Introduction Of Oxygen Vacancies Research Articles

Engineering Oxygen Vacancies in In2O3 with Enhanced Polysulfides Immobilization and Selective Catalytic Capability.

Lithium-sulfur (Li-S) battery is identified as an ideal candidate for next-generation energy storage systems in consideration of its high theoretical energy density and abundant sulfur resources. However, the shuttling behavior of soluble polysulfides (LiPSs) and their sluggish reaction kinetics severely limit the practical application of the current Li-S battery. In this work, a series of In2O3 nanocubes with different oxygen vacancy concentrations are designed and prepared via a facile self-template method. The introduced oxygen vacancy on In2O3 can effectively rearrange the charge distribution and enhance sulfiphilic property. Moreover, the In2O3 with high oxygen vacancy concentration (H-In2O3) can slightly slow down the solid-liquid conversion process and significantly accelerate the liquid-solid conversion process, thus reducing the accumulation of LiPSs in electrolyte and inhibiting the shuttle effect. Contributed by the unique selective catalytic capability, the prepared H-In2O3 exhibits excellent electrochemical performance when used as sulfur host. For instance, a high reversible capacity of 609 mAh g-1 is obtained with only 0.044% capacity decay per cycle over 1000 cycles at 1.0C. This work presents a typical example for designing advanced sulfur hosts, which is crucial for the commercialization of Li-S battery.

Understanding of mercury/oxygen reaction mechanism over BiOBr photocatalyst with oxygen vacancy

BiOBr with the advantage of easily generated surface oxygen vacancy, has been considered as a promising photocatalyst for Hg0 oxidation in the flue gas and the active oxygen species is crucial for the oxidation reaction. Nevertheless, the detailed mercury/oxygen reaction mechanism on the BiOBr surface is still unclear and the effect of oxygen vacancy on the reaction process was worth in-depth study. Herein, the oxygen-involved Hg0 oxidation mechanism on the BiOBr surface and the effect of oxygen vacancy were deeply understood by quantum chemistry calculation. The reactivity difference of chemisorbed and lattice oxygen species was revealed. Therein, the chemisorbed oxygen derived from the activation of gaseous O2 molecule showed the higher reactivity than lattice oxygen for Hg0 oxidation reaction. The introduction of oxygen vacancy could promote O2 activation and simultaneously reduce the energy barrier of HgO formation from 1.76 to 1.45 eV. In addition, the energy barrier of oxygen vacancy recovery (0.05 eV) was higher than that of O2 activation (0.02 eV), indicating that the initial oxygen vacancy could be retained in the reaction process. This work deeply revealed the mercury/oxygen reaction mechanism over BiOBr photocatalyst and provided the guidance for the catalyst design in the photocatalytic Hg0 oxidation.

Doping Engineering To Modulate Surface Plasmon Resonance and Enzyme-like Activities for Enhancing Photoacoustic Imaging-Guided Targeted Cancer Therapy in the Second Near-Infrared Window.

Biological imaging-guided targeted tumor therapy has been a soughtafter goal in the field of cancer diagnosis and treatment. To this end, we proposed a strategy to modulate surface plasmon resonance and endow WO3-x nanoparticles (NPs) with enzyme-like catalytic properties by doping Fe2+ in the structure of the NPs. Doping of the Fe2+ introduced oxygen vacancies into the structure of the NPs, inducing a red shift of the maximum absorption wavelength into the near-infrared II (NIR-II) region and enhancing the photoacoustic (PA) and photothermal properties of the NPs for more effective imaging-guided cancer therapy. Under NIR-II laser irradiation, the Fe-WO3-x NPs produced very strong NIR-II PA and photothermal effects, which significantly enhanced the PA imaging and photothermal treatment effects. On the other hand, Fe2+ in Fe-WO3-x could undergo Fenton reactions with H2O2 in the tumor tissue to generate ·OH for chemodynamic therapy. In addition, Fe-WO3-x can also catalyze the above reactions to produce more reactive oxygen species (ROS) and induce the oxidation of NADH to interfere with intracellular adenosine triphosphate (ATP) synthesis, thereby further improving the efficiency of cancer therapy. Specific imaging of tumor tissue and targeted synergistic therapy was achieved after ligation of a MUC1 aptamer to the surface of the Fe-WO3-x NPs by the complexing of -COOH in MUC1 with tungsten ions on the surface of the NPs. These results demonstrated that Fe-WO3-x NPs could be a promising diagnosis and therapeutic agent for cancer. Such a study opens up new avenues into the rational design of nanodiagnosis and treatment agents for NIR-II PA imaging and cancer therapy.

