Investigation on cost-effective composites for CO2 adsorption from post-gasification residue and metal organic framework.

Cost-effective CO2 adsorbents are gaining increasing attention as viable solutions for mitigating climate change. In this study, composites were synthesized by electrochemically combining the post-gasification residue of Macadamia nut shell with copper benzene-1,3,5-tricarboxylate (CuBTC). Among the different composites synthesized, the ratio of 1:1 between biochar and CuBTC (B 1:1) demonstrated the highest CO2 adsorption capacity. Under controlled laboratory conditions (0°C, 1 bar, without the influence of ambient moisture or CO2 diffusion limitations), B 1:1 achieved a CO2 adsorption capacity of 9.8 mmol/g, while under industrial-like conditions (25°C, 1 bar, taking into account the impact of ambient moisture and CO2 diffusion limitations within a bed of adsorbent), it reached 6.2 mmol/g. These values surpassed those reported for various advanced CO2 adsorbents investigated in previous studies. The superior performance of the B 1:1 composite can be attributed to the optimization of the number of active sites, porosity, and the preservation of the full physical and chemical surface properties of both parent materials. Furthermore, the composite exhibited a notable CO2/N2 selectivity and improved stability under moisture conditions. These favorable characteristics make B 1:1 a promising candidate for industrial applications.

Carbon emissions in China's steel industry from a life cycle perspective: Carbon footprint insights.

China is the most important steel producer in the world, and its steel industry is one of the most carbon-intensive industries in China. Consequently, research on carbon emissions from the steel industry is crucial for China to achieve carbon neutrality and meet its sustainable global development goals. We constructed a carbon dioxide (CO2) emission model for China's iron and steel industry from a life cycle perspective, conducted an empirical analysis based on data from 2019, and calculated the CO2 emissions of the industry throughout its life cycle. Key emission reduction factors were identified using sensitivity analysis. The results demonstrated that the CO2 emission intensity of the steel industry was 2.33 ton CO2/ton, and the production and manufacturing stages were the main sources of CO2 emissions, accounting for 89.84% of the total steel life-cycle emissions. Notably, fossil fuel combustion had the highest sensitivity to steel CO2 emissions, with a sensitivity coefficient of 0.68, reducing the amount of fossil fuel combustion by 20% and carbon emissions by 13.60%. The sensitivities of power structure optimization and scrap consumption were similar, while that of the transportation structure adjustment was the lowest, with a sensitivity coefficient of less than 0.1. Given the current strategic goals of peak carbon and carbon neutrality, it is in the best interest of the Chinese government to actively promote energy-saving and low-carbon technologies, increase the ratio of scrap steel to steelmaking, and build a new power system.

Anionic Metal-Organic Framework Derived Cu Catalyst for Selective CO2 Electroreduction to Hydrocarbons.

Metal-organic frameworks (MOFs)-related Cu materials are promising candidates for promoting electrochemical CO2 reduction to produce valuable chemical feedstocks. However, many MOF materials inevitable undergo reconstruction under reduction conditions; therefore, exploiting the restructuring of MOF materials is of importance for the rational design of high-performance catalyst targeting multi-carbon products (C2). Herein, a facile solvent process is choosed to fabricate HKUST-1 with an anionic framework (a-HKUST-1) and utilize it as a pre-catalyst for alkaline CO2RR. The a-HKUST-1 catalyst can be electrochemically reduced into Cu with significant structural reconstruction under operating reaction conditions. The anionic HKUST-1 derived Cu catalyst (aHD-Cu) delivers a FEC2H4 of 56% and FEC2 of ≈80% at -150 mA cm-2 in alkaline electrolyte. The resulting aHD-Cu catalyst has a high electrochemically active surface area and low coordinated sites. In situ Raman spectroscopy indicates that the aHD-Cu surface displays higher coverage of *CO intermediates, which favors the production of hydrocarbons.

Porous Bi Nanosheets Derived from ß-Bi2O3 for Efficient Electrocatalytic CO2 Reduction to Formate.

