Oxygen Vacancy Engineering Research Articles

Electrocatalytic conversion of nitrate to ammonia on the oxygen vacancy engineering of zinc oxide for nitrogen recovery from nitrate-polluted surface water.

Nitrate pollution in surface water poses a significant threat to drinking water safety. The integration of electrocatalytic reduction reaction of nitrate (NO3RR) to ammonia with ammonia collection processes offers a sustainable approach to nitrogen recovery from nitrate-polluted surface water. However, the low catalytic activity of existing catalysts has resulted in excessive energy consumption for NO3RR. Herein, we developed a facile approach of electrochemical reduction to generate oxygen vacancy (Ov) on zinc oxide nanoparticles (ZnO1-x NPs) to enhance catalytic activity. The ZnO1-x NPs achieved a high NH3-N selectivity of 92.4% and NH3-N production rate of 1007.9 h-1 m-2 at -0.65 V vs. RHE in 22.5 mg L-1, surpassing both pristine ZnO and the majority of catalysts reported in the literature. DFT calculations with in-situ Raman spectroscopy and ESR analysis revealed that the presence of Ov significantly increased the affinity for the (nitrate) and key intermediate of (nitrite). The strong adsorption of on Ov decreased the energy barrier of potential determining step ( →*NO3) from 0.49 to 0.1 eV, boosting the reaction rate. Furthermore, the strong adsorption of on Ov prevented its escape from the active sites, thereby minimizing by-product formation and enhancing ammonia selectivity. Moreover, the NO3RR, when coupled with a membrane separation process, achieved a 100% nitrogen recycling efficiency with low energy consumption of 0.55 kWh at a flow rate below 112 mL min-1 for the treatment of nitrate-polluted lake water. These results demonstrate that ZnO1-x NPs are a reliable catalytic material for NO₃RR, enabling the development of a sustainable technology for nitrogen recovery from nitrate-polluted surface water.

Enhanced energy storage performance of 0.85BaTiO3–0.15Bi(Mg0.5Hf0.5)O3 films via synergistic effect of defect dipole and oxygen vacancy engineering

Dielectric capacitors are widely used in electronic devices due to their ultra-fast charge/discharge rate and ultra-high power density, but their lower energy density and poor thermal stability limit their further application. In contrast to the traditional strategy of suppressing defects, this work combines oxygen vacancies with defect dipoles to improve the breakdown strength and polarization behavior of ferroelectric films. Low concentration of oxygen vacancies and defect dipoles can trap charge carriers and increase breakdown strength, but if the concentration is too high, it can easily make films prone to breakdown. Moreover, the defect dipoles can reduce Pr by providing intrinsic restoring force for polarization switching, while excessive defect dipoles and oxygen vacancies can pin domain walls and increase Pr. By delicately controlling the concentration of oxygen vacancies and defect dipoles in the film, the BT-BMH film deposited at 0.135 mbar achieved the maximum breakdown strength and slim P-E loops, inducing the energy density to reach 108.9 J·cm-3 with an efficiency of 79.6 % at room temperature and excellent thermal stability in the wide temperature range of -100∼350 °C with the energy density of 69.1 J·cm-3. This work reveals the important significance of reasonable defect control for improving energy storage performance and provides an effective method for developing high-performance dielectric capacitors.

Vacancy-Induced Symmetry Breaking in Titanium Dioxide Boosts the Photocatalytic Hydrogen Production from Methanol Aqueous Solution.

The key to optimizing photocatalysts lies in the efficient separation and oriented migration of the photogenerated carriers. Herein, we report that breaking continuous TiO6 tetragonal (D4h) symmetry in titanium dioxide material by oxygen vacancy engineering could induce a dipole field within the bulk phase and thus facilitate the separation and transfer of photogenerated electron-hole pairs. After further loading of Cu single-atom co-catalysts, the obtained catalyst attained a hydrogen (H2) yield rate of 15.84 mmol g-1 h-1 and a remarkable apparent quantum yield of 12.67% at 385 nm from methanol aqueous solution. This catalyst also demonstrated impressive stability for at least 24 h during the photocatalytic tests. The innovative concept of producing dipole fields in semiconductors by breaking the crystal symmetry offers a new perspective for designing photocatalysts.

