Large Amount Of Oxygen Vacancies Research Articles

Synchronous construction of oxygen vacancies and phase junction in TiO2 hierarchical structure for enhancement of visible light photocatalytic activity

Oxygen vacancy defect and phase junction in semiconductor oxides play crucial role in determining their electronic structure, light absorption, photocatalytic activity, etc. Herein, we reported a facile molten salt (MS) calcination strategy for synchronously constructing oxygen vacancies and phase junction in TiO2 hierarchical structure. Flower-like TiO2 hierarchical structure were firstly synthesized via solvothermal method by adjusting the volume ratio of acetic acid (HAc) to N, N-dimethyl formamide (DMF) and then were subjected to MS calcination treatment. EPR, Raman and XPS results demonstrated that large amount of oxygen vacancies was formed on the surface of TiO2 hierarchical structure after MS calcination treatment. Meanwhile, the presence of oxygen vacancies resulted in the formation of phase junction. More importantly, the flower-like hierarchical structures were well maintained in the MS calcined samples, avoiding serious sintering during the calcination process. The synergistic effect of oxygen vacancies and phase junction not only extends the visible light adsorption range, but also promotes the separation of photogenerated electrons and holes, thereby greatly increasing the visible light photocatalytic activity. The highest photocatalytic activity was achieved for the MS calcined sample at 400 °C, which was about 5.5 folds higher than that calcined in air. This work provides a facile approach for synchronously constructing oxygen vacancies and phase junction in semiconductor oxides with special morphologies.

Fabrication of a Micro-Electromechanical System-Based Acetone Gas Sensor Using CeO2 Nanodot-Decorated WO3 Nanowires.

Preparation of reliable, stable, and highly responsive gas-sensing devices for the detection of acetone has been considered to be a key issue for the development of accurate disease diagnosis systems via exhaled breath. In this paper, novel CeO2 nanodot-decorated WO3 nanowires are successfully synthesized through a sequential hydrothermal and thermolysis process. Such CeO2 nanodot-decorated WO3 nanowires exhibited a remarkable enhancement in acetone-sensing performance based on a miniaturized micro-electromechanical system device, which affords high response (S = 1.30-500 ppb, 1.62-2.5 ppm), low detection limit (500 ppb), and superior selectivity toward acetone. The improved performance of the acetone sensor is likely to be originated from the fast carrier transportation of WO3 nanowires, the formation of WO3-CeO2 heterojunctions, and the existence of large amounts of oxygen vacancies in CeO2. The improved reaction thermodynamics and sensing mechanisms have also been revealed by the specific band alignment and X-ray photoelectron spectroscopy analysis.

Bionic Preparation of CeO2-Encapsulated Nitrogen Self-Doped Biochars for Highly Efficient Oxygen Reduction.

This study reports the superior performance of novel carbonaceous materials, CeO2-encapsulated nitrogen-doped biochars [BC-Ce-X (X = 1 and 2)], for oxygen reduction reaction (ORR). The biomass precursor of this value-added biochar material was biomimetically prepared via a hydroponic operation in the Ce-enriched solution. The characterization results showed that CeO2 with large amounts of oxygen vacancies was stably embedded in the N self-doped biochars during the pyrolytic processes. The measured specific surface areas of cerium-free biochar (BC sample), BC-Ce-1, and BC-Ce-2 were 79, 566, and 518 m2/g, respectively. The BC-Ce-X (X = 1 and 2) showed excellent ORR performances with onset potentials of ∼0.90-0.91 V, which outperformed the commercial 10 wt % Pt/C and BC. Compared with Pt/C, the BC-Ce-2 had better methanol tolerance and stability. Also, BC-Ce-2 displayed excellent electrochemical activity for Zn/air batteries. Controlled experiments and density functional theoretical calculations illustrated the synergistic effect between the pyri-N/C centers and CeO2 with oxygen vacancies in ORR. The Lewis base sites, created by pyri-N and oxygen vacancies, greatly facilitated the chemisorption of O2 molecules.

