CO2 Reduction Potential Research Articles

The diffusion of prefabrication technology and its potential for CO2 emissions reduction in China: A combined system dynamics and agent-based study

The building sector is one of the largest CO2 emitters. Prefabrication technology (PT) shows remarkable potential for reducing CO2 emissions during the material and construction phases of the building life cycle. However, the diffusion of PT in China is still in its infancy, and more targeted policies are necessary to accelerate the adoption of PT. This study proposes a combined system dynamics and agent-based modeling approach to include the technology adoption behavior of enterprises at the micro level, and the market effects and policies at the macro level. This approach provides a more comprehensive modeling approach and analysis for technology diffusion. Results show that the diffusion of PT has experienced three phases: (i) an initial phase that lasted until 2016, (ii) a mandatory adoption phase from 2016 to 2025, and (iii) a mandatory and market adoption phase that will last from 2025 to 2035 under appropriate policy mixes. A policy mix with moderate intensity is the most efficient in terms of balancing the policy effect and feasibility. The potential of CO2 reduction depends on both the diffusion rate of PT and the floor area of new buildings. Mandatory adoption is more effective than incentive-based policies in reducing CO2 emissions.

Enhanced Charge Transfer in Poly(Heptazine Imide) Synergistically Induced by Donor-Acceptor Motifs and Ohmic Junctions for Efficient Photocatalytic CO2 Reduction.

Poly(heptazine imide) (PHI) has received widely interest in the photocatalytic CO2 reduction due to its good crystallinity and complete in-plane structure. However, its poor photo-induced carrier separation and migration efficiency and insufficient active sites results in undesirable photocatalytic CO2 reduction performance. Herein, we designed and constructed a novel ohmic junction photocatalyst by integrating melamine edge-modified PHI (mel-PHI) with extended π-conjugated system with TiN (TiN/mel-PHI) for enhancing the photocatalytic CO2 reduction activity. Strikingly, the photocayalytic CO2 reduction yield of the optimal TiN/mel-PHI is 62.64 µmol·g-1·h-1, which is 5.6 and 2.8 times higher than PHI (11.26 µmol·g-1·h-1) and mel-PHI (22.32 µmol·g-1·h-1), respectively. The superior photocatalytic CO2 reduction activity is attributed not only to the formation of D-A structure by the introduction of melamine, which extends the π-conjugation system, alters the electronic structure of PHI, and accelerates the charge separation and migration, but also to the induced internal electric field by ohmic junction further enhances the charge separation and migration efficiency. Meanwhile, the synergistic effect of mel-PHI and TiN enriched the electron number of TiN, reducing the CO2 reduction potential. This work highlights the synergistic enhancement of charge transfer between D-A motifs and ohmic junctions, confirming their potential in optimizing photocatalysts.

Buildings in Hot Climate Zones—Quantification of Energy and CO2 Reduction Potential for Different Architecture and Building Services Measures

Reducing energy and associated greenhouse gas emissions in buildings is one of the key aspects of climate change on a global level. To put the building sector on a low carbon development path, policies and adequate financing play a crucial role in each region. In the global South, policies and regulations related to the decarbonization of the building stock are increasingly being implemented. For policy and decision makers, adequate data on the status quo of the building stock, as well as the quantification of energy reduction measures, are essential to make informed decisions on the building regulatory and funding framework. The objective of this study is to provide data-driven insights into the potential for energy and CO2 reduction in buildings across various hot climate zones in the Global South. A simulation-based approach was employed to model five different building types, ranging from residential homes to office buildings, under a variety of architectural and building services scenarios. The simulations were conducted using the dynamic building energy simulation tool EnergyPlus, which assessed the impact of various energy-saving measures under both current and projected future climate conditions. This study concludes that optimizing passive design features, such as improved windows, solar shading, and reflective surfaces, in conjunction with active systems like decentralized cooling units and renewable energy integration, can result in a notable reduction in energy demand and emissions. Our findings provide a robust basis for policymakers to develop targeted energy efficiency strategies for buildings in hot climate zones, which will play a crucial role in achieving climate goals in the Global South.

