Greenhouse Effect Research Articles

Deep ocean warming-induced El Niño changes

The deep ocean, a vast thermal reservoir, absorbs excess heat under greenhouse warming, which ultimately regulates the Earth’s surface climate. Even if CO2 emissions are successfully reduced, the stored heat will gradually be released, resulting in a particular pattern of ocean warming. Here, we show that deep ocean warming will lead to El Niño-like ocean warming and resultant increased precipitation in the tropical eastern Pacific with southward shift of the intertropical convergence zone. Consequently, the El Niño-Southern Oscillation shifts eastward, intensifying Eastern Pacific El Niño events. In particular, the deep ocean warming could increase convective extreme El Niño events by 40 to 80% relative to the current climate. Our findings suggest that anthropogenic greenhouse warming will have a prolonged impact on El Niño variability through delayed deep ocean warming, even if CO2 stabilization is achieved.

Evaluation of ethanol-gasoline blends in SI engines using experimental and ANN techniques

Fuel combustion has become a major global concern, with much research focusing on the various emissions resulting from different types of fuels. Due to the harmful pollutant emissions from fossil fuels, the world has turned to renewable and alternative fuels to limit toxic emissions and greenhouse effects. Ethanol is a biofuel that, when used in spark ignition engines with gasoline can improve the octane number, combustion efficiency, and produce less emissions. The current research studies the effect of different ethanol blends E0, E5, E10, and E15 with gasoline 92 on engine performance parameters and emissions of a GX35 four-stroke engine at different engine speeds. The results along the speed range reveal that increasing ethanol amount leads to an average increase of 2.7%, 1%, and 1.1% in brake power (BP), brake thermal efficiency (BTE), and CO2 emissions, respectively. Meanwhile, it causes an average decrease of 28 °C, 3%, 15 ppm, and 0.18% in exhaust gas temperature (EGT), brake-specific fuel consumption (BSFC), HC, and CO emissions respectively. Moreover, the current study develops an Artificial Neural Networks (ANN) model for predicting the performance and emissions of spark ignition (SI) engines. Python programming language is used for ANN coding to train and validate the ANN model with E15. Regression plots were generated to visualize the correlation between the target and predicted data, indicating outstanding performance. The results confirmed the model’s reliability for BP, EGT, CO, CO2, and HC parameters with R2 values more than 0.99 and with acceptable performance for BSFC and BTE with R2 of 0.9339, and 0.9708, respectively. To ensure that the is no overfitting during the ANN study, we used different statistical methods, such as validation set, cross-validation, and learning curves.

Improving the roughness of copper working electrode through electroless deposition for carbon dioxide reduction reaction

Electrocatalytic CO2 conversion into usable fuels (CO, CH4, C2H4, and HCOOH) is a promising approach to mitigate the greenhouse effect and the energy deficit. Herein, we employ the wet etching process to significantly enhance the surface roughness of the copper foil, followed by deposition of Cu particles on the surface-etched copper foil (Cu NPs/Cu foil) for electrochemical CO2 reduction. FESEM and AFM results confirms the morphology and roughness changes. Introducing glycine to the electrolyte increase the Faraday efficiency (FE) of the resulting products. Upon adding 5 × 10−5 mM glycine significantly improves the FEs 10.1 % CO, 8.7 % CH4, 11.7 % C2H4, and 44.5 % HCOOH, with 75.0 % as C1 and C2 compounds. Concurrently, hydrogen production decreases to 20.2 % at a potential of –1.4 V utilizing roughened Cu NPs/Cu foil as a catalyst. These results shed light on the factors contributing to increased hydrocarbons and formic acid production with enhanced surface roughness of Cu foil.