The electrochemical CO2 reduction reaction (ECO2RR) is a promising strategy for converting CO2 into high-value chemical products. However, the synthesis of effective and stable electrocatalysts capable of transforming CO2 into a specified product remains a huge challenge. Herein, we report a template-regulated strategy for the preparation of a Bi2O3-derived nanosheet catalyst with abundant porosity to achieve the expectantly efficient CO2-to-formate conversion. The resultant porous bismuth nanosheet (p-Bi) not only exhibited marked Faradaic efficiency of formate (FEformate), beyond 91% in a broad potential range from -0.75 to -1.1 V in the H-type cell, but also demonstrated an appreciable FEformate of 94% at a high current density of 262 mA cm-2 in the commercially important gas diffusion cell. State-of-the-art X-ray absorption near edge structure spectroscopy (XANES) and theoretical calculation unraveled the distinct formate production performance of the p-Bi catalyst, which was cocontributed by its smaller size, plentiful porous structure, and stronger Bi-O bond, thus accelerating the absorption of CO2 and promoting the subsequent formation of intermediates. This work provides an avenue to fabricate bismuth-based catalysts with high planar and porous morphologies for a broad portfolio of applications.

Study of different pre-treatments in the comparison of the efficacy of photodynamic therapy for moderate to severe acne vulgaris.

OBJECTIVE: To evaluate the efficacy of CO2 fractional laser and microneedling pretreatment combined with ALA-PDT for moderate-to-severe acne, aiming to optimize clinical treatment. METHODS: Patients were randomly divided into three groups: Group A (CO2 fractional laser + ALA-PDT), Group B (microneedling + ALA-PDT), and Group C (ALA-PDT). Each group underwent photodynamic therapy once a week for 3 weeks. Efficacy was assessed at the end of the 4th week, and recurrence was assessed at the end of the 12th week. RESULTS: A total of 150 patients with moderate to severe acne were included in this study, with 50 patients in each group. Four weeks after the end of treatment, the effective rates were 88% for Group A, 62% for Group B, and 36% for Group C. Statistically significant differences were found between the groups (P < 0.05), with Group A showing superior efficacy compared to Group B (P < 0.05). No serious systemic or local adverse reactions were observed in any group. No recurrence was seen in any group 12 weeks after the end of treatment, and some patients continued to show improvement in skin lesions over time. CONCLUSION: Both the CO2 fractional laser group and the microneedling group improved the efficacy of photodynamic therapy for moderate to severe acne compared to the control group, with the CO2 fractional laser group demonstrating better efficacy and fewer adverse effects.

Translational insights into the hormetic potential of carbon dioxide: from physiological mechanisms to innovative adjunct therapeutic potential for cancer.

Background: Carbon dioxide (CO2), traditionally viewed as a mere byproduct of cellular respiration, plays a multifaceted role in human physiology beyond simple elimination through respiration. CO2 may regulate the tumor microenvironment by significantly affecting the release of oxygen (O2) to tissues through the Bohr effect and by modulating blood pH and vasodilation. Previous studies suggest hypercapnia (elevated CO2 levels) might trigger optimized cellular mechanisms with potential therapeutic benefits. The role of CO2 in cellular stress conditions within tumor environments and its impact on O2 utilization offers a new investigative area in oncology. Objectives: This study aims to explore CO2's role in the tumor environment, particularly how its physiological properties and adaptive responses can influence therapeutic strategies. Methods: By applying a structured translational approach using the Work Breakdown Structure method, the study divided the analysis into six interconnected work packages to comprehensively analyze the interactions between carbon dioxide and the tumor microenvironment. Methods included systematic literature reviews, data analyses, data integration for identifying critical success factors and exploring extracellular environment modulation. The research used SMART criteria for assessing innovation and the applicability of results. Results: The research revealed that the human body's adaptability to hypercapnic conditions could potentially inform innovative strategies for manipulating the tumor microenvironment. This could enhance O2 utilization efficiency and manage adaptive responses to cellular stress. The study proposed that carbon dioxide's hormetic potential could induce beneficial responses in the tumor microenvironment, prompting clinical protocols for experimental validation. The research underscored the importance of pH regulation, emphasizing CO2 and carbonic acid's role in modulating metabolic and signaling pathways related to cancer. Conclusion: The study underscores CO2 as vital to our physiology and suggests potential therapeutic uses within the tumor microenvironment. pH modulation and cellular oxygenation optimization via CO2 manipulation could offer innovative strategies to enhance existing cancer therapies. These findings encourage further exploration of CO2's therapeutic potential. Future research should focus on experimental validation and exploration of clinical applications, emphasizing the need for interdisciplinary and collaborative approaches to tackle current challenges in cancer treatment.