Decorated-Induced Oxygen Vacancy Engineering for Ultra-Low Concentration Nonanal Sensing: A Case Study of La-Decorated Bi2O2CO3.

La-decorated Bi2O2CO3 (BCO-La) microspheres are synthesized using a facile wet chemical strategy for sensing low-concentration nonanal (C9H18O) at room temperature. These BCO-La gas sensors are applied to evaluate agricultural product quality, specifically for cooked rice. The sensitivity of the BCO-6La sensor significantly surpassed that of the pure BCO sensor, achieving a response value of 174.6 when detecting 30ppm nonanal gas. Notably, the BCO-6La sensor demonstrated a faster response time (36 s) when exposed to 18ppm of nonanal. Additionally, the selectivity toward nonanal gas detection is higher (approximately 4-24 times) compared to interfering gases (1-octanol, geranyl acetone, linalool, hexanal, 2-pentyfuran, and 1-octen-3-ol) during cooked rice quality detection. The gas sensing mechanism and the factors contributing to the enhanced sensing performance of the BCO-La microspheres are demonstrated through in situ FT-IR spectra and DFT analysis while the realistic detection scenario is carried out. In a broader context, the reported sensors here represent a novel platform for the detection and monitoring of gases released by agricultural products during storage.

Dual‐Carbon Assisted Oxygen Vacancy Engineering for Optimizing Mn(III) Sites to Enhance Zn–air Battery Performances

AbstractOwing to kinetic‐sluggish nature of electrocatalytic oxygen transformation processes, it is pivotal to develop durable and efficient bifunctional air electrode catalysts for fabricating high‐performance Zn–air batteries (ZABs). In this work, oxygen vacancy (Ov) induced Mn(III) sites optimization is achieved via nano‐micro structure modulation. Protonated carbon nitride (p‐C3N4) is applied as a structure‐stiffening module to immobilize α‐MnO2 on N/P‐doped active carbon (NPAC) and induce Ov construction. X‐ray adsorption spectra (XAS) disclose the formation of Ov and Mn(III) sites in MCC, the unit coordination structure is well maintained with the aid of a dual‐carbon strategy. Mn(III) sites efficiently catalyze oxygen reduction/evolution reaction (ORR/OER), MCC shows high half‐wave potential (E1/2) of 0.88 V for ORR and low potential at 10 mA cm−2 (Ej = 10) of 1.64 V for OER. According to density functional theory (DFT) simulations analysis, the gorgeous bifunctional activity is owing to that optimized charge distribution facilitates the intermediates transformation. Aqueous ZABs based on MCC manifests high peak power density of 452 mW cm−2 and durable cycling stability of 1640 h. Quasi‐solid‐state ZABs based on MCC also show satisfactory performances (175 mW cm−2, 105 h). This work provides the route to develop efficient and durable electrocatalyst for constructing ZABs with long lifespan and high‐power‐density.

High responsivity and detectivity β-Ga2O3 solar-blind photodetectors optimized by oxygen vacancy engineering