Research on Residential Interior Design and Energy Saving Optimization with Sustainable Low-carbon Development

The escalating crisis of global warming, driven by the emission of greenhouse gases, poses a formidable challenge for humanity as a whole. Notably, the construction industry contributes significantly to the global greenhouse gas inventory. Consequently, prioritizing low-carbon construction assumes paramount importance in mitigating the pervasive impact of the greenhouse effect on a global scale. Such an endeavor stands as a crucial safeguard for ensuring the sustainable development of human civilization. Therefore, from the perspective of low- carbon building design optimization research is an important part of low-carbon building. From the perspective of architectural design, this paper summarizes that low-carbon building design should pay attention to following aspects: reasonable use of natural lighting and natural ventilation, reduce the carbon emission value of building use stage; Taking the transformation project of the former engineering Institute of Southeast University as an example, this paper probes into the effect of design optimization on reducing carbon emissions, and quantitatively studies the relationship between the design optimization of lighting, ventilation and envelope structure materials and the reduction of building carbon emissions. The Angle selection of roof skylight is studied from the Angle of day- lighting optimization, the size and position of facade opening and the strategy of natural ventilation path are studied from the Angle of ventilation optimization. The indoor ventilation further reduces the refrigeration energy consumption, which is 22.1% less than before the renovation, and the roof reduces the heat gain by 22%-32%.e.

Magnetocaloric Refrigeration in the Context of Sustainability: A Review of Thermodynamic Bases, the State of the Art, and Future Prospects

At present, one of the main challenges that industry faces is its impact on global warming, linked to the greenhouse effect and ozone hole problems. These two environmental issues have not yet been solved completely and, concerning the industrial cold sector, countries are making various decisions on refrigerants. Magnetic refrigeration potentially represents a less impactful refrigeration technology. In this review, the physical basis of magnetic refrigeration is analysed, in order to propose this technology for industrial use.

Human-induced warming accelerates local evapotranspiration and precipitation recycling over the Tibetan Plateau

The Tibetan Plateau faces changing precipitation and environmental conditions affecting alpine ecosystems and downstream freshwater sustainability. While aerosol influence has been highlighted, how human-induced greenhouse warming impacts the plateau’s moisture recycling remains unclear. Here we show that the Tibetan Plateau’s recent precipitation changes result from enhanced precipitation recycling and moisture convergence that offset the decline in monsoon- and westerly-associated moisture transport based on 40-year Lagrangian simulations and water budget analyses. Local evapotranspiration is observed to increase faster in percentage than precipitation, a trend expected to continue in future warming scenarios according to climate projections. Greenhouse gas emission causes widespread wetting while weakening the southerly monsoons across the Himalayas, heightening the sensitivity of precipitation to evapotranspiration and thereby local land surface changes. This trend exacerbates vulnerability in the water cycle of high mountain Asia, calling for proactive management to address potential risks and ensure future water and food security in Asia.

Impact of an unprecedented marine heatwave on extremely hot summer over Northern Japan in 2023

Possible local influence of an extreme marine heatwave is investigated on unprecedentedly hot summer around northern Japan in 2023. Sea-surface temperatures (SSTs) and subsurface ocean temperatures around northern Japan were also unprecedentedly high in the summer. This was especially the case off the east coast of Japan, where cool Oyashio water was replaced with much warmer water due to a striking poleward meander of the Kuroshio Extension persistent from the spring. Particularly amplified near-surface air temperature anomalies and even stronger warm anomalies in the subsurface ocean suggest that the marine heatwave acted to sustain the atmospheric heatwave. Anomalous upward of latent and sensible heat fluxes from the warmed sea surface are indicative of local oceanic impact. The warm SST anomalies reduced the lower-tropospheric stratification to maintain unfavourable condition for low-level cloud formation, which in turn led to increased surface insolation for further SST warming as positive feedback. The increased moisture in the warmed lower troposphere contributed to the enhanced surface downward longwave radiation. This enhanced greenhouse effect acted not only as positive feedback on the warm SST anomalies that increased evaporation but also as a contributor for the extreme warmth over northern Japan landmass.

Utilization of coconut shell activated carbon to generate electrical energy using sodium chloride electrolyte

