Operating Pressure Research Articles

Optimizing Harvesting Efficiency: Development and Assessment of a Pneumatic Air Jet Excitation Nozzle for Delicate Biostructures in Food Processing.

This study presents a new pneumatic air jet excitation nozzle, specifically designed for food processing applications. The device, which uses compressed air equipment and a precision solenoid valve, controls air discharge through a parametric air jet nozzle. Tests showed that the device could achieve shooting frequencies in the 40-45 Hz range, with operational pressures between 5 and 7 bar. A sensor system was used to measure the force generated by the device at different frequencies and pressures. Using the Design of Experiments (DOE) methodology, we identified optimal cavity designs for 5 and 6 bar pressures. These designs outperformed others in generating uniform force and maintaining consistent vibration voltage behavior. This highlights the efficacy of our approach in enhancing device performance under different conditions. The device's practical application in food processing was demonstrated, particularly in delicate tasks such as the selective harvesting of sensitive crops like coffee fruits. The precise vibrations generated by the device could potentially enhance harvesting efficiency while significantly reducing mechanical damage to plants. The results position the device as a compelling proof of concept, offering an alternative method for exciting biostructures in food processing. This device opens up new possibilities in agricultural and biological fields, providing a non-intrusive and practical approach to manipulating and interacting with delicate, contactless structures, with a specific focus on improving food processing efficiency and quality.

Influence of operating pressure on the durability of a satellite hydraulic motor supplied by rapeseed oil

This article describes the results of a durability test of a hydraulic satellite motor supplied by rapeseed oil. The tests were carried out on a test stand in a power recuperation system. The tests of the motor were carried out at a constant shaft speed for three fixed pressure drops in the motor. This made it possible to demonstrate the influence of the motor operating pressure on the durability of the satellite mechanism. The influence of the pressure drop in the motor and the influence of the operating time on the motor absorbency, on the torque on the motor shaft and the influence on the volumetric and hydraulic-mechanical efficiency are also shown. The basic relationship between the efficiency of the motor and the temperature rise in the motor is also described. The results of the calculations of the temperature rise in the motor are compared with the experimental results. The article also shows which components of the motor’s working mechanism wear out the fastest. The cause of the wear and failure is also explained.

Experimental and numerical investigation on latent heat/cold stores for advanced pumped-thermal energy storage

Pumped-thermal energy storage plays a pivotal role in large-scale harvesting and utilization for renewable resource endowments with intrinsic properties such as intermittency and instability. Here, we conducted detailed experimental and numerical studies on latent heat/cold stores of Brayton-like pumped-thermal energy storage. A demonstration thermal energy storage system with rated power of 20 kW including phase change materials (PCMs) preparation and structural design of energy storage units is synergistically designed and built. In this paper, the operating mechanism behind the theoretical experiment and control groups that raises the intake temperature through an air heater is uncovered and compared. Moreover, an auxiliary numerical model for further energy and exergy analyses is established to perfect the system-wide assessment. In terms of the first law of thermodynamics, the speed of energy storage and efficiency increase with higher operational pressures. For instance, system properties like roundtrip efficiency can reach up to 0.37 at an operating pressure of 0.7 MPa. As for systematic exergy despite the total destruction of thermal energy storage units amounts to 12.25 kWh the maximum exergy efficiency could reach 0.61 simultaneously.

New insights into antifouling property and interfacial mechanism in photo-Fenton membrane distillation

Membrane distillation (MD), boasting high interception efficiency and low operational pressures, emerges as an innovative membrane technology. However, the occurrence of membrane fouling due to interaction between natural organic matter (NOM) and inorganic ions during the MD process curtails water purification efficiency, thereby constraining its potential applications. To address this quandary, this study integrates sulfate radical-based advanced oxidation processes (SR-AOPs) into MD technology to bolster membrane fouling control. A straightforward hydrothermal method coupled with vacuum filtration was employed to synthesize a Co3O4/Nitrogen-modified carbon quantum dots (NCDs)/PVDF (CN-PVDF) membrane for the first time, which was utilized in the MD treatment of simulated humic acid (HA) wastewater. Under visible light irradiation (1.9 kW/m2), CN-PVDF membrane activation of peroxymonosulfate (PMS) effectively altered the chemical attributes of the MD feed solution and reduced organic matter concentration. Moreover, it dismantled the carboxyl sites on HA that interact with Ca2+, consequently attenuating the formation of organic–inorganic complex pollutants. The XDLVO analysis showcased that photo-Fenton oxidation led to a diminishment in pollutant hydrophobicity, correlating with a 17.59 kT reduction in pollutant-membrane adsorption and a 7.47 kT amplification in adhesion barriers. This strategy transformed the initial two-stage fouling mode into a singular one, which significantly decreased the flux decline and the fouling layer thickness. Furthermore, the CN-PVDF membrane demonstrated self-cleaning capabilities via photo-Fenton. This study advances an innovative approach to bolster the fouling resistance of MD membranes and provides substantial theoretical support for the integration of SR-AOPs and MD technologies.