Design of atomically dispersed N-Bi(3+x)+--OV sites in ultrathin Bi2O2CO3 nanosheets for efficient and durable visible-light-driven CO2 reduction

The introduction of oxygen vacancies (OVs) into photocatalysts has proven to be a successful tactic to boost CO2 reduction. However, the challenge lies in acquiring OV sites that are stable in the long term, highly dispersed, and tunable in concentration. Herein, an innovative configuration, referred to as N-Bi(3+x)+--OV, was developed for the model semiconductor Bi2O2CO3 via an in situ anion doping approach. The structure enables the synthetic photocatalyst to exhibit superb CO2 photoreduction performance, with approximately 100% CO selectivity and remarkable long-term stability. Experimental studies and density functional theory (DFT) calculations show that replacing O2- with N3- uniformly in the [Bi2O2]2+ structural unit increases the chemical valence of Bi, elongates nearby Bi─O bonds, releases lattice O, improves CO2 absorption, and decreases the energy barrier for the formation of the critical intermediate *COOH. This study offers new insights and potential opportunities for the development of reliable defect-type semiconductors and their catalytic applications.

Oxygen vacancies-promoted removal of COS via catalytic hydrolysis over CuTiO2-δ nanoflowers

Catalytic hydrolysis was considered as an efficient technology to remove carbonyl sulfide (COS). The introduction of oxygen vacancy (Ov) is a promising strategy to improve the catalytic performance of COS hydrolysis by promoting the adsorption and activation of reactants. Herein, we reported a Cu-doped TiO2 nanoflower with abundant oxygen vacancies for COS hydrolysis. The Cu species successfully entered the crystal lattice of TiO2 and induced more oxygen vacancies than pure TiO2. The Ov sites can effectively reduce the adsorption and activation energy of COS and H2O. Benefiting from the ample Ov sites, the resulting CuTiO2-δ-F achieved nearly 100 % COS conversion at 70 °C and 93.5 % H2S yield at 130 °C, which is better than that of pure TiO2. Furthermore, in situ FT-IR measurements and density functional theory (DFT) calculations were performed to reveal the reaction pathway in COS hydrolysis.

A microwave plasma etching strategy for preparing oxygen-vacancy-rich NiCoO2 Nanoarrays for high-rate performance supercapacitor

Supercapacitors are vital for industries like automotive and energy storage. Transition metal oxides are promising electrode materials due to their diversity and high capacity. This study uses microwave plasma etching (MPE) to synthesize oxygen-vacancy-rich NiCoO2 nanoarrays (E-NCO) for supercapacitors. The etched NiCoO2 nanoarrays exhibit remarkable performance (1360.7 F g−1 at 1 A g−1) and excellent rate performance (996.7 F g−1 at 50 A g−1) in a three-electrode system. After assembling E-NCO-15 into a hybrid supercapacitor, it demonstrated a high energy density of 48.4 Wh kg−1 at the power density of 387.4 W kg−1, and even at the ultra-high power density of 19377.1 W kg−1, the energy density remains 15.2 Wh kg−1. Through the characterization of the material and an exploration of the reaction kinetics mechanism, it was discovered that MPE as a low-cost and easily controllable material modification method can introduce oxygen vacancies into the material, thereby enhancing both the material’s electrical conductivity and charge storage capacity. In addition, nanoarrays morphology provides more active sites and faster ion transport. These results highlight E-NCO’s potential for high-performance supercapacitors.

