia.

Observation of structural, optical, electrical and magnetic properties of ternary copper-doped CeO2/GO/SrTiO3 nanocomposites

A ternary system involving copper-substituted ceria (Cu:CeO2)0.95−y(GO)y(SrTiO3)0.05 nanocomposite where the GO concentration (y) is varied between 0.15 and 0.30. The innovation of this work lies in the purposeful assembly of the nanocomposite using a grinding method, which was optimized through the individual fabrication of Cu-doped CeO2 with different CuO concentrations. In the first, Cu-doped CeO2 with various CuO concentrations (x = 0.0, 0.05, 0.1, 0.2, and 0.3) was first individually fabricated based on a sol–gel auto-combustion strategy to optimize the best ratio. The XRD profiles confirm the successful fabrication of cubic cerium (IV) oxide CeO2 using glycine as a fuel at an annealing temperature of 400 °C for 2 h. AC conductivity was investigated for both Cu-doped CeO2 and the ternary nanocomposite over a wide frequency range (10–1 to 107 Hz) at room temperature. The conductivity showed lower values for CeO2 doped with 0.05, 0.2, and 0.3 wt% CuO, whereas it showed its maximum values upon doping with 0.1 wt% CuO. Interestingly, the conductivity of graphene oxide–doped CeO2 was 103 times higher than that of pure CeO2, i.e., it increased from 1.7 × 10–6 to 2 × 10–3 S/cm. The magnetic-field dependence of MS of the ternary Cu-doped CeO2/GO/SrTiO3 nanocomposites showed a systematic increase in MS as the Cu2+ ion content increased. This strengthens the ferromagnetism in our samples as Cu2+ ion content increases.

Morphological optimized CeO2 and Cu-doped CeO2 nanocrystals for hydrogen production by solar photo-thermochemical water splitting based on surface photoinduced oxygen vacancies

Photo-thermochemical (PTC) reaction produces hydrogen by water splitting through the consumption of surface photoinduced oxygen vacancies (VOs). In this study, CeO2 and Cu-doped-CeO2 were synthesized with typical different morphologies of nanorods and nanospheres and different crystallite sizes. These factors, i.e. microstructure, crystalline size and Cu doping were proven to influence the physical properties and photoresponse performance of CeO2 which affected the generation of surface photoinduced VOs and their reactions of hydrogen production in PTC. Cu-doped CeO2 nanospheres with smaller crystallite size demonstrated the best catalytic activity with the largest H2 yield of 18.4 μmol g-1h−1. The electron paramagnetic resonance and Ultraviolet–visible diffuse reflection spectroscopy analysis showed that the VOs generation of nanospheres was strengthened compared to nanorods when the physical characteristics were similar. The positive correlation between the change in physical properties and yield supports its importance in VOs consumption in the thermochemical process. The smaller crystallite size of the nanospheres exhibited better porous properties and specific surface area, which facilitated thermochemical reaction. The doping significantly reduces the band gap of the sample, enhances the light absorption capacity and significantly increases the H2 yield of CeO2.

Transition metal doped CeO2 for photocatalytic removal of 2-chlorophenol in the exposure of indoor white light and antifungal activity.

Besides natural sunlight and expensive artificial lights, economical indoor white light can play a significant role in activating a catalyst for photocatalytic removal of organic toxins from contaminated water. In the current effort, CeO2 has been modified with Ni, Cu, and Fe through doping methodology to study the removal of 2-chlorophenol (2-CP) in the illumination of 70W indoor LED white light. The absence of additional diffractions due to the dopants and few changes such as reduction in peaks' height, minor peak shift at 2θ (28.525°) and peaks' broadening in XRD patterns of modified CeO2 verifies the successful doping of CeO2. The solid-state absorption spectra revealed higher absorbance of Cu-doped CeO2 whereas a lower absorption response was observed for Ni-doped CeO2. An interesting observation regarding the lowering of indirect bandgap energy of Fe-doped CeO2 (∼2.7eV) and an increase in Ni-doped CeO2 (∼3.0eV) in comparison to pristine CeO2 (∼2.9eV) was noticed. The process of e -- h + recombination in the synthesized photocatalysts was also investigated through photoluminescence spectroscopy. The photocatalytic studies revealed the greater photocatalytic activity of Fe-doped CeO2 with a higher rate (∼3.9 × 10-3min-1) among all other materials. Moreover, kinetic studies also revealed the validation of the Langmuir-Hinshelwood kinetic model (R2 = 0.9839) while removing 2-CP in the exposure of indoor light with a Fe-doped CeO2 photocatalyst. The XPS analysis revealed the existence of Fe3+, Cu2+ and Ni2+ core levels in doped CeO2. Using the agar well-diffusion method, the antifungal activity was assessed against the fungus M. fructicola and F. oxysporum. Compared to CeO2, Ni-doped CeO2, and Cu-doped CeO2 nanoparticles, the Fe-doped CeO2 nanoparticles have outstanding antifungal properties.