Fossil fuels that are used to generate electrical energy are running low. Besides that, energy generated from fossil fuels causes global warming and climate change due to gas emissions such as carbon dioxide, leading to a greenhouse effect. In addition, the development of small electronic devices has created power demands, from initially in milli watt (mW), to microwatt (μW) level for wireless sensor networks, which generally use batteries as a power supply. Therefore, environmentally friendly and renewable materials like coconut shells are needed to generate electrical energy. This research aims to generate electrical energy from a model using coconut shell activated carbon with sodium chloride (NaCl) electrolyte. The electrical energy generation model is composed of counter electrode–electrode–counter electrode. The electrode used was coconut shell–activated carbon. Three counter electrodes were used: aluminum, zinc and copper plates. The electrolyte used was sodium chloride (NaCl) solution. The electrolyte was injected between the electrode and the counter electrode, and heat was applied. When the electrolyte was injected into the electrical energy generation model, interaction occurred between the ions from the electrolyte and the functional groups, the pores of the activated carbon, and the counter electrode, and then electrons were released. The research results show that the voltage produced due to an increase in temperature up to ΔT=54 °C, is 0.875 volts for aluminum, 0.767 volts for zinc and 0.091 volts for copper. The average thermal voltage sensitivity (dV/dT) for aluminum is 68.99297 mV/°C, while that for zinc is 61.34319 mV/°C, and copper is 7.02533 mV/°C. The currents produced by aluminum, zinc and copper are 5.9 μA, 3.8 μA and 0.157 μA, respectively

The performance of CO2 reduction by dielectric barrier discharge plasma coupled Cu-Ni binary silicon-based composites

As a major greenhouse gas, the rational conversion and utilization of CO2 can help reduce carbon emissions and mitigate the greenhouse effect. In this study, mesoporous SiO2 as a carrier, with CuO and NiO employed to construct a binary metal composite silica-based catalyst, coupled with dielectric barrier discharge (DBD) plasma, for the conversion of CO2. Physicochemical analysis confirmed the successful introduction of CuO into the mesoporous SiO2. NiO and CuO bimetals were dispersed on SiO2 surfaces with large specific surface areas, ensuring an optimal distribution of metal oxide. Gas chromatography was utilized to investigate the performance of DBD-coupled x%CuO-3 %NiO/Si for CO2 conversion. The results indicated that the CuO-NiO binary composite silica catalysts significantly improved CO2 conversion, CO yield, and energy efficiency compared to the monometallic 3 %NiO/Si materials. Further microstructural analysis of the 9 %CuO-3 %NiO/Si catalyst revealed near-elliptic particles with dimensions of 200 by 500 nm and a large number of irregular fine particles attached to the surface. When the CuO loading reached an optimal level and the input power was set at 30 W, the energy efficiency of the 9 %CuO-3 %NiO/Si catalyst increased by 119.6 %. The CuO-NiO binary composite Si-based catalyst developed in this study boasts simple operation and environmental friendliness, making it highly significant for CO2 treatment.

Carbon-based brilliance: a novel approach to renewable energy in radiotherapy centers.

The energy produced from other sources which does neither come from fossil fuels nor contribute in the production of any greenhouse effects that causes climate changes is called as 'Alternative Energy'. Since our world's primary energy sources such as coal, oil and natural gases are exploited to a greater extent, we are in an urge to switch to an alternative energy. Scattered radiation, a common byproduct in radiation therapy and diagnostic radiology, presents a unique opportunity in the realm of alternative energy. As a potential source of interference, scattered radiation can be repurposed to contribute to sustainable energy solutions. Addressing the issue of scattered radiation wastage and utilizing it for alternative energy, an activated carbon-based solar cell emerges as a solution. This solar cell, a conventional one in which cadmium Telluride is replaced by coconut shell based carbon material, has the potential in producing a significant amount of electrical energy by utilizing scattered radiation from radiotherapy and radiology machines. Furthermore, this activated carbon based-material undergoes thorough characterization into various teletherapy and radiology machines, and it can be seamlessly integrated into clinical practices.

A Review of the Utilization of CO2 as a Cushion Gas in Underground Natural Gas Storage