Copper substituted zinc ferrite with abundant oxygen vacancies for enhanced ciprofloxacin degradation via peroxymonosulfate activation

In this paper, copper substituted zinc ferrite (ZCFO) catalyst with rich oxygen vacancies (OVs) was synthesized via a simple one pot sol-gel combustion method, and firstly used for peroxymonosulfate (PMS) activation to degrade a typical antibiotic ciprofloxacin (CIP). Only ∼15 min was required to achieve 96.6% of CIP degradation using ZCFO as the catalyst, and the pseudo-first-order reaction constant was about 95 times higher than that of conventional zinc ferrite (1.90 min−1 vs 0.02 min−1). ZCFO catalyst showed great stability and reusability based on the successive degradation cycles and could be easily recovered through magnetic separation. Besides, the effects of catalyst loading, PMS concentration, reaction temperature, initial solution pH, coexisting anions and humic acid (HA) on CIP degradation were systematically investigated. Radical quenching tests and electron paramagnetic resonance (EPR) revealed that sulfate radical (SO4-.), hydroxyl radical (OH∙), superoxide radical (O2∙-) and singlet oxygen (1O2) were involved in the ZCFO/PMS system, among which O2∙- and 1O2 were the dominant reactive oxygen species (ROS). The excellent catalytic activity of ZCFO was ascribed to the dual active sites of Fe and Cu and large amount of OVs after Cu substitution, which was beneficial to generate ROS for CIP removal.

A-site deficient/excessive effects of LaMnO3 perovskite as bifunctional oxygen catalyst for zinc-air batteries

Recently, many works have demonstrated that tuning the A-site deficient and excessive stoichiometry can yield the positive effects on the catalytic activity of the ABO3 perovskite toward oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). Whereas, the universality of the deficient or excessive effects and their resulting improving mechanisms on ABO3 perovskite are still ambiguous and need to be clarified. In this work, the simplest Mn-based perovskite (LaMnO3) is selected to elucidate the deficient/excessive effects and improving mechanisms on both ORR and OER. We find that A-site deficient stoichiometry is favor to the catalytic activity and stability of LaMnO3 toward both ORR and OER, whereas A-site excessive stoichiometry is deleterious to the oxygen catalytic activity and stability of LaMnO3. The high oxygen catalytic activity of La0·9MnO3 (La90) with A-site deficiency toward ORR and OER can be related to its proper Mn cation valence, large amount of oxygen vacancies, upper shift of d-band center and strong adsorption capacity to oxygenated species. The results of this work highlight the A-site deficient Mn-based perovskite as the high efficient and commercially viable bifunctional catalyst for aqueous and solid-state flexible zinc-air battery (ZAB) applications.

Defect and strain modulated highly efficient ZnO UV detector: Temperature and low-pressure dependent studies

ZnO, a wide bandgap (~3.3 eV) material, can be used for ultraviolet photodetection. We have deposited ZnO thin-films on glass substrates by an automated ultrasonic spray pyrolysis system. X-ray diffraction (XRD), Raman spectroscopy suggest hexagonal wurtzite phase of prepared film and scanning electron microscope reveals its microflower like structure. The Photodetector devices have been fabricated in metal–semiconductor-metal (M−S−M) configuration. A highest responsivity of 24.38 A W−1 has been achieved at an applied bias of 5 V with the corresponding external quantum efficiency (EQE) value of 8283% for 365 nm UV irradiation. On/Off ratio of the device is ~ 454 even for a low UV intensity (1.66 mW cm−2) and the corresponding detectivity of the UV photodetector device is ~ 4.6 × 1012 cm Hz1/2 W−1. The observed high value of responsivity has been assigned to a large amount of oxygen vacancy in ZnO microflowers. Oscillation in photocurrent has been observed at low air pressure and has been assigned to a competitive dynamic process of absorption and desorption oxygen on the ZnO surface. Temperature-dependent optoelectrical properties have been analyzed based on trapping-detrapping of charge carriers in defect states and their interactions with lattice phonons.

Spark Plasma Sintering Treatment for Introduction of Oxygen Vacancy in Pt Dispersed SrTiO3 for Increasing Photocatalytic Water Splitting Activity

AbstractSpark plasma sintering (SPS) treatment was studied for Pt dispersed SrTiO3 as photocatalytic water splitting catalyst. The oxygen vacancy was introduced by SPS treatment and it was found that H2 formation rate was increased by SPS treatment since large amount of oxygen vacancy was introduced. H2 formation rate became the highest (6.15 mmol h−1 g−1) at 2.5 wt% Pt dispersed on SrTiO3 and this H2 formation rate was almost double of Pt loaded SrTiO3 and O2 formation rate was also much increased (5.66 mmol h−1 g−1). ESR measurement suggests that amount of Ti3+ was intense after SPS treatment with 2.5 wt% Pt. Therefore, it seems that the oxygen vacancy introduced by SPS treatment effectively worked for charge separation and photocatalytic activity of SrTiO3 to water splitting was increased.