Scalable and economical production of oxygen deficient vanadium oxide with tunable vacancies concentration for bendable zinc ion batteries

Although vanadium oxides have high theoretical capacity and low cost, their practical application in aqueous zinc ion batteries (AZIBs) is bottlenecked by sluggish diffusion kinetics and capacity decline. Herein, the oxygen-deficient V2O5-x·nH2O (defined as VOd) with tunable oxygen vacancy concentration has been obtained via an economic and scalable method. The introduction of oxygen vacancies not only provides extra sites for Zn2+ storage, but also reduces the electrostatic barrier for Zn2+ intercalation, resulting in enhanced capacity and cycling stability. As a result, VOd cathode with proper amount of oxygen defect exhibits a high capacity of 415 mAh g−1 and energy density of 294 Wh kg−1 at 0.2 A g−1, estimating a roughly chemical costs of $64/kWH for VOd cathode. Besides, the VOd exhibits excellent stability at 20 A g−1 with average capacity decay of 0.004 % per cycle for 5000 cycles. Moreover, the bendable quasi-solid VOd//Zn battery maintains stable capacity of 200 mAh g−1 at 2 A g−1 even when repeatedly bending to straight angles. Therefore, the economical production of VOd cathode and construction of bendable quasi-solid battery provides a feasible way to boost the construction of efficient flexible energy storage devices and broadened application of AZIBs.

Facile synthesis of Ce(III)-rich cerium oxyhydroxide and its unselective adsorption of Sb(III) and Sb(V) via oxygen vacancies

The introduction of oxygen vacancies (OVs) into metal oxide materials is an effective method for modifying the surface properties of environmentally functional materials. However, limited attention has been paid to their roles as pollutant adsorbent. In this study, Ce(III)-enriched cerium oxyhydroxide particles (CeO(OH)2-OVs@CS) were prepared using a drop-in phase separation method and then used as adsorbents to address the challenges of conventional metal oxides that display notably lower adsorption efficiencies for Sb(V) than Sb(III). Within 60 min, more than 96 % of both Sb(III) and Sb(V) with an initial concentration of 50 mg/L were removed, with only a 2 % difference between them. XRD, XPS, EPR, and FT-IR results demonstrated that chitosan served as a carrier for Ce nanoparticles and, due to its reductive characteristics, enhanced the air stability of Ce(III), thereby creating more OVs. Meanwhile, chitosan's abundant functional groups such as OH, NH2, and CO in its structure can also facilitate the binding of Sb species onto CeO(OH)2. Density functional theory (DFT) calculations also indicated that antimonate ions were more prone to binding with OVs compared with defect-free crystal surfaces. Additionally, CeO(OH)2-OVs@CS showed great removal performance for organic ligands in antimony(III) potassium tartrate solution, and about 97 % of tartaric acid was removed simultaneously.

Triggering cationic/anionic hybrid redox stabilizes high-temperature Li-rich cathodes materials via three-in-one strategy

Efficiently advancing lithium-ion batteries toward high energy density entails overcoming challenges in Li-rich layered oxides, including severe voltage and capacity fading, irreversible oxygen escape and compromised thermal robustness due to the uncontrollable oxygen anionic redox (OAR). Herein, a three-in-one modification strategy, aim at strengthening the reversibility of OAR and structural integrity of MnO6 octahedron, is rationally introduced on Li1.2Mn0.53Ni0.20Co0.07O2 cathode through a universal H3BO3-treatment. Through the introduction of oxygen vacancies and gradient B-doping, the energy level of unhybridized O 2p states is decreased to narrow the band energy gap with transition metal (TM) band, which triggers cationic/anionic hybrid redox at high voltage, thereby stabilizing the peroxo-like (O2)n- species and hindering irreversible oxygen escape, while the lithium borate nano-coating serves to mitigate side reactions, particularly during charging at elevated temperatures. As a result, the modulated cathode exhibits notable capacity retention of 96.3 % after 500 cycles at 1 C with limited voltage fading rate (1.73 mV per cycle) and even stable cyclic performance at high temperature (60 °C). This approach provides an effective and straightforward method to tackle the voltage decay and capacity fading of high-energy Li-rich layered cathode materials.