Solar-blind photodetectors (SBPDs) are core essential components for many critical applications such as precision guidance, fire warning, and space communications. Ultra-wide bandgap semiconductor β-Ga2O3 is considered to be an ideal material for the fabrication of SBPDs. However, synthetizing β-Ga2O3 with high quality factor while simultaneously in situ modulation of electronic and optoelectronic properties to enhance performance has been challenging. Here, pulsed laser deposition (PLD) technology is used to synthesize high-quality β-Ga2O3 thin films on a sapphire substrate. The oxygen vacancy engineered β-Ga2O3 films can achieve in situ precise control of their surface morphology, optical parameters, and optoelectronic properties by simply adjusting the oxygen pressure. Meanwhile, the optimal thickness of the β-Ga2O3 film for the developing high-performance SBPD is ∼221 nm, determined by fitting and analyzing the optical parameters measured by the ellipsometry. Subsequently, the influence of oxygen pressure on the performance of β-Ga2O3 SBPD is thoroughly explored, considering the optimization of electrode size and deposition time. When the oxygen pressure is set to 15 Pa, the β-Ga2O3-based SBPD achieves highly competitive responsivity (R) and detectivity (D*) at 250 nm, with values of 1080 A·W−1 and 1.4 × 1016 cm·W−1·Hz1/2, respectively. Additionally, the noise component of the β-Ga2O3 SBPD is further studied to calibrated the traditional device performance results. This work introduces a simple and straightforward approach to in situ tuning of the optoelectronic properties of β-Ga2O3, which is important for advancing β-Ga2O3 film growth technology and fabricating high-performance photodetectors.

Oxygen vacancies enhancing hierarchical NiCo2S4@MnO2 electrode for flexible asymmetric supercapacitors

The limited energy density of supercapacitors hampers their widespread application in electronic devices. Metal oxides, employed as electrode materials, suffer from low conductivity and stability, prompting extensive research in recent years to enhance their electrochemical properties. Among these efforts, the construction of core–shell heterostructures and the utilization of oxygen vacancy (VO) engineering have emerged as pivotal strategies for improving material stability and ion diffusion rates. Herein, core–shell composites comprising NiCo2S4 nanospheres and MnO2 nanosheets are grown in situ on carbon cloth (CC), forming nanoflower clusters while introducing VO defects through a chemical reduction method. Density functional theory (DFT) results proves that the existence of VO effectively enhances electronic and structural properties of MnO2, thereby enhancing capacitive properties. The electrochemical test results show that NiCo2S4@MnO2-V3 exhibits excellent 1376 F g−1 mass capacitance and 2.06 F cm−2 area capacitance at 1 A g−1. Moreover, NiCo2S4@MnO2-V3//activated carbon (AC) asymmetric supercapacitor (ASC) can achieve an energy density of 39.7 Wh kg−1 at a power density of 775 W kg−1, and maintains 15.5 Wh kg−1 even at 7749.77 W kg−1. Capacitance retention is 73.1 % after 10,000 cycles at 5 A g−1, and coulombic efficiency reaches 100 %, demonstrating satisfactory cycle stability. In addition, the device’s excellent flexibility offers broad application prospects in wearable electronic applications.

Oxygen Vacancy Engineering and Constructing Built-In Electric Field in Fe-g-C3N4/Bi2MoO6 Z-Scheme Heterojunction for Boosting Photo-Fenton Catalytic Degradation Performance of Tetracycline.

A novel Fe-g-C3N4/Bi2MoO6 (FCNB) Z-scheme heterojunction enriched with oxygen vacancy is constructed and employed for the photo-Fenton degradation of tetracycline (TC). The 2% FCNB demonstrates prominent catalytic performance and mineralization efficiency for TC wastewater, showing activity of 8.20 times greater than that of pure photocatalytic technology. Density-functional theory (DFT) calculations and degradation experiments confirm that the formation of Fe-N4 sites induces spin-polarization in the material, and the difference in Fermi energy levels results in the formation of built-in electric field at the contact interface, which facilitates the continuous generation and migration of photogenerated carriers to address the issue of insufficient cycling power of Fe (III)/Fe (II).The reactive radicals persistently target the extremely reactive sites anticipated by the Fukui function, causing the mineralization of TC molecules into "non-toxic" compounds through processes of hydroxylation, demethylation, and deamidation. This work holds significant importance in the domain of eliminating organic pollutants from water.