A cushion gas is an indispensable and the most expensive part of underground natural gas storage. Using CO2 injection to provide a cushion gas, not only can the investment in natural gas storage construction be reduced but the greenhouse effect can also be reduced. Currently, the related research about the mechanism and laws of CO2 as a cushion gas in gas storage is not sufficient. Consequently, the difference in the physical properties of CO2 and CH4, and the mixing factors between CO2 and natural gas, including the geological conditions and injection–production parameters, are comprehensively discussed. Additionally, the impact of CO2 as a cushion gas on the reservoir stability and gas storage capacity is also analyzed by comparing the current research findings. The difference in the viscosity, density, and compressibility factor between CO2 and CH4 ensures a low degree of mixing between CO2 and natural gas underground, thereby improving the recovery of CH4 in the operation process of gas storage. In the pressure range of 5 MPa–13 MPa and temperature range of 303.15 K–323.15 K, the density of CO2 increases five to eight times, while the density of natural gas only increases two to three times, and the viscosity of CO2 is more than 10 times that of CH4. The operation temperature and pressure in gas storage should be higher than the temperature and pressure in the supercritical conditions of CO2 because the diffusion ability between the gas molecules is increased in these conditions. However, the temperature and pressure have little effect on the mixing degree of CO2 and CH4 when the pressure is over the limited pressure of supercritical CO2. The CO2, with higher compressibility, can quickly replenish the energy of the gas storage facility and provide sufficient elastic energy during the natural gas production process. In addition, the physical properties of the reservoir also have a significant impact on the mixing and production of gases in gas storage facilities. The higher porosity reduces the migration speed of CO2 and CH4. However, the higher permeability promotes diffusion between gases, resulting in a higher degree of gas mixing. For a large inclination angle or thick reservoir structure, the mixed zone width of CO2 and CH4 is small under the action of gravity. An increase in the injection–production rate intensifies the mixing of CO2 and CH4. The injection of CO2 into reservoirs also induces the CO2–water–rock reactions, which improves the porosity and is beneficial in increasing the storage capacity of natural gas.

Global Trends in the Research and Development of Petrochemical Waste Gas from 1981 to 2022

As a highly energy-intensive and carbon-emitting industry with significant emissions of volatile organic compounds (VOCs), the petroleum and chemical industry is a major contributor to the global greenhouse effect and ozone layer destruction. Improper treatment of petrochemical waste gas (PWG) seriously harms human health and the natural environment. This study uses CiteSpace and VOSviewer to conduct a scientometric analysis of 1384 scholarly works on PWG and carbon sequestration published between 1981 and 2022, revealing the basic characteristics, knowledge base, research topic evolution, and research hotspots of the field. The results show the following: (1) In the early stages of the petrochemical industry, it was processed tail gas, plant leakage waste gas, and combustion flue gas that were investigated in PWG research. (2) Later, green environmental protection technology was widely studied in the field of PWG treatment, such as biotechnology, catalytic oxidation technology, membrane separation technology, etc., in order to achieve efficient, low energy consumption and low emissions of waste gas treatment, and the number of publications related to this topic has increased rapidly. In addition, researchers studied the internet of things and technology integration, such as the introduction of artificial intelligence, big data analysis, and other technologies, to improve the accuracy and efficiency of exhaust gas monitoring, control, and management. (3) The department has focused on how to reduce emissions by optimizing petrochemical process lines or improving energy efficiency. Emission reduction and low-carbon transition in the petrochemical industry will become the main trend in the future. Switching from renewable carbon to feedstock carbon derived from captured carbon dioxide, biomass, or recycled chemicals has become an attractive strategy to help curb emissions from the chemical industry. The results of our analysis can provide funding agencies and research groups with information to better understand the global trends and directions that have emerged in this field from 1981 to 2022 and serve as a reference for future research.

Decreased ENSO post-2100 in response to formation of a permanent El Niño-like state under greenhouse warming

Under transient greenhouse warming, El Niño-Southern Oscillation (ENSO) is projected to increase pre-2100, accompanied by an easier establishment of atmospheric convection in the equatorial eastern Pacific, where sea surface temperature (SST) warms faster than surrounding regions. After 2100, how ENSO variability may change remains unknown. Here we find that under a high emission scenario, ENSO variability post-2100 reverses from the initial increase to an amplitude far smaller than that of the 20th century. The fast eastern warming persists and shrinks the equatorial Pacific non-convective area, such that establishing convection in the non-convective area, as during an El Niño, requires smaller convective anomaly, inducing weaker wind anomalies leading to reduced ENSO SST variability. The nonlinear ENSO response is thus a symptom of the persistent El Niño-like warming pattern. Therefore, the oscillatory ENSO impact could be replaced by that from the permanent El Niño-like mean condition with cumulative influences on affected regions.