Incorporation of Cu5FeS4 QDs with Abundant Oxygen Vacancy TiO2 QDs/TiO2 OVs: Double S-Scheme Photocatalysts for Effectual N2 Conversion to NH3 under Simulated Solar Light.

Photocatalytic N2 conversion to NH3 is a green, sustainable pathway with renewable energy sources and carbon neutrality. In this research, ternary TiO2 QDs/TiO2 OVs/Cu5FeS4 nanocomposites were prepared by an easy and affordable procedure and utilized to produce clean ammonia energy without a sacrificial agent. The amount of produced green ammonia by the optimum nanocomposite achieved was 17,274 μmol L-1 g-1, which was approximately 20.9, 6.48, 4.45, 2.26, and 1.45 times higher than those of commercial TiO2, TiO2 QDs, TiO2 OVs, Cu5FeS4, and TiO2 QDs/TiO2 OVs photocatalysts, respectively. Lattice compatibility through the developed homojunction within TiO2 QDs/TiO2 OVs and the integration of Cu5FeS4 nanoparticles led to the establishment of a double S-scheme homo/heterojunction system, which improved the photocatalytic activity by maintaining electrons and holes with high oxidation and reduction power and greatly reduced the recombination of charges, which led to the acceleration of charge transfer and migration. Besides, the promoted surface area compared to the pure components, introducing oxygen vacancies, and reducing the particle size boosted the photocatalytic N2 conversion to NH3. The results of this research are a basis for the rational design of homojunction/heterojunction visible-light-responsive systems for photocatalytic nitrogen fixation reactions.

Oxygen vacancy-rich high-pressure rocksalt phase of zinc oxide for enhanced photocatalytic hydrogen evolution

The generation of hydrogen as a clean energy carrier by photocatalysis, as a zero-emission technology, is of significant scientific and industrial interest. However, the main drawback of photocatalytic hydrogen generation from water splitting is its low efficiency compared to traditional chemical or electrochemical methods. Zinc oxide (ZnO) with the wurtzite phase is one of the most investigated photocatalysts for hydrogen production, but its activity still needs to be improved. In this study, an oxygen-deficient high-pressure ZnO rocksalt phase is stabilized using a high-pressure torsion (HPT) method, and the product is used for photocatalysis under ambient pressure. The simultaneous introduction of oxygen vacancies and the rocksalt phase effectively improved photocatalytic hydrogen production to levels comparable to benchmark P25 TiO2, due to improving light absorbance and providing active sites for photocatalysis without any negative effect on electron-hole recombination. These results confirm the high potential of high-pressure phases for photocatalytic hydrogen generation.

Oxygen-rich vacancies in micro-caged NiMn2O4 derived from metal-organic frameworks enabling high-performance lithium-ion batteries