A novel MOF-derived strategy to construct Cu-doped CeO2 supported PdCu alloy electrocatalysts for hydrogen evolution reaction

Hydrogen evolution reactions (HER) via water splitting is of significance for electricity-to-fuel conversion. The pursuits of rationally design and facile synthesis method for efficient HER catalysts have long been a subject of interest. In this work, a bimetallic MOF-derived strategy was constructed to realize doping and alloying of transition metal in parallel and Pd-CuCeOx catalyst was prepared, in which Cu served as doping element in CeO2 and secondary metal in Pd-Cu alloy. For the as-synthesized Pd-CuCeOx, an overpotential of 109 mV is needed to reach a current density of 10 mA cm−2 with a Tafel slope of only 30.9 mV dec−1. With the low content of precious metal, Pd-CuCeOx exhibited a high TOF value of 6.99 s−1, which is about 3.5 times higher than that of commercial Pt/C. The improved HER performance is attributed to the d-band structure modified by alloying and the enhanced electronic coupling caused by doping.

Hydride Generation on the Cu-Doped CeO2(111) Surface and Its Role in CO2 Hydrogenation Reactions

Ceria-based catalysts exhibit great activity in catalyzing selective hydrogenation of CO2 to methanol. However, the underlying mechanism of this reaction, especially the generation of active H species, remains unclear. In this work, we performed extensive density functional theory calculations corrected by on-site Coulomb interaction (DFT + U) to investigate the H2 dissociation and the reaction between the active H species and CO2 on the pristine and Cu-doped CeO2(111) (denoted as Cu/CeO2(111)) surfaces. Our calculations evidenced that the heterolytic H2 dissociation for hydride generation can more readily occur on the Cu/CeO2(111) surface than on the pristine CeO2(111) surface. We also found that the Cu dopant can facilitate the formation of surface oxygen vacancies, further promoting the generation of hydride species. Moreover, the adsorption of CO2 and the hydrogenation of CO2 to HCOO* can be greatly promoted on the Cu/CeO2(111) surface with hydride species, which can lead to the high activity and selectivity toward CO2 hydrogenation to methanol.

Development of Cu-doped CeO2 nanospheres mimic nanozyme-based immunoassay for the specific screening of Bacillus cereus.

Due to the highly similar genetic background, it is difficult to distinguish Bacillus cereus (B. cereus) with other members of B. cereus group. Herein, an antibody-based colorimetric immunoassay using Cu-doped CeO2 nanospheres as peroxidase mimics was developed for the detection of B. cereus in food. First, monoclonal antibodies (mAbs) and polyclonal antibody (pAb) with good specificity to B. cereus were prepared and characterized. Second, the regular-shaped hollow Cu/CeO2 nanospheres with highly catalytic activity and biocompatibility were synthesized as mimic nanozymes to capture secondary antibody. Finally, a sandwich colorimetric immunoassay for the specific and sensitive detection of B. cereus was developed, showing linear detection range from 3.2 × 102 to 1 × 105CFU/mL and a limit detection of 1.7 × 102CFU/mL. The developed immunoassay holds great potential as an effective tool for detecting B. cereus in food poisoning.