Construction and regulation of a perovskite-type sulfur reduction catalyst based on oxygen vacancy engineering for advanced lithium-sulfur batteries

Lithium-sulfur batteries are considered as a promising energy storage solution due to their considerably high theoretical capacity of 1675 mAh g−1 and high energy density of 2600 Wh kg−1. Nevertheless, the lithium-sulfur batteries in commercial application is facing some challenges such as the shuttle effect. In this paper, the perovskite-type La2Ti2O7-x with oxygen defect is developed and applied as an advanced catalyst in lithium-sulfur batteries. It is found that La2Ti2O7-x with oxygen defects can not only strengthen the chemical binding between the metal sites and LiPSs, but also provide additional adsorption and catalytic sites. The as-prepared La2Ti2O7-x/S cathodes exhibit a high initial discharge specific capacity of 1047 mAh g−1 at 1 C (1 C = 1675 mA g−1), and a capacity decay rate of merely 0.089 % per cycle after 500 cycles. Therefore, this study demonstrates a significant approach to producing high-performance lithium-sulfur batteries using perovskite transition metal oxides as high efficiency electrocatalyst.

Engineering Oxygen Vacancies of Co-Mn-Ni-Fe-Al High-Entropy Spinel Oxides by Adjusting Co Content for Enhanced Catalytic Combustion of Propane.

Transition metal-based oxides with similar oxidation activities for catalytic hydrocarbon combustion have attracted much attention. In this study, a new class of metal high-entropy oxides (CoxMnNiFeAl)3O4 (x = 1, 2, 3, 4, 5) with a porous structure was fabricated through a simple and inexpensive NaCl template-assisted sol-gel approach, which was employed for the catalytic oxidation of propane. The results indicated that the content of cobalt has a great impact on its activity, and the (Co4MnNiFeAl)3O4 catalyst exhibited the best catalytic activity. At the high space velocity of 60 000 mL·g-1·h-1, the optimized one with high-temperature treatment can still achieve 90% propane conversion at 309 °C, which is 68 and 178 °C lower than those of the (CoMnNiFeAl)3O4 catalyst and pure cobalt oxide, respectively. Meanwhile, it has the lowest apparent activation energy (46.6 KJ·mol-1) and the fastest reaction rate (26.976 × 10-6 mol·gcat-1·s-1 at 290 °C). The improved performance of the (Co4MnNiFeAl)3O4 catalyst could be attributed to the enhancement of low-temperature reducibility, the increased number of reactive surface oxygen species, and the cocktail effect of the high-entropy oxides. This work provides new insights into the preparation of efficient light alkane degradation catalysts and a realistic approach for the large-scale application of high-entropy oxides in the field of oxidation catalysts.

Accelerating ion diffusion kinetics with an intensified interfacial electric field for efficient hybrid capacitive deionization

The interfacial electric field (IEF) represents a cutting-edge strategy for enhancing ion diffusion kinetics, pivotal in various technological applications. Despite its extensive use, the mechanisms and strategies for regulating IEF remain underexplored. In this study, we enhanced the IEF in a MnO2-x/g-C3N4 (CN) heterostructure by engineering oxygen vacancies in MnO2, which increased the work function difference between MnO2 and CN. The increased work function difference effectively lowers the energy barrier for electron transfer at the heterostructure interface, thereby intensifying the IEF. The enhanced IEF subsequently provides a more potent driving force, facilitating ion movement within the electrode materials during the desalination process. The modified MnO2-x/CN heterostructure demonstrates a notable salt removal capacity of 45.5 mg g−1 and an impressive salt removal rate of 4 mg g−1 min−1, under an operational voltage of 1.2 V in a 500 mg/L NaCl solution. This research not only deepens our understanding of IEF modulation in materials but also sets the stage for the development of high-performance electrodes for hybrid capacitive deionization systems.

