SCIENCE CHINA Materials, Volume 63 , Issue 11 : 2089-2118(2020) https://doi.org/10.1007/s40843-020-1305-6

Oxygen vacancies in metal oxides: recent progress towards advanced catalyst design

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  • ReceivedJan 20, 2020
  • AcceptedMar 17, 2020
  • PublishedMay 19, 2020


Funded by

the National Natural Science Foundation of China(U1905215,51772053,51672046)


This work was financially supported by the National Natural Science Foundation of China (U1905215, 51772053 and 51672046).

Interest statement

The authors declare no conflict of interest.

Contributions statement

Zhuang Z and Yu Y conceptualized the work, and wrote and revised the manuscript. Zhuang G and Chen Y collected and summarized the literatures, and contributed to the manuscript writing. Yu J revised the manuscript and offered creative proposal for improving the depth and coverage of the review. All authors contributed to the general discussion.

Author information

Guoxin Zhuang received his BSc in materials science and engineering from Fuzhou University. He is currently pursuing his PhD degree at Fuzhou University under the supervision of Prof. Yu and Prof. Zhuang. His research focuses on the design of MOFs and catalysts for CO2 photoreduction.

Zanyong Zhuang received his BSc in chemistry from Xiamen University, and his PhD in 2011 from Fujian Institute of Research on the Structure of Matter (FJIRSM), Chinese Academy of Sciences (CAS). He became an associate researcher in FJIRSM, CAS in 2014. Currently he is an associate professor at Fuzhou University. His research interests include the design of low-dimensional nanostructures, nanocrystals growth and assembly, comprehensive utilization of solid waste, and the related catalytic topics.

Yan Yu received her BSc, MSc and PhD degrees from Fuzhou University. She was a postdoctoral fellow in FJIRSM, CAS, and became a Professor at Fuzhou University in 2011. Her research interests include semiconductors, photocatalysis, environmental purification materials, comprehensive utilization of solid waste, and the related topics.

Jiaguo Yu received his BSc and MSc degrees in chemistry from the Central China Normal University and Xi’an Jiaotong University, respectively, and his PhD in materials science in 2000 from Wuhan University of Technology. In 2000, he became a Professor at Wuhan University of Technology. He was a postdoctoral fellow at the Chinese University of Hong Kong from 2001 to 2004, a visiting scientist from 2005 to 2006 at the University of Bristol, and a visiting scholar from 2007 to 2008 at the University of Texas, Austin. His research interests include semiconductors, photocatalysis, photocatalytic hydrogen production, solar fuels, dye-sensitized solar cells, adsorption, CO2 capture, graphene, and the related topics.


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  • Figure 1

    Polyhedral representation of a pristine TiO6 octahedron and a defective octahedron with OV resulting from Cu doping at a Ti site. Adapted with permission from Ref. [60], Copyright 2019, WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  • Figure 2

    (a) Schematic of high-energy proton irradiation on oxide-semiconductor thin-film transistors (α-ZTO, α-IGZO, and ZnO); the O 1s spectra from X-ray photoelectron spectroscopy (XPS) analysis are given for (b) ZnO, (c) α-IGZO, (d) α-ZTO (2:1), and (e) α-ZTO (4:1) before and after various doses of proton irradiation. Adapted with permission from Ref. [63], Copyright 2018, WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  • Figure 3

    Schematic and structure of SnO2−x/In2O3−y prepared from UHV (solid) and furnace annealing (dotted) system, with O atom in blue. Adapted with permission from Ref. [96], Copyright 2018, Elsevier.

  • Figure 4

    Calculated reaction energy diagram of NH3 treatment over the WO3 (001) plane, along with mass spectrometer signals (online MS signals) of N2, NO, H2O, and N2O generated from the temperature-programmed reaction of WO3 with NH3. Adapted with permission from Ref. [101], Copyright 2019, Elsevier.

  • Figure 5

    (a) Schematic illustration of the fabrication process of OVs-OM LSCO; (b) O 1s and (c) Co 2p XPS spectra of OVs-OM LSCO and OM LSCO; low-temperature EPR spectra of OVs-OM LSCO and OM LSCO (d) in high vacuum and (e) in air. Adapted with permission from Ref. [116], Copyright 2019, American Chemical Society.

  • Figure 6

    Theoretical calculations of the most stable structures and EV of CeO2 (110) doped with one single Cu site with (a) 1 OV; (b) 2 OVs; and (c) 3 OVs. Adapted with permission from Ref. [133], Copyright 2018, American Chemical Society.

  • Figure 7

    Creating OVs by the partial replacement of O by S via anion doping after gaseous sulfur treatment of Li1.2Ni0.13Co0.13Mn0.54O2 (LNCMO). Adapted with permission from Ref. [141], Copyright 2019, Elsevier.

  • Figure 8

    (a) Illustration of the fabrication process of CeO2/Co3O4 hybrid nanostructure; (b) model and charge-density difference of the CeO2(111)/Co3O4(110) interface; (c) Ce 3d XPS of CeO2 and CeO2/Co3O4; (d) O 1s and (e) Co 2p XPS spectra of Co3O4 and CeO2/Co3O4; (f) Co L-edge X-ray absorption near-edge structure (XANES) of Co3O4 and CeO2/Co3O4. Adapted with permission from Ref. [149], Copyright 2019, American Chemical Society.