P‐1.13: The Conductivity Modulation of Amorphous Zinc Tin Oxide Thin Film by aluminum (Al) reaction method

We propose a method to form low‐resistance amorphous zinc tin oxide thin film (a‐ZTO) by aluminum (Al) reaction method. After the optimized reaction process, a‐ZTO film exhibits a low sheet resistance of 0.71(KΩ/□). The metallic tin and the large amount of oxygen vacancies formed on the surface of a‐ZTO film contribute to the high conductivity. An optimized aluminum reaction method for fabrication of low‐resistance with high thermal stability a‐ZTO film is well demonstrated.

Local and Average Structure of Yb-Doped Ceria through Synchrotron and Neutron Pair Distribution Function

As transport properties of doped ceria electrolytes depend significantly on the nature of the dopant and the defectivity, the design of new materials and devices requires proper understanding of the defect structure. Among lanthanide dopants, Yb shows some peculiar characteristics that call for a possible different defect structure compared to Gd and Sm conventional dopants, which could be linked to its poorer performance. For this purpose, we combine synchrotron and neutron powder diffraction exploiting the Rietveld and Pair distribution Function. By increasing its concentration, Yb produces qualitatively the same structural distortions as other dopants, leading to a domain structure involving the progressive nucleation and growth of nanodomains with a Yb2O3-like (C-type) structure hosted in a fluorite CeO2 matrix. However, when it comes to growing the C-type nanodomains into a long-range phase, the transformation is less pronounced. At the same time, a stronger structural distortion occurs at the local scale, which is consistent with the segregation of a large amount of oxygen vacancies. The strong trapping of VOs by Yb3+ explains the poor performance of Yb-doped ceria with respect to conventional Sm-, Gd-, and Y-doped samples at equal temperature and dopant amount.

Low Hysteresis Perovskite Solar Cells Using an Electron-Beam Evaporated WO3–x Thin Film as the Electron Transport Layer

Perovskite solar cells utilize metal oxide thin films as electronic transport for high performance devices. These electronic transport metal oxides are generally processed at higher temperatures. In this research we report a room temperature processed WO3–x thin film as the electron transport layer for a high performance and low hysteresis device. The highly oxygen deficient WO3–x film was deposited at room temperature using e-beam evaporation in high vacuum conditions. For comparison, the amount of oxygen vacancies was reduced by postannealing of the as-deposited WO3–x films at 300 °C for 1 h in air. X-ray diffraction and Raman measurements showed no WO3–x characteristic peak of both the as-deposited and annealed films. From X-ray photoelectron spectroscopy and electron paramagnetic resonance, the as-deposited film shows large amounts of oxygen vacancies compared to the postannealed film. The bandgap of the postannealed film increases due to reduced conductivity and thus a reduction in the device performance, mainly because of the low Voc and high current–voltage hysteresis in the forward and reverse scans. The perovskite solar cell device developed using the room temperature deposited electron transport WO3–x layer has shown low current–voltage hysteresis. This device achieved a power conversion efficiency of 10.3% and hysteresis index of 2.1%. This work demonstrates the feasibility of the WO3–x film as an electron transport layer for the high efficiency perovskite solar cell with reduced hysteresis fabricated at low temperature using an industrially viable e-beam evaporation method.

Hydrogen activated WOx-supported catalysts for Lewis acid transformation to Bronsted acid observed by in situ DRIFTS of adsorbed ammonia: Effect of different supports on the Lewis acid transformation

The effect of hydrogen introduction on Lewis acid transformation to Bronsted acid was investigated over the WOx catalysts supported on different supports (HY-15, HY-500, MCM-22, SiO2, and Al2O3). The Lewis acid transformation on the catalysts was investigated by in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) of adsorbed NH3 at 100 °C under atmospheric pressure for 130 min. According to the results of in situ DRIFTS, ammonia migration from Lewis acid sites to Bronsted acid sites occurred over the WOx catalysts supported on all different supports. It is proposed that the partial reduction of WOx occurred under the hydrogen atmosphere, resulting in the generation of oxygen vacancies sites. The generated oxygen vacancies of the supported WOx catalysts were found to play an important role for activating the hydrogen spillover, leading to Lewis acid transformation to Bronsted acid. It was suggested that the selected support is the crucial factor for Lewis acid transformation performances. The results from our experiments showed that the weak interaction between WOx and support led to the easy reduction of W species, which promoted the generation of oxygen vacancies sites. The large amount of oxygen vacancies leads to high Lewis acid transformation. Moreover, the influence of different supports was discussed and investigated by several analytical techniques such as H2-TPD, H2-TPR, O2-TPD, UV–vis, XRD, XPS, and TEM-EDS techniques.