Modulated turbulent convection: a benchmark model for large scale natural flows driven by diurnal heating

Our life is strongly affected by turbulent convective flows, driven by time-dependent thermal forcing, especially diurnal heating of the Earth’s surface by the Sun. In a laboratory experiment, we investigate their analogues: We study complex and extraordinary properties of turbulent buoyancy driven flows generated due to periodic modulation of the temperature of the plates of a Rayleigh–Bénard cell, with amplitudes both smaller and larger than either the positive or negative mean temperature difference between the top and bottom. We probe the turbulent flow of our working fluid – cryogenic helium gas – using temperature sensors placed in the cell interior and embedded in its plates. We discuss spatial and temporal structure of the heat flow, generalize validity of Nusselt versus Rayleigh number scaling Nu ∝\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\propto$$\\end{document} Raγ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^\\gamma$$\\end{document} with γ≈1/3\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\gamma \\approx {1/3}$$\\end{document} at very high Ra for modulated convection and argue that this system represents a benchmark model which helps us understand the energy budget of ocean currents or weather formation on Earth subject to diurnal Sun heating as well as similar natural flows on Earth-like planets.

Socio-environmental Analysis and Financial Profitability of the Efficiency of Agricultural Machinery on Rice and Maize Fields in Benin

Agriculture requires sustainable mechanization in Benin to increase production. This study analyzes the socio-environmental impact and financial efficiency of mechanized agricultural equipment. We adopted a methodology that integrated bibliographic research, observations, in-depth analyses and surveys in Lalo. Data analysis indicates that agricultural mechanization improves soil permeability and reduces the greenhouse effect. Socially, it contributes to the reducing of poverty, working time and labour costs. However, constraints such as the unavailability of tools, breakdowns, and negative impacts such as soil depletion and air pollution are noted. It causes unemployment and requires significant investments. The majority (88.89%) of the machines were mainly rented, costing 70,000 FCFA for small equipment and 50,000 FCFA for heavy equipment per hectare. For rice production, the income of a producer using motorized tillers far exceeds (109,400 F) that of using traditional tools (43,632 F). An increase of 60.12% (65,768 F). The income of a producer using tractors for corn production is higher (80,700 F) than that using traditional tools (48,599 F). We observe an increase of 39.78 per cent (32,101 F). Repairs are complex. Recommendations, such as access to agricultural credit, improved access to equipment, and the training of producers, aim to promote sustainable mechanization.

Перспективы использования баз спутниковых данных эмиссии парниковых газов при мониторинге объектов добывающей промышленности

Emissions of the greenhouse gases, particularly methane and carbon dioxide, by the mining, processing, and energy industries can significantly affect pollution in the bottom layer of the atmosphere, aerosols, and the atmospheric greenhouse effect. Continuous monitoring of emissions is the basis for developing effective strategies to reduce greenhouse gas emissions. Satellite missions are actively used for this purpose. The article provides an overview and description of the existing databases of greenhouse gas emissions obtained based on satellite measurements. The monitoring methodology involves satellite spectroscopy aimed at analyzing the spectral characteristics of light absorbed by the atmosphere. The results of measurements by satellite spectrometers show the total molar mass of substances throughout the atmospheric column. Global satellite monitoring allows identifying zones of anomalous concentration and identifying new sources of greenhouse gases, comparing them with the ground-based measurements of pollutants.

Modified TiO2/In2O3 heterojunction with efficient charge separation for visible-light-driven photocatalytic CO2 reduction to C2 product

Utilizing sunlight to convert CO2 into chemical fuels could address the greenhouse effect and fossil fuel crisis. Heterojunction structure catalysts with oxygen vacancy are attractive in the field of photocatalytic CO2 conversion. Herein, a modified TiO2/In2O3 (R-P25/In2O3−x) type II heterojunction composite with oxygen vacancies is designed for photocatalytic CO2 reduction, which exhibits excellent CO2 reduction activity, with a C2 selectivity of 56.66% (in terms of Relectron). In situ Fourier-transform infrared spectroscopy (DRIFTS) and time-resolved photoluminescence (TR-PL) spectroscopy are used to reveal the intermediate formation of the photocatalytic mechanism and photogenerated electron lifetime, respectively. The experimental characterizations reveal that the R-P25/In2O3−x composite shows a remarkable behavior for coupling C–C bonds. Besides, efficient charge separation contributes to the improved CO2 conversion performance of photocatalysts. This work introduces a type II heterojunction composite photocatalyst, which promotes understanding the CO2 reduction mechanisms on heterojunction composites and is valuable for the development of photocatalysts.