Performance of different nebulizers in clinical use for Pressurized Intraperitoneal Aerosol Chemotherapy (PIPAC).

Technical ex-vivo comparison of commercial nebulizer nozzles used for Pressurized Intraperitoneal Aerosol Chemotherapy (PIPAC). The performance of four different commercial nebulizer nozzles (Nebulizer; HurriChemTM; MCR-4 TOPOL®; QuattroJet) was analysed concerning: i) technical design and principle of operation, ii) operational pressure as function of the liquid flow rate, iii) droplet size distribution via laser diffraction spectrometry, iv) spray cone angle, spray cone form as well as horizontal drug deposition by image-metric analyses and v) chemical resistance via exposing to a cytostatic solution and chemical composition by means of spark optical emission spectral analysis. The Nebulizer shows quasi an identical technical design and thus also a similar performance (e.g., mass median droplet size of 29 μm) as the original PIPAC nozzles (MIP/ CapnoPen). All other nozzles show more or less a performance deviation to the original PIPAC nozzles. The HurriChemTM has a similar design and principle of operation as the Nebulizer, but provides a finer aerosol (22 μm). The principle of operation of MCR-4 TOPOL® and QuattroJet differ significantly from that of the original PIPAC nozzle technology. The MCR-4 TOPOL® offers a hollow spray cone with significantly larger droplets (50 μm) than the original PIPAC nozzles. The QuattroJet generates an aerosol (22 μm) similar to that of the HurriChemTM but with improved spatial drug distribution. The availability of new PIPAC nozzles is encouraging but can also have a negative impact if their performance and efficacy is unknown. It is recommended that PIPAC nozzles that deviate from the current standard should be subject to bioequivalence testing and implementation in accordance with the IDEAL-D framework prior to routine clinical use.

Shipment lead time hedging and coordination in prefabricated construction supply chain

This paper aims to coordinate a shipment lead time hedging (SLTH) problem between a building contractor and a logistics provider in the prefabricated construction supply chain (PCSC). In the PCSC, untimely (early or late) delivery of prefabs can lead to project time and cost overruns. To mitigate this challenge, the building contractor requires the logistics provider to reduce the shipping time variability, which is termed the SLTH strategy. While this benefits the building contractor, it also puts more investment and operational pressures on the logistics provider. To solve this conflict, we introduce a coordination mechanism which involves two terms: an SLTH level related cost term is charged by the logistics provider to the building contractor, and a constant transfer term is adopted to fairly allocate the system surplus. Three decentralized models are investigated: i.e., two Stackelberg game models with alternative decision-making sequences and an equal power model. Further comparative analysis and numerical studies reveal that our proposed coordination mechanism increases the SLTH level and ensures a win–win situation. Moreover, some interesting managerial implications are derived.

Performance evaluation of modified pintle-type fuel injector for LRE (liquid rocket engine)

This research focuses on the fluid dynamics analysis and empirical validation of a modified pintle-type fuel injector through computational modeling. The primary aim is to assess the injector's performance metrics, including spray dispersion and orientation, flow velocity, turbulence levels, and vortex formation, by adjusting the pintle's positioning, which inherently modulates the flow rate. The observed effects draw parallels with the interactions seen in conical spray and hollow cone swirl atomizers. A pintle-type fuel injector model was developed using geometric design software, and computational fluid dynamics simulations were conducted to ensure effective fuel and oxidizer blending. This study evaluates key performance indicators, such as thrust output and combustion efficiency, under specific operational pressures and velocities at the injector's orifice.