Enhanced photoelectrocatalytic CO2 reduction to CO via structure-induced carrier separation in coral-like CuBi2O4-Bi2O3

Significant carrier recombination has severely limited the development of the most potential photoelectrocatalytic CO2 reduction reaction (PEC-CO2 RR). Herein, coral-like CuBi2O4-Bi2O3 photocathodes are prepared using the strategy of the construction of heterojunction to improve the efficiency of carrier separation. As expected, its faradic efficiency of CO (FECO) at the lower potential (0.1 V vs. RHE) is 86.03 %, which is about 1.49 times higher than that of the original CuBi2O4 film. The increased catalytic activity of CuBi2O4-Bi2O3 can be attributed to the high surface area of the distinctive coral-like structure of Bi2O3, which enhances light absorption efficiency. Additionally, the higher degree of band bending in CuBi2O4-Bi2O3 and the built-in electric field can speed up the transport rate of electrons, slow down the recombination of photogenerated electrons with holes and extend the lifetime of photogenerated electrons, allowing electrons to continuously participate in the reaction. This study proposes a novel strategy to optimize the efficiency of photoelectrocatalytic CO2 reduction by CuBi2O4-based photocathodes.

Potentiostatic electrodeposition of copper, indium, and cadmium sulfides for CO2 electroreduction: A path toward sustainable hydrogen generation

This study focuses on the potentiostatic electrodeposition of copper indium and cadmium sulfide (CuS, In2S3, and CdS) thin films on copper substrates, aiming to develop efficient electrocatalysts for the electrochemical reduction of CO2 and sustainable hydrogen generation. Utilizing Cu Kα radiation for X-ray diffraction (XRD) analysis, the crystal structures of the electrodeposited films were confirmed, revealing well-defined crystalline phases. The films exhibited average particle sizes of 55.99 nm for CuS, 50.37 nm for In2S3, and 63.51 nm for CdS. Cyclic voltammetry and chronoamperometry were employed to optimize the deposition parameters, ensuring efficient nucleation and growth of the metal sulfide films. The electrochemical performance of the synthesized electrocatalysts was rigorously tested, demonstrating their potential for CO2 reduction under optimized conditions with the highest efficiency for CdS electrodes. Additionally, the electrodeposited CuS and CdS are of the p-type, and In2S3 is of the n-type semiconductor were studied and verified by the Mott–Schottky test. CuS, In2S3, and CdS were found to have donor and acceptor concentrations (ND) of 1.68 × 106, 1.44 × 105, and 8.9 × 105 cm3, respectively. The photoelectrochemical measurements of the electrodeposited metal sulfides were studied at ambient temperature and under illumination, providing higher photocurrent responses for CdS and demonstrating its strong potential as a photoelectrode material for CO2 reduction. This work underscores the significance of facile electrochemical synthesis methods in developing cost-effective and scalable electrocatalysts, paving the way for their integration into photoelectrochemical systems for green energy applications.

Evaluating the potential of different crop straw biochar to capture carbon dioxide and increase the growth of Zea mays L.

The roles of biochar in capturing CO2 and ensuring food security are intertwined. Thus, a comprehensive understanding of these roles is crucial for optimizing the environmental benefits of biochar. Six crop straws: non-legumes (rice straw-RS, maize straw-MS, and wheat straw-WS), and legumes (chickpea straw-CS, mustard straw-MTS, and peanut straw-PS), were used to prepare biochar (RB, MB, WB, CB, MTB, and PB, respectively) at 700 °C and their ability to capture CO2, improve soil fertility, and enhance maize plant growth was evaluated. Our results revealed that the CO2 reduction potential (CRP) differed significantly, with CB being more efficient in retaining CO2. The CRP showed a significant polynomic relationship with ΔpH (R2 = 0.9646) and Δexchangeable acidity (R2 = 0.6356) but not with Δsoil organic carbon (R2 = 0.4181). Due to the differences in their physicochemical properties, straws and biochar had significantly different effects on soil pH, exchangeable acidity, nutrient uptake, maize growth, and maize biomass accumulation. Also, the N uptake potential of maize plants grown in biochar-amended soils was significantly larger than that of the respective straw. This significant difference in nutrient uptake between biochar and straw treatments was also observed for K, Ca, and Mg, and corroborates the significant differences recorded in plant growth parameters. Thus, converting crop residues to biochar sequesters carbon through the storage of captured CO2 thereby mitigating climate change. Also, by incorporating biochar in soil, soil acidity decreases, soil fertility increases, and the growth of maize plants improves. Nevertheless, it is important to carefully select biochar feedstock so as to achieve the optimal effects of carbon sequestration and soil fertility improvement when applied to agricultural soils.Graphical

Glycine modified copper promotes CO2 electroreduction to multi-carbon products: a computational study.