Carbon Emission Accounting and Reduction for Buildings Based on a Life Cycle Assessment: A Case Study in China’s Hot-Summer and Warm-Winter Region

At the 75th United Nations General Assembly, China committed to peaking carbon dioxide emissions by 2030 and achieving carbon neutrality by 2060. In response, the national standard “General Specification for Building Energy Conservation and Utilization of Renewable Energy” has been adopted across 20 provinces and cities in seven major regions, including North China, Northeast China, and South China. These regions have implemented stringent energy-saving and emission reduction reviews and quota requirements. Despite this, there is limited research on comprehensive life cycle carbon emission calculations and carbon reduction designs. This study addresses this gap by focusing on economically developed regions with high population density and substantial energy-saving potential, specifically targeting the warm winter and hot summer regions of China. Using a commercial building in Shenzhen as a case study, we established a carbon emission accounting model based on the life cycle assessment (LCA) method. We calculated carbon emissions during the material phase using the project’s bill of quantities and relevant carbon emission factors. Additionally, we used the CEEB 2023 software to design energy-saving and emission reduction solutions for the building. Our comparative analysis reveals that the new design reduces the carbon emissions of the case study building by 13.5%. This reduction not only mitigates the environmental impact of construction but also contributes to the fight against the greenhouse effect, supporting the broader goal of sustainable development.

A dataset of hidden small non-coding RNA in the testis of heat-stressed models revealed by Pandora-seq

Infertility, a worldwide reproductive health concern, impacts approximately one in five couples. Male infertility, stemming from spermatogenic dysfunction and reduced sperm quality, stands as a primary factor contributing to infertility. Given the global decrease in male fertility linked to environmental factors like the greenhouse effect, it is crucial to develop a comprehensive understanding of how increased temperatures impact both the quantity and quality of sperm. In this study, we utilized Pandora-seq technology to detect the small non-coding RNAs (sncRNAs) expression profile in the testicular tissue of heat-stressed mice. The investigation explores the dynamic shifts in sncRNAs within the mouse testis under heat stress, including miRNAs, tsRNAs, piRNAs, rsRNAs and other sncRNAs. Furthermore, we successfully identified differentially expressed sncRNAs in testicular tissues before and after heat stress. Subsequently, we conducted functional enrichment analysis on the potential predicted target genes of differentially expressed miRNAs and tsRNAs. These datasets will constitute a valuable foundational resource for further investigations into the decline in male reproductive capacity triggered by heat stress.

Local microenvironment modulation of zirconium-porphyrinic frameworks for CO2 reduction

Solar-powered photocatalysis offers a sustainable strategy to convert carbon dioxide into valuable fuels, which mitigates the energy crisis and the greenhouse effect. Nevertheless, exploring efficient, selective, stable, and environmentally friendly photocatalysts for CO2 reduction continues to meet a significant challenge. Herein, two iron-porphyrinic zirconium-based metal–organic frameworks, Zr6O4(OH)4(FeTCBPP)3 (MOF-526-H) and Zr6O4(OH)4(FeTCBPP-NH2)3 (MOF-526-NH2) were achieved by the integration of the light-harvesting sites and catalytic centers into one phase (FeTCBPP = iron 5,10,15,20-tetra[4-(4′-carboxyphenyl)phenyl]-porphyrin, FeTCBPP-NH2 = iron 5,10,15,20-tetra[4-(4′-carboxyphenyl)-2-aminophenyl]-porphyrin), which were employed as a couple of models for CO2 photoreduction. MOF-526-NH2 exhibited excellent CO2 reduction with a CO yield of 21.2 mmol·g−1 in the absence of any photosensitizer under visible light, which was 4-fold higher than that of MOF-526-H. Additionally, MOF-526-NH2 showed no significant reduction in CO production during the four rounds, indicating that MOF-526-NH2 possessed good stability. The presence of amino groups in MOF-526-NH2 played an important role in adjusting the micro-environment and electronic structure, which was beneficial to CO2 enrichment and light absorption, and thus improved CO2 photoreduction performance. Based on the density functional theory calculations, a possible mechanism of photocatalytic CO2 reduction over porphyrinic MOFs was proposed.