Uplifting the study of the inline inspection technique on the buckling pipelines in pipeline integrity management strategy

This work reports the development of inline inspection (ILI) methodology to enhance the pigging activity for the dented pipeline, facilitate the pigging process to prevent Pipeline Inspection Gauge (PIG) from getting stuck and improve the safety passage for buckled pipelines. The recent report unveils the condition of the UNPIGGABLE pipelines, which reduce the inner diameter of pipelines to 257.51 mm, equivalent to 27.58 % of the initial diameter and restricts the pigging activity. In this report, the pull-through test coupled with the collapsibility test was conducted. The success of the test above allows the ILI equipment based on the magnetic flux leakage (MFL) technique to record the internal and external wall loss inwardly and geometric defect on diameter of the pipelines. The prepared artificial dented pipeline was made before it underwent several tests. Based on the pull-through test, the maximum force of 27000 N is more significant than the pipeline operating pressure to enable the MFL tool to pass through the pipelines despite exhibiting the geometry anomaly. Compressing the opposite magnetic yoke of the collapsibility test is critical, showing that the ILI MFL tool reaches its maximum compression of 242 mm. The value is lower than the minimum internal diameter of 257 mm. The ILI results show that the highest metal loss was achieved at 73 % at 15504 m at the bottom of the inspected pipelines. At the same time, the dented area reduces to more than 6 % of the pipelines’ nominal outer diameter and imposes the pipe’s integrity status to red. The distinctive result of the research can be used to model the future unprecedented pigging process when buckles appear in pipelines

Failure behavior of pressure compensating emitter under different operation pressures in drip irrigation systems

Pressure compensating emitters (PCE) can maintain a consistent irrigation flow rate under varying pressures through its internal compensation diaphragm and effectively improve the irrigation uniformity of drip irrigation systems. However, the PCE function is prone to failure, particularly when using marginal water, which can cause various technical and economic problems. To date, little is known about the failure behavior of PCE. This study investigated the effects of three pressures (0.1Mpa, 0.2Mpa, and 0.3Mpa) on the failure behavior of PCE. Then the dynamic changes in clogging substances and diaphragm performances in PCE channel were monitored. The results showed that as the system operation increased, the performance of PCE gradually decreased. The CU>80% running time was 172.8–634.9 h, and the flow index >0.2 running time was 120.1–768.1 h. The failure of PCE is primarily caused by two factors: clogging of the PCE flow channel and deterioration of the diaphragm mechanical performances. The flow rate of PCE increased by 22.6% on average at 0.3Mpa compared to 0.1Mpa, and clogging substances in the PCE flow channel decreased by 19.8%. Meanwhile, increasing the operating pressure improved the mechanical performance of the diaphragm. Under the operating pressure of 0.3Mpa, the diaphragm’s elasticity and hardness increased by 14.6% and 12.8%, respectively. Therefore, this study is of significance in popularizing PCE drip irrigation technology and marginal water utilization.

Research on the helium seepage mechanism in the strata surrounding bedded salt cavern helium storage and its tightness evaluation

To improve the safety and scale of helium storage, large-scale or strategic helium storage in underground salt caverns can be implemented. Salt caverns leached from bedded salt formations have been considered as potential underground storage sites for helium in China. However, the salt formations are typical lacustrine sedimentary rocks with an interbedded structure, thus the sealing feasibility of such salt caverns must be evaluated before they can be used. To this end, the helium seepage equation in deep strata and permeability evolution function are derived with the help of experimental results and theoretical analysis. Based on these, a helium seepage model considering slippage effect and threshold pressure gradient is proposed to evaluate the sealing properties of salt caverns for helium storage. The analysis results indicate that it is feasible to use bedded salt mine formations for helium storage when the formations permeability parameters and reservoir design parameters meet the long-term tightness evaluation criteria, including permeability, porosity, salt pillar width, salt roof thickness and operating pressure and duration. More importantly, specific recommendations are provided for the operation parameters, design parameters and formation permeability thresholds of salt caverns for ensuring helium storage safety while maintaining stable cavern operations. The threshold permeability of the target salt formations should be approximately 1 × 10−18 m2 to ensure tightness. The minimum and maximum operating pressure are recommended to be 10 MPa and 18 MPa respectively for 50 years of this helium storage. The salt pillar width should be 300 m, and the salt roof thickness should be 40 m.