Heterogeneous Mo2C/Fe5C2 Nanoparticles Embedded in Nitrogen‐Doped Carbon as Efficient Electrocatalysts for the Oxygen Reduction Reaction

Searching for highly efficient non‐noble metal‐based catalysts for the oxygen reduction reaction (ORR) has received growing attention. Herein, we demonstrated a kind of hybrids of Mo2C/Fe5C2 embedded in N‐doped carbon (Mo2C/Fe5C2@NC) are prepared by pyrolyzing mixtures of Mo3O10‐EDA nanowires and biomass iron‐tannin‐framework ink (Fe‐TA). The as‐prepared Mo2C/Fe5C2@NC samples are characterized via X‐ray diffraction (XRD), scan electron microscope (SEM), transmission electron microscope (TEM), X‐ray photoelectronic spectrum (XPS) techniques. The systematic electrochemical study for the Mo2C/Fe5C2@NC shows a improved catalytic activity toward oxygen reduction reaction in O2 saturated 0.1 m KOH electrolyte. Specially, the Mo2C/Fe5C2@NC‐800 exhibits a remarkably high activity with an onset potentials of 0.92 V, half‐wave potential 0.78 V, and a small tafel slope of 76.89 mV dec–1, and also exhibits a larger limiting current density (5.2 mA cm–2 at 0.1 V vs. RHE), strong tolerance against methanol and long‐term stability (40000 s) comparable to those of the state‐of‐the‐art Pt/C catalysts. Such outstanding catalytic activities are originated from the intrinsic activity of Mo2C and the high conductivity provided by metallic Fe5C2 nanoparticles, and also due to the large amounts of oxygen vacancies created by Mo2C and Fe5C2 as electron donors in Mo2C/Fe5C2@NC hybrids. Therefore, this work is expected to boost the fabrication of various non‐noble carbide‐based heterostructure nanomaterials for practical applications in fuel cells and metal‐air batteries.

Exploration of Mn incorporated CeO2 nanoflakes with meso- and macropores for the effective simultaneous catalytic oxidation of carbon monoxide and propane

Highly porous ceria nanoflakes are prepared by a facile citric acid assisted sol–gel method. A Mn incorporated solid solution of CeO2 was also efficiently developed without disturbing the nanoflake morphology of pure CeO2. The formation of fluorite CeO2 with crystallite size ranging from 5–8 nm is evidently revealed from XRD analysis. The introduction of Mn to CeO2 resulted in the formation of smaller crystallites of CeO2 with reduced particle size and lattice parameters. SEM images displayed the flake like nature of CeO2 and Mn/CeO2 with meso and macro pores. TEM images confirm the pore size reduction of CeO2 with Mn doping which is already indicated from BET-BJH-surface area and pore-volume analysis. The presence of a large amount of oxygen vacancies in CeO2 upon Mn introduction is indicated from the drastic reduction in the peak intensities in the Raman spectrum. XPS results revealed that Ce exists in its +4 oxidation state whereas Mn exists in its +3 oxidation state, both of which are favorable for oxidation reactions. The catalytic performance of the prepared nanoflakes is investigated in the simultaneous oxidation of CO and C3H8. Mn incorporated CeO2 showed 100% oxidation of CO from 300 °C onwards and 84% hydrocarbon oxidation is observed even at a high gas flow rate of 500 ml/min at 400 °C over 0.5 g of the catalyst.

Novel Fenton-like catalyst γ-Cu-Al2O3-Bi12O15Cl6 with electron-poor Cu centre and electron-rich Bi centre for enhancement of phenolic compounds degradation and H2O2 utilization: The synergistic effects of σ-Cu-ligand, dual-reaction centres and oxygen vacancies