Molecular modification strategy exhibits great potential for electrocatalytic CO2 reduction. Here, DFT calculations were applied to study the mechanism of CO2 electroreduction on glycine modified copper. The results indicate that the interaction between the modified molecule and the intermediate could change the reaction energy of CO2 electroreduction.

Domestication of halotolerant methanogens for energy-efficient microbial electrosynthesis of methane from CO2

Microbial electrosynthesis (MES) has great potential for CO2 reduction and renewable energy storage. However, high energy consumption and investment costs constrained the practical application of MES. Here, the domestication of halotolerant methanogens was proposed to improve the energy efficiency of MES, and methane metabolism under low and high Na+ concentrations was explored by metagenomic analysis. The Na+ concentration of the catholyte was increased from 4.07 g·L-1 to 23.01 g·L-1, and the reactor maintained great performance after initial inhibition. High-salinity catholyte improved the energy efficiency to 47% and reduced the cathode voltage consumption. Increasing Na+ concentration, microorganisms resisted damage by secreting more extracellular polymers, and maintained methane production through community evolution. The relative abundance of Euryarchaeota increased from 50% to 80%. Methanobrevibacter and Methanobacterium were dominant genera at Na+ of 23.01 g·L-1. Incorporating metagenomic analysis, the methane metabolism at the initial period (Na+:4.07 g·L-1) included a CO2-reduction pathway and acetoclastic pathway. However, when Na+ concentration increased to 23.01 g·L-1, the CO2-reduction pathway with 4Fe–4S ferredoxin and common pathways was significantly enhanced, in addition, the acetyl metabolism pathway using CO2 as substrate was also enhanced. Overall, methane metabolism was enhanced, and the metabolic pathways changed with increasing Na⁺ concentration.

The Steelmaking Transformation Process and Its Consequences for Slag Utilization

The main challenge of the European steel industry for the next decade is the steel production transformation process. Many steel producers aim to avoid their CO2 emissions by substituting the CO2‐intensive blast furnace/basic oxygen furnace route by a gas‐based direct reduced iron (DRI) process combined with an electric smelting process. Thus, the well‐known latent hydraulic granulated blast furnace slag (GBS) will vanish step by step. For more than 140 years, this slag has been used as a supplementary cementitious material due to its clinker reduction potential and from there its CO2 reduction potential for the cement and concrete production. Moreover, slag cements offer some special technical advantages. Whereas the solid‐state DRI process itself does not generate any slag, the different electric smelting processes will produce liquid steel or “electric” pig iron, respectively, together with very different types of slags. However, specific slag/metal ratios, resulting slag volumes, chemical and mineralogical composition, and physical properties of the new slags are yet unknown. Therefore, their cementitious and environmental properties are also still unknown. Different current and scheduled projects aim mainly to enable the different types of new slags to substitute GBS to continue the successful cross‐industrial cooperation between steel and cement industry.

Hetero-Bimetallic Paddlewheel Complexes for Enhanced CO2 Reduction Selectivity: A First Principles Study

The reduction of carbon dioxide (CO2) into value-added feedstock materials, fine chemicals, and fuels represents a crucial approach for meeting contemporary chemical demands while reducing dependence on petrochemical sources. Optimizing catalysts for the CO2 reduction reaction can entail employing first principles methods to identify catalysts possessing desirable attributes, including the ability to form diverse products, selectively form few products, or exhibit favorable reaction kinetics. In this study, we investigate the CO2 reduction reaction on bimetallic Cu paddlewheel complexes, aiming to understand the impact metal substitution with Mn, Co, or Ni has on bimetallic paddlewheel metal-organic frameworks (MOFs). Substituting one of the Cu sites of the paddlewheel complex with Mn results in a more catalytically active Cu center, poised to produce substantial quantities of formic acid (HCOOH) and minor quantities of methane (CH4) with a suppressed production of C2 products such as ethanol (CH3CH2OH) or ethylene (C2H4). Moreover, the presence of Mn significantly reduces the limiting potential for CO2 reduction from 2.22 eV on the homo-bimetallic Cu paddlewheel complex to 1.19 eV, thereby necessitating a smaller applied potential. Conversely, within the Co-substituted paddlewheel complex, the Co site emerges as the primary catalytic center, selectively yielding CH4 as the sole reduced CO2 product, with a limiting potential of 1.22 eV. Notably, the Co site faces substantial competition from H2 production, attributed to a lower limiting potential of 0.81 eV for hydrogen reduction. Our examination of the Cu-Ni paddlewheel complex, featuring a Ni substituent site, reveals two catalytically active centers, each promoting distinct reductive processes. Both the Ni and Cu sites exhibit a propensity for HCOOH formation, with the Ni site favoring further reduction to CH4, while the Cu site directs the reaction towards methanol (CH3OH) production. The significance of this study lies in its potential to inform and streamline future experimental efforts, facilitating the synthesis and evaluation of novel catalysts with superior capabilities for CO2 reduction.