Evidence on C-C Coupling to Acetate as Key Reaction Intermediate in Photocatalytic Reduction of CO2 over Pt/TiO2.

Photocatalytic conversion of CO2 with H2O is an attractive application that has the potential to mitigate environmental and energy challenges through the conversion of CO2 to hydrocarbon products such as methane. However, the underlying reaction mechanisms remain poorly understood, limiting real progress in this field. In this work, a mechanistic investigation of the CO2 photocatalytic reduction on Pt/TiO2 is carried out using an operando FTIR approach, combined with chemometric data processing and isotope exchange of (12CO2 + H2O) toward (13CO2 + H2O). Multivariate curve resolution analysis applied to operando spectra across numerous cycles of photoactivation and the CO2 reaction facilitates the identification of principal chemical species involved in the reaction pathways. Moreover, specific probe-molecule-assisted reactions, including CO and CH3COOH, elucidate the capacity of selected molecules to undergo methane production under irradiation conditions. Finally, isotopic exchange reveals conclusive evidence regarding the nature of the identified species during CO2 conversion and points to the significant role of acetates resulting from the C-C coupling reaction as key intermediates in methane production from the CO2 photocatalytic reduction reaction.

Highly Selective SO2 Capture by Triazine-Functionalized Triphenylamine-Based Nanoporous Organic Polymers.

The emissions of sulfur dioxide (SO2) from combustion exhaust gases pose significant risks to public health and the environment due to their harmful effects. Therefore, the development of highly efficient adsorbent polymers capable of capturing SO2 with high capacity and selectivity has emerged as a critical challenge in recent years. However, existing polymers often exhibit poor SO2/CO2 and SO2/N2 selectivity. Herein, we report two triazine-functionalized triphenylamine-based nanoporous organic polymers (ANOP-6 and ANOP-7) that demonstrate both good SO2 uptake and high SO2/CO2 and SO2/N2 selectivity. These polymers were synthesized through cost-effective Friedel-Crafts reactions using cyanuric chloride, 3,6-diphenylaminecarbazole, and 2,2',7,7'-tetrakis(diphenylamino)-9,9'-spirobifluorene. The resultant ANOPs are composed of triazine and triphenylamine units and feature an ultramicroporous structure. Remarkably, ANOPs exhibit impressive adsorption capacities for SO2, with uptakes of approximately 3.31-3.72 mmol·g-1 at 0.1 bar, increasing to 9.52-9.94 mmol·g-1 at 1 bar. The static adsorption isotherms effectively illustrate the ability of ANOPs to separate SO2 from SO2/CO2 and SO2/N2 mixtures. At 298 K and 1 bar, ANOP-6 shows outstanding selectivity toward SO2/CO2 (248) and SO2/N2 (13146), surpassing all previously reported triazine-based nanoporous organic polymers. Additionally, dynamic breakthrough tests demonstrate the superior separation properties of ANOPs for SO2 from an SO2/CO2/N2 mixture. ANOPs exhibit a breakthrough time of 73.1 min·g-1 and a saturated SO2 capacity of 0.53 mmol·g-1. These results highlight the exceptional adsorption properties of ANOPs for SO2, indicating their promising potential for the highly efficient capture of SO2 from flue gas.

Effects of atmospheric CO2 concentration on transpiration and leaf elongation responses to drought in Triticum aestivum, Lolium perenne and Festuca arundinacea.