Novel Fenton-like catalyst γ-Cu-Al2O3-Bi12O15Cl6 with electron-poor Cu centre and electron-rich Bi centre was synthesized for selective degradation of phenolic compounds. Different from electron-rich Cu centre catalysts, the electron-poor Cu centre, which was induced by high electronegativity of Bi, could facilitate the formation of σ-Cu-ligand with phenolic compounds. On one hand, H2O2 could directly oxidize σ-Cu-ligand to HO-adduct radicals with the generation of OH. Meanwhile, Cu(II) in the σ-Cu(II) complexes could be reduced to Cu(I) by oxidization of the HO-adduct radicals to hydroxylation products. Such reaction not only prevented Cu(II) from oxidizing H2O2 to HO2/O2− but also enhanced the redox cycle of Cu(II)/Cu(I), which improved the catalytic activity and H2O2 utilization. On the other hand, although the σ-Cu-ligand was gradually decreased with the decrease of phenolic compounds, dual-reaction centre played the dominant role in catalytic reaction. In addition, large amounts of oxygen vacancies (OVs) are formed in Bi12O15Cl6 during the calcining process (BiOCl→Bi12O15Cl6), which can also increase the generation of OH. Thus, both electron-rich Bi center and OVs could still reduce H2O2 to ·OH for organics degradation even without the formation of σ-Cu-ligand. Being attributed to the synergistic effect of σ-Cu-ligand, dual-reaction centre and OVs mentioned above, γ-Cu-Al2O3-Bi12O15Cl6 achieved high catalytic activity for phenolic compounds degradation and utilization efficiency of H2O2 (η). In addition, various analytic methods (XPS, TPR, FT-IR, Raman, EPR and solid-state EPR) were used to prove the synergistic effect of the electron-poor/rich centre, σ-Cu-ligand and OVs of catalyst.

Catalytic removal NO by CO over LaNi0.5M0.5O3 (M = Co, Mn, Cu) perovskite oxide catalysts: Tune surface chemical composition to improve N2 selectivity

Catalytic removal of NO by CO has been studied over a series of LaNi0.5M0.5O3 (M = Co, Mn, Cu) perovskite oxide catalysts were synthetized via an improved sol–gel method. The effects of M-doped on physicochemical properties of LaNiO3 were systemic characterized by XRD, BET, SEM, ICP-AES, XPS, H2-TPR and O2-TPD techniques. The possible catalytic mechanism for NO + CO model reaction was also tentatively proposed with the help of the in situ DRIFTS technique. The M-doped samples remained pure perovskite structure and exhibited modified activity, among which the LaNi0.5Cu0.5O3 possessed optimized catalytic performance, especially superior N2 selectivity. It is confirmed that the amorphous CuO highly dispersed on Cu-doped defective perovskite oxide, the reduction of Cu2+ to Cu+ is vital for the chemisorption of CO, a large amount of oxygen vacancies accelerated the dissociation of NO and N2O. Hence, adsorbed CO can fast react with N and O at lower temperature, afterwards N2O was converted to N2 fleetly, leading the improvement of activity/selectivity toward NO + CO reaction.

Ultrafast methanol sensing properties of nano-spindle like In2O3 hierarchical structures with oxygen vacancies

Unique nano-spindle like In2O3 hierarchical structures have been successfully prepared using a simplified solvothermal method. The micromorphology and crystalline structure of the as-obtained are characterized by SEM, TEM, and XRD. Morphology analysis reveals that the nano-spindle like In2O3 hierarchical structures are composed of numerous ordered nanorods. The optical properties of the samples are also studied, and it is confirmed that the presence of a large amount of oxygen vacancies in the as-synthesized samples. The as-synthesized nano-spindle like In2O3 hierarchical structures are used for the detection of the methanol gas. The sensing properties of the as-manufactured sensor are carefully discussed and the sensor shows outstanding methanol sensing performance, especially ultrafast response time (<1 s). The sensing mechanism is also discussed. This work offers the possibility to manufacture low-cost, high-performance methanol sensor based on the as-synthesized nano-spindle like In2O3 hierarchical structures.

Controlled growth and characterization of In2O3 nanowires by chemical vapor deposition

The high-crystalline indium oxide (In2O3) nanowires were deposited by chemical vapor deposition (CVD) method on Si (111) substrates using C and In2O3 powders as the raw materials. The morphology, microstructures and the valences analysis of In2O3 nanowires were characterized by XRD, SEM, EDS, XPS and TEM techniques. The length and density of In2O3 nanowires can be effectively controlled by adjusting the experimental parameters. The optimal growth condition is obtained, namely the Au catalyst thickness of 12 nm, growth temperature of 1050 °C and Ar flow rate of 200 sccm. The cubic bixbyite structure as pure In2O3 (space group I a3¯) as well as large amounts of oxygen vacancies can be observed in the deposited In2O3 nanowires. The photoluminescence (PL) spectrum shows an ultraviolet emission peak located at 390.6 nm and two luminescence peaks located at 423.6 nm and 436.5 nm, which can be attributed to the near-band-edge emission and the presence of oxygen vacancy defects in the In2O3 nanowires, respectively.