A Novel Mof-Derived Strategy to Construct Cu-Doped Ceo2 Supported Pdcu Alloy Electrocatalysts for Hydrogen Evolution Reaction

A Novel Mof-Derived Strategy to Construct Cu-Doped Ceo2 Supported Pdcu Alloy Electrocatalysts for Hydrogen Evolution Reaction

Carbon nitride-supported CuCeO2 composites derived from bimetal MOF for efficiently electrocatalytic nitrogen fixation

Development of an efficient catalyst for ammonia preparation through electrochemical nitrogen fixation is significant and desirable to relieve the tremendous energy-consumption by the conventional Haber-Bosch process. Herein, the abundant oxygen vacancy-containing CuCeO2@NC composite (denoted as Cu-doped CeO2 nanoparticles supported on carbon nitride) was fabricated by annealing melamine-incorporated metal-organic framework (MOF) of CuCe-BTC (BTC = 1,3,5-benzenetricarboxylic acid) under the reducing atmosphere of 10% H2/Ar. The optimized composite of Cu0·1CeO2@NC achieved a high selectivity and an outstanding electrocatalytic activity with NH3 yield rate of 44.5 μg h−1 mgcat.−1 at −0.5 V versus a reversible hydrogen electrode, surpassing most of the reported electrocatalysts and its analogues without copper and nitrogen atoms as dopants. The favorable performance of Cu0·1CeO2@NC would be ascribed to the synergistic effect of the rich oxygen vacancies and the optimal electrical structure induced by heteroatom doping, further confirmed by X-ray photoelectron spectroscopy (XPS), electron paramagnetic resonance (EPR) spectroscopy, and Raman spectra. Moreover, the great electrochemical selectivity and durability for the longtime electrolysis had been demonstrated. This work offered an insight that the electrocatalytic performance would be regulated by heteroatomic dopants and oxygen vacancy toward MOF-derived materials.

Oxygen-vacancy mediated acidity and redox properties on WOx/Cu-doped CeO2 for the removal of NOx

Acidity and redox properties of the catalyst are two crucial factors affecting the performance of NH3-SCR. Herein, we design a novel WOx/Cu-CeO2 oxide catalyst in which the WOx species are highly dispersed on the {111}/{100}-terminated surface of Cu-doped CeO2 nanospheres, which exhibits great deNOx activity advantage and wide operating temperature window (200–400 °C, over 85% NOx conversion with a gas hourly space velocity (GHSV) of 60,000 h−1), as well as good sulfur resistance and N2 selectivity. The relationship among the composition, acidity and redox properties of the WOx/Cu-CeO2 catalyst is established in the NH3-SCR reaction. The combined experimental studies and spectroscopic characterization reveal that the introduction of Cu into the lattice of CeO2 not only increases the surface Ce3+ and oxygen vacancy concentration but also provides more sites for capture and dispersion of WOx species, thus mediating and improving the Lewis and Brønsted acid sites and reducibility of catalyst. XPS and DFT calculations further demonstrate that electronic interaction between WOx and Cu-doped CeO2 is enhanced duo to the existence of interactions of short-range Ce-O-Cu and Ce-O-W. Moreover, the NH3-SCR reaction over WOx/Cu-CeO2 may follow both Langmuir-Hinshelwood and Eley-Rideal reaction pathway according to the in situ DRIFTS.

Design Aspects of Doped CeO2 for Low-Temperature Catalytic CO Oxidation: Transient Kinetics and DFT Approach.

CO elimination through oxidation over highly active and cost-effective catalysts is a way forward for many processes of industrial and environmental importance. In this study, doped CeO2 with transition metals (TM = Cu, Co, Mn, Fe, Ni, Zr, and Zn) at a level of 20 at. % was tested for CO oxidation. The oxides were prepared using microwave-assisted sol–gel synthesis to improve catalyst’s performance for the reaction of interest. The effect of heteroatoms on the physicochemical properties (structure, morphology, porosity, and reducibility) of the binary oxides M–Ce–O was meticulously investigated and correlated to their CO oxidation activity. It was found that the catalytic activity (per gram basis or TOF, s–1) follows the order Cu–Ce–O > Ce–Co–O > Ni–Ce–O > Mn–Ce–O > Fe–Ce–O > Ce–Zn–O > CeO2. Participation of mobile lattice oxygen species in the CO/O2 reaction does occur, the extent of which is heteroatom-dependent. For that, state-of-the-art transient isotopic 18O-labeled experiments involving 16O/18O exchange followed by step-gas CO/Ar or CO/O2/Ar switches were used to quantify the contribution of lattice oxygen to the reaction. SSITKA-DRIFTS studies probed the formation of carbonates while validating the Mars–van Krevelen (MvK) mechanism. Scanning transmission electron microscopy-high-angle annular dark field imaging coupled with energy-dispersive spectroscopy proved that the elemental composition of dopants in the individual nanoparticle of ceria is less than their composition at a larger scale, allowing the assessment of the doping efficacy. Despite the similar structural features of the catalysts, a clear difference in the Olattice mobility was also found as well as its participation (as expressed with the α descriptor) in the reaction, following the order αCu > αCo> αMn > αZn. Kinetic studies showed that it is rather the pre-exponential (entropic) factor and not the lowering of activation energy that justifies the order of activity of the solids. DFT calculations showed that the adsorption of CO on the Cu-doped CeO2 surface is more favorable (−16.63 eV), followed by Co, Mn, Zn (−14.46, −4.90, and −4.24 eV, respectively), and pure CeO2 (−0.63 eV). Also, copper compensates almost three times more charge (0.37e−) compared to Co and Mn, ca. 0.13e− and 0.10e−, respectively, corroborating for its tendency to be reduced. Surface analysis (X-ray photoelectron spectroscopy), apart from the oxidation state of the elements, revealed a heteroatom–ceria surface interaction (Oa species) of different extents and of different populations of Oa species.