Mo-based MXenes as highly selective two-electron oxygen reduction catalysts for H2O2 production

Hydrogen peroxide production through the electrochemical two-electron oxygen reduction presents a compelling alternative to the anthraquinone process due to the cheap starting materials and low operating temperature and pressure. Transition metal species featuring with multi-active sites, offer high electrochemical activity and selectivity. MXenes, distinguished by excellent electrical conductivity and the two-dimensional structure facilitating smooth ion transportation, further enhance the prospects of this production approach. In this study, three Mo-based MXenes were synthesized: Mo2TiC2Fx, Mo2Ti2C3Fx and Mo2CFx. Among these, Mo2TiC2Fx emerged as the most promising catalyst for 2e−ORR, achieving a remarkable H2O2 yield of up to 0.54 mol·gcat−1·h−1. Moreover, it also exhibits a high H2O2 selectivity ranging from 81.3 % at 0.2 V to 94.1 % at 0.6 V vs. RHE, coupled with an impressive faradaic efficiency of 76.4 % at 0.4 V using H-cell. Further analysis indicates that the superior 2e−ORR performance can be attributed to the presence of metallic Mo on the surface of Mo2TiC2Fx.

Project Risk Analysis and Early Warning of Culture and Tourism Group Financial Leasing Company

Under the background of strict regulation, due to the cyclical adjustment of the financial leasing industry, some top companies have maintained a growth trend in asset size and net profit. Internal differentiation has emerged in the financial leasing industry, increasing operational pressure, and a slowing trend in asset size growth. Although the overall pressure on credit quality has eased, downward pressure on asset quality is widespread, and the recovery period for narrowing profit space is still long. With the continuous upgrading and iteration of digitization, intelligence, and specialization, Culture and Tourism Group Financial Leasing Company should strengthen its professional ethics, improve its risk analysis and prediction capabilities, design integrated business guidelines for due diligence information collection and risk analysis, rely on big data to build a leasing asset identification, evaluation, monitoring, and early warning system, and establish a comprehensive, multi angle, and lean risk analysis and early warning mechanism. Through case analysis, problems are identified in a timely manner, and continuous reflection and improvement are made. Business process diagrams are drawn according to different scenarios, crisis warning indicators are set up, and a lean risk management team is formed. Crisis warning signals are continuously tracked and released, and processes and asset quality management are continuously improved. A lean risk control system is established to reduce risk losses and create benefits for the enterprise.

Experimental demonstration of a sorption-enhanced methanation (SEM) cyclic process on a lab-scale TRL-3 fixed bed reactor

In this work, the scaling-up of the sorption-enhanced methanation (SEM) process to a TRL-3 fixed bed reactor has been demonstrated. The SEM process for synthetic natural gas (SNG) production consists mainly of two stages: in the first stage, the zeolite facilitates the removal of a product from the methanation reaction, thereby enhancing CO/CO2 conversion; in the second stage, zeolite regeneration takes place. The functional materials chosen were a zeolite 4A and a Nickel-based catalyst, selected for their high H2O adsorption capacity and high catalytic activity, respectively. Various operational variables, including temperature and pressure, were optimized during both SEM and regeneration stages to enhance the performance of the process. Optimum regeneration conditions consisted of pressure swing operation—from 10 bar during the SEM reaction to atmospheric pressure—while maintaining a constant temperature at 230°C. These operating conditions were tested for more than 20 SEM/regeneration cycles using a feed gas containing H2/CO/CO2. Stable performance throughout the cycles was fulfilled, reaching a CH4 purity of 100 % during 25 min during SEM for the operating conditions chosen. Finally, the number of reactors needed to obtain a continuous stream of CH4 was calculated resulting in a process productivity of 8.00×10-4 molCH4/kgcat·s.

Particle swarm optimization of electric power generation via green hydrogen considering the performance of the electrolyzer cell