Oxygen defect-rich WO3-x nanostructures with high photocatalytic activity for dehydration of isopropyl alcohol to propylene

In present study, two group of WO3-x nanocrystals (NCs) have been prepared via a facile solvothermal process and their photocatalytic activities for dehydration of isopropyl alcohol (IPA) to propylene (C3H6) under visible light irradiation have been studied. The photocatalysts are characterized by XRD, FSEM, HRTEM, XPS and UV–vis spectroscopic study. As for WO3-x NCs synthesized under different temperature, the highest photocatalytic efficiency was achieved for the W18O49 NCs prepared at 160 °C at C3H6 evolution rate of 145 μmol h−1 g−1. When it comes to the WO3-x NCs obtained using different solvents, the sea urchin-like W18O49 microspheres synthesized in ethanol has the greatest activity for photocatalytic dehydration of IPA. Their outstanding photocatalytic performances may stem from the large amount of oxygen vacancies (OVs) on their surfaces. The above results suggest the high potential of WO3-x NCs in application for C3H6 production.

Facile synthesis of PdO-doped Co3O4 nanoparticles as an efficient bifunctional oxygen electrocatalyst

The interfaces of multicomponent hybrid nanoparticles (MHNPs) have great effects on their electrocatalytic activities. Herein, a highly active multifunctional catalyst heterostructure PdO-doped Co3O4 (PdCo-300) nanoparticles with closely mutually connected interfaces were synthesized by a convenient strategy. The prepared PdCo-300 nanoparticles displayed high catalytic activities for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) in alkaline media. The results show that the considerable electrocatalytic activities and stabilities are associated with the formation of MHNPs with intimate connected boundary between PdO and Co3O4. At the interface, the decrease of Pd electron density (downshift of the d-band center) and the formation of large amount of oxygen vacancies in Co3O4 promoted the electrocatalytic performance. Theoretical calculations show that the synergy of Pd ions and Co ions at the interface can enhance the interaction between active oxygen species and the catalyst surface, resulting in the decrease of energy barrier for ORR.

Catalytic Performance of Gold Supported on Mn, Fe and Ni Doped Ceria in the Preferential Oxidation of CO in H2-Rich Stream

Ceria supported metal catalysts often exhibit high activity in the preferential oxidation (PROX) of CO in H2-rich stream and doping the ceria support with other metals proves to be rather effective in further enhancing their catalytic performance. Therefore, in this work, a series of ceria materials doped with Mn, Fe and Ni (CeM, where M = Mn, Fe and Ni; M/Ce = 1/8) were synthesized by a modified hydrothermal method; with the doped ceria materials (CeM) as the support, various supported gold catalysts (Au/CeM) were prepared by the colloidal deposition method. The influence of metal dopant on the performance of these ceria materials supported with gold catalysts in CO PROX was then investigated in detail with the help of various characterization measures such as N2 sorption, XRD, TEM, Raman spectroscopy, H2-TPR, XPS and XAS. The results indicate that the incorporation of Mn, Fe and Ni metal ions into ceria can remarkably increase the amount of oxygen vacancies in the doped ceria support, which is beneficial for enhancing the reducibility of ceria, the metal-support interaction and the dispersion of gold species. Although the gold catalysts supported on various doped ceria are similar in the size and state of Au nanoparticles, the CO conversions for CO PROX over Au/CeMn, Au/CeFe and Au/CeNi catalysts are 65.6%, 93.0% and 48.2%, respectively, much higher than the value of 33.6% over the undoped Au/CeO2 catalyst at ambient temperature. For CO PROX over the Au/CeNi catalyst, the conversion of CO remains near 100% at 60–130 °C, with a PROX selectivity to CO2 of higher than 50%. The excellent performance of Au/CeNi catalyst can be ascribed to its large amount of oxygen vacancies and high reducibility on account of Ni incorporation. The insight shown in this work helps to clarify the doping effect of other metals on the physicochemical properties of ceria, which is then beneficial to building a structure-performance relation for ceria supported gold catalyst as well as developing a better catalyst for removing trace CO in the hydrogen stream and producing high purity hydrogen.