BACKGROUND AND AIMS: Leaf elongation is vital for Poaceae species' productivity, influenced by atmospheric CO2 concentration ([CO2]) and climate-induced water availability changes. Although [CO2] mitigates the effects of drought on reducing transpiration per unit leaf area, it also increases total leaf area and water use. These complex interactions associated with leaf growth pose challenges in anticipating climate change effects. This study aims to assess [CO2] effects on leaf growth response to drought in perennial ryegrass (Lolium perenne), tall fescue (Festuca arundinacea) and wheat (Triticum aestivum). METHODS: Plants were cultivated in growth chambers with [CO2] at 200 or 800 ppm. At leaf six to seven unfolding, half of the plants were subjected to severe drought treatment. Leaf elongation rate (LER) was measured daily, whereas plant transpiration was continuously recorded gravimetrically. Additionally, water-soluble carbohydrate (WSC) content along with water and osmotic potentials in the leaf growing zone were measured at drought onset, mid-drought and leaf growth cessation. KEY RESULTS: Elevated [CO2] mitigated drought impacts on LER and delayed growth cessation across species. A positive correlation between LER and soil relative water content (SRWC) was observed. At the same SRWC, perennial grasses exhibited a higher LER with elevated [CO2], likely due to enhanced stomatal regulation. Despite stomatal closure and WSC accumulation, CO2 did not influence nighttime water potential or osmotic potential. The marked increase in leaf area across species resulted in similar (wheat and tall fescue) or higher (ryegrass) total water use by the experiment's end, under both watered and unwatered conditions. CONCLUSIONS: In conclusion, elevated [CO2] mitigates the adverse effects of drought on leaf elongation in three Poaceae species, due to its impact on plant transpiration. Overall, these findings provide valuable insights into CO2 and drought interactions that may help anticipate plant responses to climate change.

Photothermal Synergistic Effect Induces Bimetallic Cooperation to Modulate Product Selectivity of CO2 Reduction on Different CeO2 Crystal Facets.

Product selectivity of solar-driven CO2 reduction and H2O oxidation reactions has been successfully controlled by tuning the spatial distance between Pt/Au bimetallic active sites on different crystal facets of CeO2 catalysts. The replacement depth of Ce atoms by monatomic Pt determines the distance between bimetallic sites, while Au clusters are deposited on the surface. This space configuration creates a favourable microenvironment for the migration of active hydrogen species (*H). The *H is generated via the activation of H2O on monatomic Pt sites and migrate towards Au clusters with a strong capacity for CO2 adsorption. Under concentrated solar irradiation, selectivity of the (100) facet towards CO is 100%, and the selectivity of the (110) and (111) facets towards CH4 is 33.5% and 97.6%, respectively. Notably, the CH4 yield on the (111) facet is as high as 369.4 µmol/g/h, and the solar-to-chemical energy efficiency of 0.23% is 33.8 times higher than that under non-concentrated solar irradiation. The impacts of high-density flux photon and thermal effects on carriers and *H migration at the microscale are comprehensively discussed. This study provides a new avenue for tuning the spatial distance between active sites to achieve optimal product selectivity.

Fabrication of rGO-bridged TiO2/g-C3N4 Z-scheme Nanocomposites via Pulsed Laser Ablation for Efficient Photocatalytic CO2 Reduction.

Highly efficient photocatalysts can be fabricated using favorable charge transfer nanocomposite channel structures. This study adopted pulsed laser ablation in liquid (PLAL) to obtain rGO-bridged TiO2/g-C3N4 (rGO-TiO2/g-C3N4) photocatalytic Z-scheme without the need for noble metals. In addition to evaluating the resulting nanocomposite's (comprising rGO nanosheets, TiO2 nanotubes, and g-C3N4 nanosheets) CO2 reduction effectiveness, its chemical, morphological, structural, and optical characteristics were examined using various analytical techniques. The findings revealed a synergistic interaction between g-C3N4 and TiO2, suggesting the presence of unique interfacial bonding, as well as enhanced visible light absorption. Notably, the ternary rGO-TiO2/g-C3N4 Z-scheme exhibits an excellent photocatalytic performance by photocatalytically converting CO2 into CO and CH4, with 81% selectivity towards the CO and 1.91% apparent quantum efficiency at 420 nm. Thus, the findings can pave the way for various Z-scheme systems in wide photocatalytic applications.