The replacement of energy generation models, from fossil fuels to carbon neutral ones, requires a significant transformation in the generation and consumption of electricity. This work highlights Green Hydrogen as an essential potential to intensify the energy generation process based on renewable sources. The article presents two studies on energy generation models, via Green Hydrogen: Case (i), study of the behavior of the Electric Activation Voltage with ohmic loss influenced by the control variables Electric Current and Operating Temperature. Case (ii), study of the behavior of the Electric Activation Voltage with ohmic loss influenced by the control variables Electric Current and Operating Pressure. For both cases, a computational model stands out, the Proton Exchange Membrane electrolyzer cells, indicated for the generation of renewable energy, from Green Hydrogen. For both cases, a Bioinspired Computing methodology was applied in order to optimize the process. The Optimization technique means, among the various definitions, determining the best set of results, considering the restrictions of the studied phenomenon. Studies indicate that this strategy is increasingly intrinsic to our reality. This paper advocates Particle Swarm Optimization as a mechanism capable of finding the best set of solutions for mathematical models related to Energy Systems. The Swarm Algorithm can be represented as a set of particles that navigate through a space of solutions, where the main element of this method is the exchange of information between the particles of the population, which allows collective mobilization towards the optimal solution. In this case specifically, the values of Electrical Voltage, Electrical Current, Operating Temperature and Pressure form the Particle Examination. The results were exceptional for the Green Hydrogen energy generation system studied. The Particle Swarm Optimization Algorithm was applied to the objective function of multiple variables and satisfactorily incorporated the restrictions and conditions of the electrolysis system. The measurements obtained highlight that the Optimal Values are lower than the Average Values, for each variable analyzed in energy generation, in an electrolyzer. The solution achieved will be of great applicability in the study of energy efficiency in structures linked to this relevant category of renewable energy generation.

Development of a diafiltration-nanofiltration-reverse osmosis (DiaNF-RO) process for ion fractionation towards resource recovery in seawater desalination

A diafiltration-nanofiltration-reverse osmosis (DiaNF-RO) process is introduced to achieve solutes fractionation of divalent/monovalent ions, i.e., Mg/Na, to enable resource recovery in seawater desalination and brine management. The diafiltration process is applied at the NF stage (i.e., DiaNF) to enhance the Mg/Na fractionation performance of NF (i.e., SF1Mg-Na), while the RO is incorporated to produce desalinated water as well as diluent required by the DiaNF. By initiating the ion fractionation at the pre-treatment rather than post-treatment (i.e., RO-NF), the DiaNF-RO mitigates challenges of high concentration in RO brine management, which includes limitation of maximum allowable operating pressure and high energy requirement. The semi-empirical model, with at least 77.4 % accuracy, is first applied to simulate the performance of DiaNF-RO at different operating conditions and configurations (i.e., multi-stage and recycling). The sensitivity analysis then suggests that dilution should only occur in the last NF stage and without any retentate recycling, while NF pressure and element number should be optimized. Using NF membrane with SFMg-Na of 1.28 at 10 bar and feed seawater of 35 g/L TDS, the optimal 4-stage DiaNF-RO design achieves maximum SF1Mg-Na of 12.19 at 5.72 kWh/m3, or a minimum energy consumption of 5.41 kWh/m3 at SF1Mg-Na of 7.04.

Numerical study on effect of operating pressures on CRKEC-based two-stage ejector

The two-stage ejector mixing-diffuser section in this study was computed using the Redlich-Kwong equation of state. The ejector was designed based on the constant rate of kinetic energy change (CRKEC) approach. The water vapor mixing diffuser profile and flow properties were calculated using a one-dimensional gas dynamic model. For the numerical investigation, the estimated geometrical profile based on the input design and operating conditions was utilized. ANSYS-Fluent 14.0 was em-ployed for the numerical study. The analysis was conducted under both on-design and off-design scenarios using the standard k-ε turbulence model. The impact of operating factors on flow behavior and entrainment ratios was investigated at off-design conditions. The findings demonstrated that the operational total pressures of the primary, secondary, and exit flows are a function of the two-stage ejector (TSE) entrainment ratio. With a higher exit pressure and more secondary/entrained flows, the entrain-ment ratio increases. However, altering the primary flow pressure in ways other than for the design conditions reduces the entrainment ratio.

Projected effective energy stored of Zhangshu salt cavern per day in CAES in 2060

As a large-scale energy storage technology, compressed air energy storage (CAES) has the advantages of high efficiency and high reliability. This paper analyzed the feasibility of CAES cavern constructed in salt mine with multi-interlayer in Zhangshu, Jiangxi Province. Salt mine in Zhangshu is a typical bedded rock salt, and a method for calculating the cavern volume in Zhangshu was proposed. Using the proposed volume calculation method, it is expected that the volume of Zhangshu salt caverns can reach 27,840,000 m3 by 2060. By modelling the geomechanics used to calculate its stability. Based on the results of the simulation, the recommended operating pressure is 8.5–11.5 MPa. Finally, If this volume is used for CAES, the cycle pressure is assumed to be 8.5–11.5 MPa, energy storage efficiency of 50 %, the daily effective energy storage is 8.062 × 1014 J. This study will guide the development of the Zhangshu Salt Mine, provide lessons for similar areas and have a positive impact on the energy transition in Jiangxi.