  • Figure 9

    EV for LaBO3 (LB) and La1−xSrxBO3 (LSB) of varying compositions as a function of the linear combination of (a) calculated and (b) experimental band gap energy (ΔE) and formation enthalpy (ΔHf, oxide) of the oxide. Adapted with permission from Ref. [61], Copyright 2014, The Royal Society of Chemistry.

  • Figure 10

    (a) Structural model of different MnO2 phases; (b) the relationship between reactivity and EV of different MnO2 phases. Adapted with permission from Ref. [158], Copyright 2019, American Chemical Society.

  • Figure 11

    (a) The path and energy barriers (Ea) for oxygen ion movement in brownmillerite phase SrCoOx through OVs channels when the oxide undergoes a topotactic oxidation to form perovskite phase SrCoOx; (b) as an oxygen ion moves from one intercalation site to another along the [010] direction of the OVs channel, the Ea increases as the strain rate tends from +2% to −2%, where higher Ea is more difficult for OVs to form; (c) a summary of the intercalation enthalpy (Hi) and the activation energy (ΔEa) as a function of strain. Adapted with permission from Ref. [178], Copyright 2016, WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  • Figure 12

    (a) UV-vis DRS of TiO2 treated by air (Air-500) and H2 (H2-500) to determine the optical band gaps, with the corresponding Tauc plots in the inset; (b) XPS valence band spectra and (c) energy band diagrams of the Air-500 and H2-500 TiO2. Adapted with permission from Ref. [226], Copyright 2018, Elsevier; calculated density of states (DOS) and partial charge density around the VB of (d) ZnO and (e) ZnO with an OV (gray, Zn; red, O; white, H atoms; yellow regions, charge density contour). Adapted with permission from Ref. [227], Copyright 2018, Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim; (f) the density of electronic states for OVs-free ZnO (p-ZnO) and m-ZnO; (g) XPS valence band spectra of p-ZnO and m-ZnO; the inset shows the zoomed valence band spectra. Adapted with permission from Ref. [228], Copyright 2013, The Royal Society of Chemistry; (h) the OVs induce n-type doping mechanism under illumination. Adapted with permission from Ref. [229], Copyright 2019, Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim; (i) mechanism of plasmonic photocatalysis on Bi/BiOCl. Adapted with permission from Ref. [230], Copyright 2017, Elsevier.

  • Figure 13

    (a) Crystal structure of Sr2Bi2Nb2TiO12 nanosheets (SBNT-HR) without OVs; (b) TEM image and (c) SAED pattern of SBNT-HR-0.5 (SBNT-HR treated with 0.5 mL glyoxal to create OVs); (d) HRTEM image of SBNT-HR; (e) HRTEM image of SBNT-HR-0.5; the OVs concentration of the bulk (SBNT-SSR), the perfect nanosheets (SBNT-HR), and the defective nanosheets (SBNT-HR-X, X denoting the amount of glyoxal used to treat SBNT-HR to create OVs, X = 0.3, 0.5, and 1 mL) are determined by (f) UV-vis DRS (band gap shown in inset), (g) EPR, (h) Nd 3d, Ti 2p, and (i) O 1s XPS. Adapted with permission from Ref. [232], Copyright 2019, Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  • Figure 14

    (a) Energy diagram of In2O3−n with different amounts of OVs; (b) schematic illustration of how excess OVs affect the transfer of photoelectron in photon-to-electron conversion processes; (c) plot of the best IPCE efficiency with visible light (>400 nm) of In2O3 obtained by calcination in air at 250, 350, 450°C, as a function of the relative OV amount. Adapted with permission from Ref. [251], Copyright 2013, American Association for the Advancement of Science (AAAS); (d) the charge density of MnO2(110) varying with the number of OVs; (e) structural model and total charge density of β-MnO2 (110) with 0, 4, 8, 12, and 16 OVs, respectively. Adapted with permission from Ref. [252], Copyright 2015, American Chemical Society.

  • Figure 15

    Different adsorption configurations of CO2 on the anatase (001) surface (a) without and (c) with different OVs, in side view and top view (upper and lower panels, respectively). Ti = blue, OTiO2 = red, OCO2 = red with yellow plus sign, C = brown. B(I) is a strong chemisorbed monodentate carbonate configuration, and L(I), L(II), and L(III) are physisorbed configurations; (b) different OVs on an anatase (001) TiO2 surface (Ti = gray, O = red, OV = yellow.). Adapted with permission from Ref. [274], Copyright 2016, American Chemical Society.

  • Figure 16

    The optimized geometries (side view) and free energy changes (in eV) of *N2 on pristine and OV-containing TiO2. Cyan, red, and blue spheres indicate Ti, O, and N atoms, respectively. Adapted with permission from Ref. [277], Copyright 2019, Elsevier.