Visible Light-sensitized CO2 Methanation along a Relaxed Heat Available Route.

In photocatalysis, the resulted heat by the relaxation of most of incident light no longer acts as the industrially favorite driving force back to the target photo-reaction due to more or less the negative relation between photocatalytic efficiency and temperature. Here, we reported a visible light-sensitized protocol that completely reversed the negatively temperature-dependent efficiency in photo-driven CO2 methanation with saturated water vapor. Uniform Pt/N-TiO2/PDI self-assembly material decisively injects the excited electron of PDI sensitizer into N-TiO2 forming Ti-H hydride which is crucially temperature-dependent nucleophilic species to dominate CO2 methanation, rather than conventionally separated and trapped electrons on the conductor band. Meanwhile, the ternary composite lifts itself temperature from room temperature to 305.2 °C within 400s only by the failure excitation upon simulated sunlight of 2.5 W/cm2, and smoothly achieves CO2 methanation with a record number of 4.98 mmol g-1 h-1 rate, compared to less than 0.02 mmol g-1 h-1 at classic Pt/N-TiO2/UV photocatalysis without PDI sensitization. This approach can reuse ~53.9% of the relaxed heat energy from the incident light thereby allow high-intensity incident light as strong as possible within a flowing photo-reactor, opening the most likely gateways to industrialization.

Electrolyte-Electrocatalyst Interfacial Effects of Polymeric Materials for Tandem CO2 Capture and Conversion Elucidated Using In Situ Electrochemical AFM.

Integrating CO2 capture and electrochemical conversion has been proposed as a strategy to reduce the net energy required for CO2 regeneration in traditional CO2 capture and conversion schemes and can be coupled with carbon-free renewable electricity. Polyethylenimine (PEI)-based materials have been previously studied as CO2 capture materials and can be integrated in these reactive capture processes. PEI-based electrolytes have been found to significantly increase the CO2 loading, and impact selectivity and rate of product formation when compared to the conventional aqueous electrolytes. However, the influence of these materials at the catalyst-electrode interface is currently not well understood. In this study, PEI-based electrolytes were prepared and their impact on the morphology of a silver electrode performing electrochemical CO2 reduction (CO2R) was studied using in situ electrochemical atomic force microscopy (EC-AFM). The presence of PEI on the electrode surface could be distinguished based on nanomechanical properties (DMT modulus), and changes were observed as negative polarization was applied, revealing a reorganization of the PEI chains due to electrostatic interactions. These changes were impacted by the electrolyte composition, including the addition of supporting electrolyte KHCO3 salt, as well as CO2 captured by the PEI-based electrolyte, which minimized the change in surface mechanical properties and degree of PEI alignment on the electrode surface. The changes in surface mechanical properties were also dependent on the PEI polymer length, with higher molecular weight PEI showing different reconfiguration than the shorter polymer brushes. The study highlights that the choice of polymer material, the electrolyte composition, and CO2 captured impact the near-electrode environment, which has implications for CO2R, and presents EC-AFM as a new tool that can be used to probe the dynamic behavior of these interfaces during electrocatalysis.

Electron-Efficient Co-electrosynthesis of Formates from CO2 and Methanol Feedstocks.

The electrochemical conversion of CO2 into valuable chemicals using renewable electricity shows significant promise for achieving carbon neutrality and providing alternative energy storage solutions. However, its practical application still faces significant challenges, including high energy consumption, poor selectivity, and limited stability. Here, we propose a hybrid acid/alkali electrolyzer that couples the acidic CO2 reduction reaction (CO2RR) at the cathode with alkaline methanol oxidation reaction (MOR) at the anode. This dual electro-synthesis cell is implemented by developing Bi nanosheets as cathode catalysts and oxide-decorated Cu2Se nanoflowers as anode catalysts, enabling high-efficiency electron utilization for formate production with over 180% coulombic efficiency and more than 90% selectivity for both CO2RR and MOR conversion. The hybrid acid/alkali CO2RR-MOR cell also demonstrates long-term stability exceeding 100 hours of continuous operation, delivers a formate partial current density of 130 mA cm-2 at a voltage of only 2.1 V, and significantly reduces electricity consumption compared to the traditional CO2 electrolysis system. This study illuminates an innovative electron-efficiency and energy-saving techniques for CO2 electrolysis, as well as the development of highly efficient electrocatalysts.