Transition metal oxides (TMOs) are increasingly attracting the interest of researchers with advantages of high theoretical capacity, abundant reserves, and ease of preparation. However, low coulombic efficiency, severe volume expansion, and poor electronic conductivity severely limit their application. The introduction of oxygen vacancies as well as morphology modulation is currently an effective solution to the above problems. Herein, we have synthesized a series of different MOF-derived NiMn2O4 (NMO) anodes for lithium-ion battery via the proposed hydrothermal synthesis method. Through the rational introduction of oxygen vacancies, all the synthesized 1,4-dicarboxybenzene-NiMn2O4 (BDC-NMO), 1,3,5-Benzenetricarboxylic acid-NiMn2O4 (BTC-NMO) and 1,2,4,5-Benzenetetracarboxylic acid-NiMn2O4 (PMA-NMO) electrodes achieved excellent cycle stability performance and rate performance. Meanwhile, BTC-NMO achieves superior cycling performance of 940 mAh g−1 after 250 cycles at 0.1 A g−1 compared to BDC-NMO and PMA-NMO electrodes, which was attributed to its hollow micro-cage structure, which could effectively shorten the Li+ diffusion path, alleviate volume expansion during the cycling and provide more Li+ reaction active sites. Theoretical calculations and experimental studies indicated that oxygen vacancies could enhance electronic conductivity, improve Li+ diffusion kinetics and promote the contribution of pseudo-capacitance. This strategy of regulating the electronic structure and reaction kinetics through oxygen vacancies and the hollow micro-cage structure design provides ideas for the commercialization path of TMOs as anodes for Li-ion battery.

Enhanced Photocatalytic Degradation of Rhodamine B Dye by Iron-Doped Europium Oxide Nanoparticles.

As a wide-bandgap rare-earth oxide, Eu2O3 was often utilized as an auxiliary material of other photocatalysts because its photocatalytic performance was limited by the luminescence characteristics of Eu3+ and low light utilization. In this study, we improved the photocatalytic degradation performance of the Eu2O3 nanoparticles by doping with Fe cations. The Eu2O3 nanoparticles with different Fe-doping concentrations (1, 3, and 5%, noted as EF1.0, EF3.0, and EF5.0, respectively) were synthesized via chemical precipitation and calcination methods. It was found that doping could reduce Eu2O3's bandgap, which probably originated from the introduction of oxygen vacancies with lower energy levels than the conduction band of Eu2O3. Compared with the undoped Eu2O3 nanoparticles with a removal efficiency of 22% for degrading rhodamine B dye within 60 min, the photocatalytic degradation efficiencies of EF1.0, EF3.0, and EF5.0 were demonstrated to be improved to 42, 48, and 33%, respectively, and EF3.0's performance was the best. The enhanced photocatalytic performance of the doped samples was related to the oxygen vacancies acting as capture centers for electrons, such that the photogenerated electron-hole pairs were efficiently separated and the redox reactions on the surface of the nanoparticles were enhanced accordingly. Additionally, the enhanced light absorption and broadened spectral band further improved EF3.0's degradation efficiency.

Tuning charge transfer and ion diffusion in 3D nanotubular arrays by engineering vacancy and implanting sodiophilic seeds for dendrite-free sodium metal anodes

Sodium metal anode (SMA) stands out as a compelling choice for future high-energy Na batteries due to its high theoretical capacity and low redox potential. However, its widespread application is severely impeded by dendrite-related hazards. Designing a host for “hostless” SMA has emerged as a promising strategy to address its harmful dendrite growth. Recent studies highlight the effectiveness of low-tortuosity arrays in SMA for guiding rapid ion transport and achieving uniform Na deposition. Herein, a pioneering 3D host, Ag@H-TNTA, characterized by low-tortuosity hydrogenated TiO2-x nanotubular arrays decorated with silver nanocrystals, are unveiled for constructing fast, stable, and dendrite-free SMA. The strategic introduction of oxygen vacancies and the implantation of sodiophilic seeds enable the achievement of rapid and coordinated electronic/ion transport as well as uniform electric-field/ion flux distribution in the Ag@H-TNTA, ultimately facilitating uniform Na deposition. Consequently, Ag@H-TNTA electrode exhibits a dendrite-free plating morphology and maintains an impressive Coulombic efficiency of ≈ 98% over 600 cycles at 1 mA cm−2 with a capacity of 1 mAh cm−2. Outstanding cycling performances and high rate capabilities of Ag@H-TNTA-Na anode are also demonstrated in both symmetric and full cells, underscoring the potential of Ag@H-TNTA as a robust host for stable and dendrite-free SMA.