Mo,Cu-doped CeO2 as Anode Material of Solid Oxide Fuel Cells (SOFCs) using Syngas as Fuel

Mo, Cu-doped CeO2 (CMCuO) nanopowders were synthesized by the nitrate-fuel combustion method aiming to improve the electrical and electrochemical properties of its Mo-doped CeO2 (CMO) parent by the addition of copper. An electrical conductivity of ca. 1.22·10−2 S cm−1 was measured in air at 800°C for CMCuO, which is nearly 10 times higher than that reported for CMO. This increase was associated with the inclusion of copper into the crystal lattice of ceria and the presence of Cu and Cu2O as secondary phases in the CMCuO structure, which also could explain the increase in the charge transfer activities of the CMCuO based anode for the hydrogen and carbon monoxide electro-oxidation processes compared to the CMO based anode. A maximum power density of ca. 120 mW cm−2 was measured using a CMCuO based anode in a solid oxide fuel cell (SOFC) with YSZ electrolyte and LSM-YSZ cathode operating at 800°C with humidified syngas as fuel, which is comparable to the power output reported for other SOFCs with anodes containing copper. An increase in the area specific resistance of the SOFC was observed after ca. 10 hours of operation under cycling open circuit voltage and polarization conditions, which was attributed to the anode delamination caused by the reduction of the Cu2O secondary phase contained in its microstructure. Therefore, the addition of a more electroactive phase for hydrogen oxidation is suggested to confer long-term stability to the CMCuO based anode. Keywords: SOFC Anode Material, Ceria, Molybdenum Oxide, Copper Nanoparticles, Syngas Fuel

Mechanism of copper doping in cerium(IV) oxidepowder and its effect on 3–5 μm infrared emissivity

In this study, Ce1−xCuxO2−x (x = 0, 0.01, 0.03, 0.05, 0.07) samples were prepared by hydrothermal method. The structure, microstructure, and elemental composition of the powders were characterized by X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray spectroscopy, whereas the electrical conductivity, ultraviolet–visible absorption spectroscopy, and infrared emissivity at 3–5 μm were measured as well. Moreover, the effects of Cu2+ doping concentration on the microstructure, morphology, bandgap, conductivity, and infrared emissivity of Cu-doped CeO2 powders were systematically studied. The effects of Cu2+ doping on infrared reflection and absorption in a 3–5 μm band and their mechanisms were explained based on electromagnetic theory, lattice vibration absorption, and free carrier absorption. Our result indicated that the emissivity of 1% Cu-doped powder reached the lowest emissivity of 0.200 at 800 °C. When the doping concentration was above 1%, the curve of infrared emissivity versus temperature exhibited a “U” shape, with the minimum point shifting towards the low-temperature region with the increase of Cu doping amount. This phenomenon was attributed to the different enhancement amplitude of reflectivity and absorbance of CeO2 powder by Cu2+ at different temperatures.

Promoting effect of Cu-doping on catalytic activity and SO2 resistance of porous CeO2 nanorods for H2S selective oxidation

A facile procedure for doping copper species into CeO2 lattices to prevent ceria from being deactivated and to offer additional active sites for selective H2S oxidation is reported here. Among the prepared catalysts, porous 10Cu/Ce nanorods with well-defined (100) and (110) reactive planes display excellent catalytic performance, exhibiting H2S conversion and sulfur selectivity of 100% at 220 °C, which is higher than those of most reported Ce-based catalysts. More importantly, electron transfer from Cu+ to Ce4+ suppresses the transfer of electrons from SO2 to Ce4+, leading to inhibition of SO2 oxidation to surface sulfate , which could deactivate the catalyst. Overall, the results of systematic experimental and theoretical studies prove that copper doping effectively promotes the formation of oxygen vacancies and resistance against SO2 poisoning. Furthermore, through in situ diffuse reflection infrared Fourier transform spectroscopy investigation and density functional theory calculations, the reaction intermediates in selective H2S oxidation and mechanism of SO2 resistance over the Cu-doped CeO2 catalysts are revealed.