Exploiting CO2 laser to boost graphite inks electron transfer for fructose biosensing in biological fluids.

The possibility to print electronics by means of office tools has remarkedly increased the possibility to design affordable and robust point-of-care/need devices. However, conductive inks suffer from low electrochemical and rheological performances limiting their applicability in biosensors. Herein, a fast CO2 laser approach to activate printed carbon inks towards direct enzymatic bioelectrocatalysis (3rd generation) is proposed and exploited to build biosensors for D-fructose analysis in biological fluids. The CO2 laser treatment was compared with two lab-grade printed transducers fabricated with solvent (SB) and water (WB) based carbon inks. The use of the laser revealed significant morpho-chemical variations on the printed inks and was investigated towards enzymatic direct catalysis, using Fructose dehydrogenase (FDH) integrated into entirely lab-produced biosensors. The laser-driven activation of the inks unveils the inks' direct electron transfer (DET) ability between FDH and the electrode surface. Sub-micromolar limits of detection (SB-ink LOD = 0.47 µM; WB-ink LOD = 0.24 µM) and good linear ranges (SB-ink: 5-100 µM; WB-ink: 1-50 µM) were obtained, together with high selectivity due to use of the enzyme and the low applied overpotential (0.15 V vs. pseudo-Ag/AgCl). The laser-activated biosensors were successfully used for D-fructose determination in complex synthetic and real biological fluids (recoveries: 93-112%; RSD ≤8.0%, n = 3); in addition, the biosensor ability for continuous measurement (1.5h) was also demonstrated simulating physiological D-fructose fluctuations in cerebrospinal fluid.

Regulating Local Electron Density of Cyano Sites in Graphitic Nitride Carbon by Giant Internal Electric Field for Efficient CO2 Photoreduction to Hydrocarbons.

Selective photocatalytic CO2 reduction to high-value hydrocarbons using graphitic carbon nitride (g-C3N4) polymer holds great practical significance. Herein, the cyano-functionalized g-C3N4 (CN-g-C3N4) with a high local electron density site is successfully constructed for selective CO2 photoreduction to CH4 and C2H4. Wherein the potent electron-withdrawing cyano group induces a giant internal electric field in CN-g-C3N4, significantly boosting the directional migration of photogenerated electrons and concentrating them nearby. Thereby, a high local electron density site around its cyano group is created. Moreover, this structure can also effectively promote the adsorption and activation of CO2 while firmly anchoring *CO intermediates, facilitating their subsequent hydrogenation and coupling reactions. Consequently, using H2O as a reducing agent, CN-g-C3N4 achieves efficient and selective photocatalytic CO2 reduction to CH4 and C2H4 activity, with maximum rates of 6.64 and 1.35 µmol g-1 h-1, respectively, 69.3 and 53.8 times higher than bulk g-C3N4 and g-C3N4 nanosheets. In short, this work illustrates the importance of constructing a reduction site with high local electron density for efficient and selective CO2 photoreduction to hydrocarbons.

Estimating global 0.1° scale gridded anthropogenic CO2 emissions using TROPOMI NO2 and a data-driven method.