Adjusting photocatalytic hydrogen production of TiO2 hollow nanospheres through nitrogen-induced shallow trapping levels

N-doped titanium dioxide (TiO[Formula: see text] hollow nanospheres with abundant oxygen vacancies were successfully synthesized by coupling urea treatment and annealing in an N2 atmosphere. The pristine TiO2 hollow nanospheres exhibit a shallow donor level for electron trapping, while the urea treatment generates a N 2p acceptor level for hole trapping. After annealing in N2, the sufficient N atoms generate abundant oxygen vacancies for trapping electrons, resulting in further improved charge separation efficiency. The N-doped TiO2 exhibits the highest H2 evolution rate, reaching 2867[Formula: see text][Formula: see text]mol[Formula: see text]g[Formula: see text][Formula: see text]h[Formula: see text], which is six times higher than that of pristine TiO2 hollow nanospheres. The introduction of oxygen vacancies by interstitial N provides a promising way to improve the photocatalysis activity of photocatalysts.

Oxygen vacancy based WO3/SnO2-x promote electrochemical H2O2 accumulation by two-electron water oxidation reaction and toxic uniform dimethylhydrazine degradation

The key to constructing an anodic electro-Fenton system hinges on two pivotal criteria: enhancing the catalyst activity and selectivity in water oxidation reaction (WOR), while simultaneously inhibiting the decomposition of hydrogen peroxide (H2O2) which is on-site electrosynthesized at the anode. To address the issues, we synthesized novel WO3/SnO2-x electrocatalysts, enriched with oxygen vacancies, capitalize on the combined activity and selectivity advantages of both WO3 and SnO2-x for the two-electron pathway electrocatalytic production of H2O2. Moreover, the introduction of oxygen vacancies plays a critical role in impeding the decomposition of H2O2. This innovative design ensures that the Faraday efficiency and yield of H2O2 are maintained at over 80 %, with a noteworthy production rate of 0.2 mmol h−1 cm−2. We constructed a novel electro-Fenton system that operates using only H2O as its feedstock and applied it to treat highly toxic uniform dimethylhydrazine (UDMH) from rocket launch effluent. Our experiments revealed a substantial total organic carbon (TOC) removal, achieving approximately 90 % after 120 mins of treatment. Additionally, the toxicity of N-nitrosodimethylamine (NDMA), a byproduct of great concern, was shown to be effectively mitigated, as evidenced by acute toxicity evaluations using zebrafish embryos. The degradation mechanism of UDMH is predominantly characterized by the advanced oxidative action of H2O2 and hydroxyl radicals, as well as by complex electron transfer processes that warrant further investigation.

One-step in-situ construction engineering of ZnO-Zn2SnO4 heterojunction for deeply photocatalytic oxidation of nitric oxide

The generation of hazardous intermediates during the process of photocatalytic nitric oxide (NO) oxidation presents a tough issue. Herein, a one-step microwave strategy was employed to introduce oxygen vacancies (OVs) into zinc oxide-zinc stannate (ZnO-Zn2SnO4) heterojunction, resulting in an improvement in the photocatalytic efficiency for NO removal. The construction ZnO-Zn2SnO4 heterojunction with the OVs (ZSO-3) owns a significant contribution towards highly efficient electron transfer efficiency (99.7%), which renders ZSO-3 to exert a deep oxidation of NO-to-nitrate (NO3−) rather than NO-to-nitrite (NO2−) or NO-to-nitrogen dioxide (NO2). Based on the solid supports of experimental and simulated calculations, it can be found that OVs play an irreplaceable role in activating small molecules such as NO and O2. Moreover, the enhanced adsorption capacity of small molecules, which guarantees the high yield of active radical due to the formation of S-scheme heterojunction. This work illuminates a novel viewpoint on one-step in-situ route to prepare Zn2SnO4-based heterojunction photocatalyst with deep oxidation ability of NO-to-NO3−.