Oxidative and Reductive Manipulation of C1 Resources by Bio-Inspired Molecular Catalysts to Produce Value-Added Chemicals.

ConspectusTo tackle the energy and environmental concerns the world faces, much attention is given to catalytic reactions converting methane (CH4) and carbon dioxide (CO2) as abundant C1 resources into value-added chemicals with high efficiency and selectivity. In the oxidative conversion of CH4 to methanol, it is necessary to solve the requirement of strong oxidants due to the large bond-dissociation energy (BDE) of the C-H bonds in methane and achieve suppression of overoxidation due to the smaller BDE of the C-H bond in methanol as the product. On the other hand, to efficiently perform CO2 reduction, proton-coupled electron transfer (PCET) processes are required since the reduction potential of CO2 becomes positive by using proton-coupled processes; however, under the acidic conditions required for PCET, hydrogen evolution by the reduction of protons becomes competitive with CO2 reduction. Thus, it is indispensable to develop efficient catalysts for selective CO2 reduction. Recently, we have developed efficient catalytic reactions toward the alleviation of the concerns mentioned above. Concerning CH4 oxidation, inspired by metalloenzymes that oxidize hydrophobic organic substrates, a hydrophobic second coordination sphere (SCS) was introduced to an FeII complex bearing a pentadentate N-heterocyclic carbene ligand, and the FeII complex was used as a catalyst for CH4 oxidation in aqueous media. Consequently, CH4 was efficiently and selectively oxidized to methanol with 83% selectivity and a turnover number of 500. In contrast, when methanol was used as a substrate for catalytic oxidation by the FeII complex, oxidation products were obtained in a negligible yield, which was comparable to that of the control experiment without the catalyst. Therefore, the hydrophobic SCS of the FeII complex can capture only hydrophobic substrates such as CH4 and release hydrophilic products such as methanol to the aqueous medium for suppressing overoxidation ("catch-and-release" mechanism). On the other hand, for photocatalytic CO2 reduction, we have developed NiII complexes with N2S2-chelating ligands as catalysts, which have been inspired by carbon monoxide dehydrogenase, and have also introduced a binding site of Lewis-acidic metal ions to the SCS of the Ni complex. When Mg2+ was applied as a moderate Lewis acid, a Mg2+-bound Ni catalyst allowed us to achieve remarkable enhancement of the photocatalytic CO2 reduction to afford CO as the product with over 99% selectivity and a quantum yield of 11.4%. Divalent metal ions besides Mg2+ also showed similar positive impacts on photocatalytic CO2 reduction, whereas monovalent metal ions exhibited almost no effects and trivalent metal ions exclusively promoted hydrogen evolution. In this Account, we highlight our recent progress in the catalytic manipulations of CH4 and CO2 as C1 resources.

The Structure of Carbon Dioxide at the Air-Water Interface and its Chemical Implications.

The efficient reduction of CO2 into valuable products is a challenging task in an international context marked by the climate change crisis and the need to move away from fossil fuels. Recently, the use of water microdroplets has emerged as an interesting reaction media where many redox processes which do not occur in conventional solutions take place spontaneously. Indeed, several experimental studies in microdroplets have already been devoted to study the reduction of CO2 with promising results. The increased reactivity in microdroplets is thought to be linked to unique electrostatic solvation effects at the air-water interface. In the present work, we report a theoretical investigation on this issue for CO2 using first-principles molecular dynamics simulations. We show that CO2 is stabilized at the interface, where it can accumulate, and that compared to bulk water solution, its electron capture ability is larger. Our results suggest that reduction of CO2 might be easier in interface-rich systems such as water microdroplets, which is in line with early experimental data and indicate directions for future laboratory studies. The effect of other relevant factors which could play a role in CO2 reduction potential is discussed.