Satellite remote sensing is a promising approach for monitoring global CO2 emissions. However, existing satellite-based CO2 observations are too coarse to meet the requirements of fine-scale global mapping. We propose a novel data-driven method to estimate global anthropogenic CO2 emissions at a 0.1° scale, which integrates emissions inventories and satellite data while bypassing the inadequate accuracy of CO2 observations. Due to the co-emitted anthropogenic emissions of nitrogen oxides (NOx = NO + NO2) and CO2, high-resolution NO2 measurements from the TROPOspheric Monitoring Instrument (TROPOMI) are employed to map the global anthropogenic emissions at a global 0.1° scale. We construct the driving features from NO2 data and also incorporate gridded CO2/NOx emission ratios and NOx/NO2 conversion ratios as driving data to describe co-emissions. Both ratios are predicted using a long short-term memory (LSTM) neural network (with an R2 of 0.984 for the CO2/NOx emission ratio and an R2 of 0.980 for the NOx/NO2 conversion ratio). The data-driven model for estimating anthropogenic CO2 emissions is implemented by random forest regression (RFR) and trained using the Emissions Database for Global Atmospheric Research (EDGAR). The satellite-based anthropogenic CO2 emission dataset at a global 0.1° scale agrees well with the national CO2 emission inventories (an R2 of 0.998 with Global Carbon Budget (GCB) and an R2 of 0.996 with EDGAR) and consistent with city-level emission estimates from Carbon Monitor Cities (CMC) with the R2 of 0.824. This data-driven method based on satellite-observed NO2 provides a new perspective for fine-resolution anthropogenic CO2 emissions estimation.

An eco-friendly solution for construction and demolition waste: Recycled coarse aggregate with CO2 utilization.

Carbonation of recycled coarse aggregate (RCA) is an eco-friendly solution for the recycling of construction and demolition waste. This paper provides a comprehensive understanding of utilizing CO2 in RCA. The carbonation mechanism associated with CO2 treatment of RCA has been systematically summarized. The methods for CO2 treatment of RCA and the calculation of CO2 sequestration were discussed. Meanwhile, the efficiency of physical properties enhancement of carbonized RCA was analyzed. The microstructure, mechanical properties and durability improvement of recycled concrete containing carbonized RCA were reviewed. Additionally, the environmental benefits of carbonized RCA were provided through carbon footprint, carbon accounting and carbon intensity. Furthermore, the future perspectives of RCA with CO2 utilization were prospected.

Precisely Regulating Asymmetric Charge Distribution by Single-Atom Central Doped Ag-Based Series Clusters for Enhanced Photoreduction of CO2 to Alcohol Fuels.

High efficiently photocatalytic CO2 reduction (CO2RR) into liquid fuels in pure water system remains challenged. Iron polyphthalocyanine (FePPc) with strong light harvesting, unique Fe-N4 structure, abundant pores, and good stability could serve as a promising catalyst for CO2 photoreduction. To further improve the catalytic efficiency, herein, symmetry-breaking Fe sites are constructed by coupling with atomically precise M1Ag24 (M=Ag, Au, Pt) series clusters. Especially, the introduction of Pt1Ag24 causes the most asymmetric charge distribution of Fe in FePPc (followed by Au1Ag24 and Ag25), leading to the favorable CO2 adsorption and activation. In addition, Pt1Ag24-FePPc exhibits the most effective photogenerated carriers transfer and separation. As a result, Pt1Ag24-FePPc shows the methanol/ethanol yield of 48.55/32.97 µmol·gcat-1·h-1 in H2O-CO2 system under visible light irradiation, ~ 1.65/1.25-fold, 1.83/1.37-fold, and 3.6/1.61-fold higher than that of Au1Ag24-FePPc, Ag25-FePPc, and FePPc, respectively. This work provides a concept for precisely construction and regulation symmetry-breaking sites of cluster-based catalysts for effective CO2 conversion.

Pd-imidate@SBA-15: a multifunctional heterogeneous catalyst for the aqueous room temperature hydrogenation of CO2 to formic acid.

The incorporation of hydrophilic and basic sites from phosphotriazaadamantane and saccharine in a water-soluble Pd complex and the subsequent confinement into mesoporous silica support increases the activity and stability of the palladium catalytic species for the room-temperature aqueous hydrogenation of either bicarbonate or CO2 into formic acid. The use of low Pd loadings (<0.1mmolPd·g-1) of the well-dispersed complex on SBA-15 mesoporous silica allows performing the reaction under room temperature, and aqueous conditions, exhibiting TON of ca. 40-100, for the CO2 or bicarbonate hydrogenation, respectively, which is one order of magnitude higher than the homogeneous case, allowing the easy isolation and recycling of the solid catalyst.