Kinetics‐Matched Electrode Design for Zn‐Metal Free Zinc Ion Batteries with High Energy Density and Stabilities

AbstractThe metal‐free rocking chair type Zn‐ion batteries (ZIBs) provide a promising approach toward the promotion of the Zn‐based batteries by circumventing the challenges including dendrite growth, hydrogen evolution reaction (HER), and surface corrosion. In order to sufficiently exploit the available capacity of this metal‐free batteries, it is necessary to effectively enhance the sluggish reaction kinetics of divalent zinc ions. Equally important is to achieve a balance in the kinetics between cathode and anode. Here, hetero‐valent doping and oxygen vacancy engineering are employed to effectively enhance the reaction dynamics of V2O5 cathodes and MoO3 anodes. Moreover, to the best of the knowledge, for the first time, the strategy of kinetics matching between the two electrodes is applied to the construction of rocking‐chair zinc ion batteries, enabling the cathode and anode to share similar zinc ion migration rates, and achieving a high energy density of up to 58.7 Wh kg−1 (based on the total electrode mass) as well as excellent cycling stability (90% after 500 cycles). This work demonstrates the importance of kinetics matching in zinc‐ion full‐cell performance and pave a benefitable avenue to for the pursuit of advanced multi‐valent metal‐ion batteries.

Oxygen vacancy engineering in ZnO/ZrO2 composite catalysts for highly enhanced hydrogen production by methanol steam reforming

The ZnO/ZrO2 binary catalyst system has been an emerging and promising catalyst for efficient production of H2 through methanol steam reforming (MSR). Herein, ZrO2 supports with different crystalline phases were prepared by the oxygen vacancy engineering strategy of Li doping, and then ZnO/ZrO2 catalysts were prepared by the isovolumic impregnation method. The different quantities of doped Li have been found to have a significant impact on dominant crystal phase of ZrO2 supports, which dictates the interaction between ZnO and ZrO2 and the number of oxygen vacancies. In comparison with ZnO/ZrO2-20Li and ZnO/ZrO2-40Li catalysts with predominate tetragonal and monoclinic crystal phase, ZnO/ZrO2-3Li with a mixed crystalline phase exhibits higher catalytic activity for methanol conversion (XCH3OH) and CO selectivity (SCO). Complete methanol conversion of the best performing ZnO/ZrO2-3Li catalyst was observed at a very low CO selectivity of 3.1 % at 375 ℃. The XRD, UV, and XPS characterization results indicate that the strong interaction between ZrO2 and ZnO leads to the appearance of large amount of oxygen vacancies at the ZnO/ZrO2 interface, which greatly improves the performance of the catalyst. ZnO/ZrO2 catalyst showed remarkable stability without obvious deactivation after 32 hours of continuous testing. This work highlights the effectiveness of oxygen vacancy engineering of the ZnO/ZrO2 catalysts for applications in methanol steam reforming and other heterogeneous catalytic systems.

Oxygen vacancy engineering in Si-doped, HfO2 ferroelectric capacitors using Ti oxygen scavenging layers

In this paper, the ferroelectric properties of TiN/Ti/Si:HfO2/TiN stacks are shown to be modulated by the Ti oxygen scavenging layer, leading to improved remanent polarization and wake-up at low switching fields. Hard x-ray photoelectron spectroscopy is used to measure the oxygen vacancy (VO) concentration in Si-doped HfO2 based capacitors. This VO engineered ferroelectric stack is then assessed at the wafer scale within 16 kbit 1T-1C FeRAM arrays integrated into 130 nm CMOS. The introduction of a Ti oxygen scavenging layer at the top interface of Si:HfO2-based BEOL-integrated metal/ferroelectric/metal capacitors enhances their ferroelectric (FE) behavior (+100% remanent polarization 2.Pr), confirming the positive role of modest concentrations of VO in orthorhombic phase crystallization at low thermal budgets. It is statistically demonstrated at 16 kbit array level that VO-rich FE Si:HfO2 facilitates 2.5 V FeRAM array operation with improved memory window. The field cycling dependence of the memory window is correlated with the VO concentration, and an endurance of 108 cycles is measured at the array level.