  • Figure 17

    (a) Calculated band structures and DOS of Bi2MoO6-OVs, and adsorption of CO2 on (b) OVs-rich and (c) OV-free Bi2MoO6. The yellow and blue iso-surfaces represent the charge accumulation and depletion in the space. Adapted with permission from Ref. [267], Copyright 2019, Elsevier.

  • Figure 18

    Theoretical study of water adsorption on the defect-free BiOCl (a) (100) and (e) (010) surfaces; theoretical study of water adsorption on the BiOCl (b) (100) and (f) (010) surfaces with an OV; the corresponding charge density difference is given in (c) and (g) for the BiOCl (100) and (010) surfaces respectively; PDOS of H2O on the (d) (100) and (h) (010) surface of BiOCl with different adsorption structures (HBs: hydrogen bond; ΔE: the water adsorption energy; Δρ: the Bader charge change of the adsorbed water). Adapted with permission from Ref. [280], Copyright 2016, American Chemical Society.

  • Figure 19

    (a) The free energy diagram for different NRR pathways on OVs-rich MoO2. In the distal pathway (blue dash line), the protonation of NNH* to HNNH* has an energy barrier of ΔG = 0.69 eV, and deprotonation of N2H2* to form N* species has ΔG = 0.54 eV. However, the energy barrier is effectively decreased in the distal/alternative hybrid path to ΔG = 0.36 eV; (b) energy profiles for electrocatalytic N2 reduction on the surfaces of MoO2 with no OV, rich OVs, and excessive OVs. Adapted with permission from Ref. [212], Copyright 2019, Elsevier.

  • Figure 20

    Calculated free energy (in eV) diagrams for the electrochemical reduction of CO2 to formate on (a) Co3O4 with OVs and (b) intact Co3O4 single unit cell layers. The first step is an electron transfer to form CO2•− and the second step involves a simultaneous proton/electron transfer, the product of which gives formic acid. Asterisk denotes the active site. The spheres in white, red, grey, and light blue represent H, O, C, and Co atoms, respectively. Adapted with permission from Ref. [288], Copyright 2017, Nature Publishing Group.

  • Figure 21

    Mechanisms for the photoreduction of CO2 with H2O vapor over highly dispersed Pt nanoparticles on ultrathin TiO2 support Adapted with permission from ref. [295], Copyright 2018, Elsevier.

  • Figure 22

    Most stable adsorption geometries and adsorption energies of bent CO2 on (S1) a stoichiometric TiO2 surface, (S2) a stoichiometric TiO2 surface with a Cu atom, (R1) a reduced TiO2 surface with OV, (R2) a reduced TiO2 surface with a Cu atom in an OV, (R3) a reduced TiO2 surface with Cu near an OV, and (R4) a reduced TiO2 surface with Cu far from OV. Adapted with permission from Ref. [296], Copyright 2018, American Chemical Society.

  • Figure 23

    (a) CO2 reduction on Cu/CeO2x heterodimers (HDs) for methane evolution at the active sites on the interface; (b) thermodynamics of methane and methanol evolution at 0 and −1.2VRHE; (c, d) scaling relationship of CO*/CHO* and H2CO*/OH* is broken due to a unique bidentate adsorption. Adapted with permission from Ref. [259], Copyright 2019, American Chemical Society.

  • Figure 24

    (a) The chemical shift of Ti 2p3/2 for TiO2-A, TiO2-350, TiO2-550, and TiO2-750; (b) the transient photocurrent responses of TiO2-A, TiO2-350, TiO2-550, and TiO2-750 vs. SCE under UV-vis irradiation; (c) Ti 2p3/2 and O 1s XPS spectra of TiO2-350 and TiO2-550; (d) simulated geometric structures of TiO2 with junction of O vacancies and Ti vacancies; (e) charge density difference between normal TiO2 and TiO2 with junction of OVs and Ti vacancies. Adapted with permission from Ref. [297], Copyright 2018, WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  • Table 1   Reaction energy (in eV) of OV creation on the In2O3 (110) surface in different sites (D1, D2, D3, D4, D5 and D6) by thermal desorption and by reduction. Adapted with permission from Ref. [59], Copyright 2013, American Chemical Society.

    Reaction equation








    a p-In2O3(110) → OV-In2O3x(110) + ½ O2







    b p-In2O3(110) + H2 → OV-In2O3x(110) + H2O







    c p-In2O3(110) + CO → OV-In2O3−x(110) + CO2







  • Table 2   EV for different crystal planes of β-MnO2. Adapted with permission from Ref. [166], Copyright 2014, American Chemical Society.

    Miller index

    EV (eV)















  • Table 3   Advantages and shortcomings of developed synthetic strategies for OVs

    Synthetic strategy


    Required atmosphere or reagent


    Structural damage

    High-energy particlebombardment







    Thermal treatment








    Chemical reduction


    H2/NH3/reducing regents



    Slightly, but may incurphase transformation

    Ion doping



    Type of dopant ion

    Concentration of dopant ion

    Introduce dopant, and may incur phase transformation

    Interfacial engineering


    Not required

    Type of noble metal

    Type of transition metal oxides


    New hybrid structure