Spatial interfacial heterojunctions of TiO2 for photocatalytic degradation of toluene: Effects of interface amorphous region and oxygen vacancy

The catalytic activity of TiO2 is contingent upon its crystal structure and the optoelectronic properties associated with defects. In this study, a one-step method was used to synthesize TiO2 with a spatial interface of rutile/anatase phases, and a simple thermal annealing process was applied to optimize the amorphous regions and oxygen vacancies at the interface between the rutile and anatase phases of TiO2. High-resolution transmission electron microscopy (HRTEM) elucidates the evolution process of the amorphous domain at the interface, skillfully introducing oxygen vacancies at the heterojunction interface by modulating the amorphous domain. The obtained photocatalyst (TiO2–350 °C) after annealing exhibits an optimal interface structure, with its photocatalytic activity and stability in degrading toluene far superior to P25. Photocurrent and photoluminescence (PL) measurements affirm that the existence of interfacial oxygen vacancies heightens the efficiency of electron transfer at the interface, while surface oxygen vacancies significantly enhance the stability and mineralization rate of toluene degradation. The improved photocatalytic properties were attributed to the combined effects of surface/interface oxygen vacancies and spatial interface heterojunctions. The one-step synthesis method developed in this work provides a novel perspective on combining spatially interfaced anatase/rutile phases with surface/interfacial oxygen vacancies.

Graphene controlled solid-state growth of oxygen vacancies riched V2O5 catalyst to highly activate Fenton-like reaction

Fenton-like process based on metal oxide presents one of the most hoping strategies to generate reactive oxygen species to treat refractory pollutants. The introduction of oxygen vacancies (OVs) can enhance the catalytic performance of metal oxides in Fenton-like reaction. In this paper, a one-step all solid-state synthesis strategy is proposed to induce oxygen defects in V2O5, which uses graphene to engineer the crystallization process of V-based crystals. Such approach employs graphene as a solid-catalyst to promote growth of V-based crystals owing to the ions-π interactions between graphene and VCl3. The electron-donor OVs in V2O5@graphene can not only active H2O2 for the •OH generation, but also accelerate the reduction of V5+ and V4+, thereby ensuring defective V2O5@graphene/H2O2 system is 14.3, 28.2, and 17.3 times higher than that of graphene/H2O2, pure V2O5/H2O2 and graphene+V2O5/H2O2 (mechanical mixed system), respectively. Our study provides a novel synthetic strategy to design and prepare OVs-riched transition metal catalysts for developing advanced oxidation technologies toward higher sustainability and practicality.

Novel H4Nb6O17/BiOCl heterojunction with oxygen defects for boosting photodegradation activity under simulated solar light

The development of green, thorough and high-efficiency photocatalysts for tetracycline hydrochloride (TCH) degradation is a hot spot in environmental and energy fields. In this work, the H+-restacked H4Nb6O17 nanotubes (RHNT) were incorporated with BiOCl plates to successfully construct RHNT/BiOCl (RTB) composites with the 1D/2D heterostructure, which was beneficial to the charge carrier separation. The introduction of oxygen vacancies in RTB composites could promote the effective separation of charge carriers and the generation of reactive active species. The performance of the as-synthesized samples was evaluated by TCH photodegradation under simulated solar light. Compared to RHNT and BiOCl, the RTB composites, with an optimal sample of RTB-7, showed the enhanced photocatalytic activity for TCH degradation. The characterization results revealed that the enhanced TCH photodegradation activity for RTB composites was due to the synergistic effect of heterojunction formation and oxygen vacancies. During TCH photodegradation for RTB-7, the active radical species were determined by the radical trapping experiments and EPR spectra. The possible TCH photodegradation pathways and mechanism over RTB-7 were explored based on the characterization results. This work offers an effective approach for the rational design and construction of 1D/2D heterostructured photocatalysts with a high efficiency.