Selective synthesis of imines by direct oxidative coupling of amines on Cu-doped CeO2 catalysts

The study and development of CeO2 nanocrystals containing transition-metal species are of crucial importance for understanding the effect of transition-metal species on their catalytic activity. In this work, CeO2 nanocrystals containing only 0.61 wt% Cu have been demonstrated as an effective catalyst for imine synthesis from amines at 110 °C using NHPI as radical initiator and air as oxidant. Especially, Cu-doped CeO2 nanocrystals after thermal treatment at 300 °C for 2 h show high conversion (97.8%) and high selectivity (98.6%) for the synthesis of N-benzylidene benzylamine from benzylamine, as well as acceptable yield for the synthesis of several other kinds of imines from amines. The Cu-doped CeO2 nanocrystals also exhibited excellent cycling stability for at least four cycles with only a slightly decreased yield. It has been demonstrated that the high catalytic activity of Cu-doped CeO2 can be ascribed to the highly dispersed Cu species and abundant oxygen vacancies on their surfaces which activated the NHPI and O2 and promoted the adsorption/conversion of amine.

Ce1-x O₂Cux Nanoparticles: Synthesis, Characterization and Catalytic Activity for Phenol Degradation.

Solid solutions of CuO in CeO₂ have been prepared by the solution combustion method. This method allows the Cu2+ ions to dissolve into CeO₂ lattice instead of Ce4+ ions. This creates charge imbalance and lattice distortion in CeO₂ because of which oxygen vacancies are produced. The presence of Cu in ceria causes decrease in lattice parameters, smaller crystallites, and larger surface area. Both techniques XRD and Raman spectroscopy confirm the presence of cubic phase of CeO₂ with fluorite structure and they also show a peak shift after the introduction of Cu which is an indication of the total symmetry breaking of ceria structure. This may be related with the partial substitution of Ce4+ by Cu2+ cations in the CeO₂ lattice. TEM analysis results provide an average size of 27.4 nm for Cu-doped CeO₂ particles. XPS confirms the Cu2+ species in Cu-doped sample. The prepared Cu-Ce materials are explored for phenol degradation. The effect of initial phenol concentration, pH and catalyst amount on phenol degradation is investigated. It is observed that with increase in an initial phenol concentration, the degradation efficiency decreased. The maximum degradation efficiency is observed at pH 3 and 0.5 g/L amount of Cu-doped CeO₂ catalyst.

Controllable synthesis of transition metal ion-doped CeO2 micro/nanostructures for improving photocatalytic performance

Ceria (CeO2) micro/nanostructures with various sizes and shapes were successfully synthesized by doping with a series of transition metal ions without any surfactant or template. The crystal structure, morphology, and photocatalytic performance of CeO2 and Co-, Zr-, Cu-doped CeO2 were characterised. The lattice parameters, which indicate the crystal structure distortion and change of Ce4+, were changed by incorporating a transition metal into the CeO2. Doping with transition metal ion could broaden the absorption range from ultraviolet to visible region and enhance the concentration of oxygen vacancies, which exhibited a significantly lower optical band than pure CeO2. The photocatalytic studies revealed that CeO2 with a spate of oxygen vacancies displayed a higher photocatalytic activity than pure CeO2 in degrading the organic pollutant rhodamine B (RhB). Furthermore, the O2− and OH radicals formed during photocatalysis process were revealed by means of nitrotetrazolium blue chloride (NBT) reduction method and a terephthalic acid (TA) fluorescence probe method, respectively, which discovers that radicals were crucial for the degradation of RhB. The H2-TPR confirmed that a small amount of transition metal ions significantly affected the oxidation state of the surface cations and oxygen vacancies. This study clearly reveals the effects of different transition metal ion dopants on the morphologies and photocatalytic performance of transition metal ion-doped CeO2 micro/nanostructures.