Comprehensive examination of topologically optimized thermo-fluid heat sinks

This study investigates the thermal performance of topologically optimized heat sinks. The primary aims are to conduct a comprehensive parametric study, compare thermal outputs with the benchmark model, and validate numerical simulations through experimental testing. Multi-objective topology optimization is formulated based on thermal compliance and power dissipation. Selected optimized models were built and tested. The parametric study revealed promising design variables, leading to numerical convergence with interconnected flow paths. The promising variables were found under weighted thermal compliances (wh) between 0.3 and 0.9 and targeted liquid fractions (θFV) between 0.5 and 0.8. Additionally, at low operating pressures, for example, at 0.01 kPa, the temperature difference between optimized and benchmark models could be as much as 30 °C. Nonetheless, the temperature difference between both models became smaller at higher operating pressures. Furthermore, the comparison of temperature measurements, pressure drops, and thermal imaging showed reasonable agreement between experimental and numerical results. Additionally, the effect of design variables on thermal performance was confirmed through experiments. The heat sink with higher wh exhibited a lower temperature than that of the model with lower wh. In summary, this research highlights the crucial role of design variables in achieving a balance between temperature and pressure drop.

Application of SSA-KNN Algorithm in Fault Analysis of Power Metering Automation System

In view of the great pressure of operation and maintenance of power energy data collection terminal after putting into operation, an intelligent fault diagnosis system for power equipment terminal based on computer was developed. This paper proposes an Agent based on autonomy, promotility, cooperation and interactivity. It also provides a flexible interactive communication interface and load balancing optimization method. It can meet a variety of data transmission specifications and a large number of data service transmission requirements. The SA-KNN algorithm is used to analyze the power quality. Methods The operation data of maintenance electricity were collected. Learning and cluster analysis are carried out by using relevant data, and the calculation model of automatic check device failure is established. At the same time, the outlier points in the collected data are used to accurately locate the fault points of the power grid. This method can realize the comprehensive fault diagnosis of the power grid by using the interaction between the power grid and each component.

Facet and dual vacancy engineering-boosting BiOBr for enhanced CO2 and epoxide cycloaddition reaction under mild and cocatalyst-free conditions: Double substrate active sites and activated surface bromine ions synergy

Among the many strategies for CO2 resource utilization, the synthetic technology of cyclic carbonates with 100 % atom economy through CO2and epoxide is one of the most industrially viable routes, but its efficiency has been severely hampered by the lack of highly active catalytic sites. Moreover, due to the intrinsic thermodynamic stability and kinetic inertia of CO2 and the higher energy barrier of the ring-opening reaction of epoxides, the heterogeneous catalytic conversion of CO2 highly depends on harsh operating conditions, high temperatures and pressures, and the incorporation of cocatalysts. The development of efficient heterogeneous catalysts for CO2 conversion under cocatalyst-free and mild conditions has always been a challenge. Herein, we have proposed a synergetic strategy of facet and vacancy engineering for the construction of highly efficient heterogeneous catalyst BiO1-xBr1-y-(010) for CO2 cycloaddition, where introducing the OVs-BrVs pairs into typical (010) facets BiOBr with simultaneous surface Lewis acid sites Bi3+ and nucleophilic sites Br−. By combining theoretical calculations and a series of systematic experiments, such as CO2 temperature-programmed desorption, electron paramagnetic resonance and fluorescence probe analysis experiments, the introduced OVs-BrVs pair can not only form Bi3+-Bi(3-x)+ dual active sites on the surface, which activate PO and CO2 respectively to reduce the energy barrier of CO2 insertion, but also activate Br− near BrVs to enhance their nucleophilic attacking ability and reduce the energy barrier of epoxides ring-opening. As a result, the BiO1-xBr1-y-(010) with abundant surface OVs-BrVs pairs showed a high cyclic carbonates conversion of 99 % with 100 % selectivity under cocatalyst-free and mild conditions, far surpassing most heterogeneous catalytic systems. This work provides a completely new strategy to construct high-performance heterogeneous CO2 cycloaddition catalysts through a simple facet and vacancy engineering strategy to overcome the harsh operating conditions limitation and the use of cocatalysts.