Controllable preparation of Co-based catalysts doped with Cu and Mo for boosting hydrogen evolution

Hydrogen evolution from ammonia borane hydrolysis is a promising way for utilization of clean energy. Development of efficient and stable non-noble catalysts for improvement of hydrogen generation rate is essential but still a challenge. Herein, the heterostructured Co-based catalysts were controllably designed by combining the synergistic effect with oxygen vacancy engineering to improve the hydrogen generation rate. CoCu1Mo3-NC-O-15 exhibits the TOF value of 24.44 min−1 at 298 K with addition of 0.44 M NaOH, which is nearly 68 times that of Co-NC. The activation energy over CoCu1Mo3-NC-O-15 is 28.44 kJ mol−1. The CoCu1Mo3-NC-O-15 catalyst presents the good stability in ammonia borane hydrolysis reaction due to the carbon-coated structure. The strong synergistic effect and oxygen vacancy are favorable to the adsorption and dissociation of NH3BH3 and H2O molecules, leading to an astonishing improvement of catalytic activity. This study provides a novel way to design the heterostructured catalysts and a rational way to boost the dehydrogenation rate from AB.

Tailoring oxygen vacancies by synergy of dual metal cations in LaCo0.8M0.2O3 (M = Cu, Ni, Fe, Mn) towards catalytic oxidation of toluene

Enhancing the catalytic performance of transition metal oxide catalysts is prerequisite for the efficient catalytic oxidation of VOCs. Here the B-site partially substituted LaCoO3 (LaCo0.8M0.2O3, M = Cu, Ni, Fe and Mn) catalysts was synthesized for the catalytic oxidation of toluene. Among these catalysts, LaCo0.8Ni0.2O3 catalyst exhibits remarkable catalytic performance for toluene with T50 = 226 °C and T90 = 239 °C at an initial toluene concentration of 1000 ppm, whose T50 (and T90) reduced by 13 °C (and 34 °C) compared with that of LaCoO3. Confirmed by BET, XPS, and EPR characterizations, Ni substitution improves the specific surface area, Co3+/Co2+ ratio, Oads/Olatt ratio, and oxygen vacancies concentration. This improvement indicates the improvement of adsorption and activation of reactant, mobility of oxygen species, thereby contributing to the superior catalytic performance in toluene oxidation. The B-site of LaCoO3 occupied by dual cations caused the lattice distortion and formation of oxygen vacancies due to the ionic radii difference between Co and Ni cations. Moreover, the apparent activation energy of LaCo0.8Ni0.2O3, as the determining factor for the catalytic oxidation rate, was remarkably reduced. Our findings confirmed the synergy effect of Co and Ni cations at B-site on the enhancement of catalytic activity, which provides a promising strategy for oxygen vacancy engineering.

Interfacial oxygen vacancy engineering of double Z-scheme heterojunction Bi2MoO6/MnWO4/g-C3N4 for efficient photocatalytic degradation of iodohydrin

The synthesis of a dual Z-scheme heterojunction, Bi2MoO6/MnWO4/g-C3N4 (BMCM-x), enriched with oxygen voids, has been synthesized by an in-situ generation method. The ideal composite specimen, BMCM-50, managed to break down over 85 % of Iohexol in a span of 40 min. The emergence of oxygen voids serves to inhibit the merging of photogenerated carriers and fosters the creation of reactive radicals. The dual Z-scheme heterojunction is capable of isolating photogenerated carriers and enhancing redox capacity, markedly boosting BMCM-50’s photocatalytic breakdown efficiency.

The Surface/Interface Modulation of Platinum Group Metal (PGM)-Free Catalysts for VOCs and CO Catalytic Oxidation.

Effective management of volatile organic compounds (VOCs) and carbon monoxide (CO) is critical to human health and the ecological environment. Catalytic oxidation is one of the most promising technologies for achieving efficient VOCs and CO emission control. Platinum group metal (PGM)-free catalysts are recently receiving sustainable attention in catalyzing VOCs and CO removal due to their low cost, superior catalytic activity, and excellent stability, but PGM-free catalysts face challenges in low-temperature catalytic efficiency. In this mini-review, starting with discussing the catalytic mechanism of VOCs and CO oxidation, we summarize the surface/interface modulation strategies of PGM-free catalysts to promote oxygen and VOCs/CO molecule activation for enhanced low-temperature oxidation activity, including oxygen vacancy engineering, heteroatom doping, surface acidity modification, and active interface construction. We highlight the currently remaining challenges and prospects of advanced PGM-free catalyst development for highly efficient VOCs and CO emission control in practical applications.

Oxygen vacancy-mediated Mn2O3 catalyst with high efficiency and stability for toluene oxidation

Oxygen vacancy engineering in transition metal oxides is an effective strategy for improving catalytic performance. Herein, defect-enriched Mn2O3 catalysts were constructed by controlling the calcination temperature. The high content of oxygen vacancies and accompanying Mn4+ ions were generated in Mn2O3 catalysts calcined at low temperature, which could greatly improve the low-temperature reducibility and migration of surface oxygen species. DFT theoretical calculations further confirmed that molecular oxygen and toluene were easily adsorbed over defective α-Mn2O3 (222) facets with an energy of −0.29 and −0.48 eV, respectively, and corresponding OO bond length is stretched to 1.43 Å, resulting in the highly reactive oxygen species. Mn2O3-300 catalyst with abundant oxygen vacancies exhibited the highest specific reaction rate and lowest activation energy. Furthermore, the optimized catalyst possessed the outstanding stability, water tolerance and CO2 yield. In comparison with the fresh Mn2O3-300 catalyst, the physical structure and surface property of the used catalyst remained almost unchanged regardless of whether undergoing the stability test at consecutive catalytic runs as well as high temperature, and water resistance test. In situ DRIFTS spectra further elucidated that introducing the water vapor had little effect on the reaction intermediates, indicating the excellent durability of the defect-enriched catalyst.

Constructing Adsorption Site-Enhanced Vo-BiOCl/rGO Heterostructures for Efficient Response to NO2/NH3 Gases at Room Temperature.

Real-time detection of harmful gases at room temperature has become a serious problem in public health and environmental monitoring. Two-dimensional materials with semiconductor properties BiOCl is a promising gas-sensitive material due to its large specific surface area and adjustable band gap as well as outstanding safety characteristics. However, limited by the weak gas adsorption sites and sluggish charge-transfer ability, the performance of BiOCl could not be fully exploited. Oxygen vacancy (Vo) engineering can introduce lattice defects, thereby significantly increasing the local charge density and enhancing the adsorption of gases, which is an effective strategy to enhance the gas-sensing performance. In this work, we composite BiOCl with a vacancy (Vo-BiOCl) and reduced graphene oxide (rGO) to construct a Vo-BiOCl/rGO heterostructure with enhanced gas adsorption sites. Experimental and theoretical calculations show that Vo can enhance the adsorption of gases and the introduction of rGO forms a high-quality heterostructure with BiOCl, which can effectively reduce the band gap of BiOCl and promote electron transfer, thereby improving the sensitivity of the sensor. Benefiting from above, Vo-BiOCl/rGO achieves the ability to detect low concentrations of NO2/NH3 at room temperature, with high sensitivity (55% at 1 ppm of NO2 and -28% at 1 ppm of NH3), fast response time (40 s at 1 ppm of NO2 and 2 s at 1 ppm of NH3), good stability (over 150 days), and fully recoverable gas sensitivity.