Comprehensive analysis of carbon emission reduction technologies (CRTs) in China's coal-fired power sector: A bottom-up approach

Carbon dioxide (CO2) reduction technologies (CRTs) in the coal-fired power sector play an imperative role in the mitigation of environmental challenges and reducing CO2 emissions to help achieve the 2 °C target. However, a compelling necessity persists for a unified framework that can effectively and accurately estimate the costs and potentials associated with CRTs, arising from the diversity of technologies and unit types. Therefore, this study employs a bottom-up approach to analyze the costs and potential of 25 advanced CRTs in the coal-fired power sector, excluding CO2 capture, utilization and storage (CCUS), across 19 types of coal-fired power units. This analysis amalgamates the CO2 reduction supply curve (CRSC) approach with levelized cost of CO2 reduction (LCOC) and a broken-even analysis which could reflect the sector's average carbon reduction cost. The outcomes reveal the following key insights: (1) These technologies collectively harbor a substantial CO2 conservation potential amounting to 925.61 Mt CO2, with a broken-even price of CNY 410.1/tCO2. This reduction could potentially lower 20%–25 % of CO2 emissions in China's power system in 2022, highlighting the crucial role of CRTs in achieving a low-carbon transition and national climate targets; (2)Steam turbine flow path retrofit (T8) not only offers a relatively high CO2 reduction potential (>60 Mt CO2), but also features a low cost (<CNY 150/tCO2) and high profit (>CNY 0.85/MWh). Prioritizing the development of this technology can significantly accelerate the low-carbon transition of coal power; (3) Carbon price have a paramount influence on the cost-effectiveness of CRTs and driving their adoption.

Direct formation of copper nanoparticles from atoms at graphitic step edges lowers overpotential and improves selectivity of electrocatalytic CO2 reduction

A key strategy for minimizing our reliance on precious metals is to increase the fraction of surface atoms and improve the metal-support interface. In this work, we employ a solvent/ligand/counterion-free method to deposit copper in the atomic form directly onto a nanotextured surface of graphitized carbon nanofibers (GNFs). Our results demonstrate that under these conditions, copper atoms coalesce into nanoparticles securely anchored to the graphitic step edges, limiting their growth to 2–5 nm. The resultant hybrid Cu/GNF material displays high selectivity in the CO2 reduction reaction (CO2RR) for formate production with a faradaic efficiency of ~94% at -0.38 V vs RHE and a high turnover frequency of 2.78 × 106 h-1. The Cu nanoparticles adhered to the graphitic step edges significantly enhance electron transfer to CO2. Long-term CO2RR tests coupled with atomic-scale elucidation of changes in Cu/GNF reveal nanoparticles coarsening, and a simultaneous increase in the fraction of single Cu atoms. These changes in the catalyst structure make the onset of the CO2 reduction potential more negative, leading to less formate production at -0.38 V vs RHE, correlating with a less efficient competition of CO2 with H2O for adsorption on single Cu atoms on the graphitic surfaces, revealed by density functional theory calculations.

Acceleration of Photoinduced Electron Transfer by Modulating Electronegativity of Substituents in Stable Zr-Metal-Organic Frameworks to Boost Photocatalytic CO2 Reduction.

Photoreduction of CO2 with water into chemical feedstocks of fuels provides a green way to help solve both the energy crisis and carbon emission issues. Metal-organic frameworks (MOFs) show great potential for CO2 photoreduction. However, poor water stability and sluggish charge transfer could limit their application. Herein, three water-stable MOFs functionalized with electron-donating methyl groups and/or electron-withdrawing trifluoromethyl groups are obtained for the CO2 photoreduction. Compared with UiO-67-o-CF3-CH3 and UiO-67-o-(CF3)2, UiO-67-o-(CH3)2 achieves excellent performance with an average CO generation rate of 178.0 μmol g-1 h-1 without using any organic solvent or sacrificial reagent. The superior photocatalytic activity of UiO-67-o-(CH3)2 is attributed to the fact that compared with trifluoromethyl groups, methyl groups could not only elevate CO2 adsorption capacity and reduction potential but also promote photoinduced charge separation and migration. These are evidenced by gas physisorption, photoluminescence, time-resolved photoluminescence, electrochemical impedance spectroscopy, transient photocurrent characteristics, and density functional theory calculations. The possible working mechanisms of electron-donating methyl groups are also proposed. Moreover, UiO-67-o-(CH3)2 demonstrates excellent reusability for the CO2 reduction. Based on these results, it could be affirmed that the strategy of modulating substituent electronegativity could provide guidance for designing highly efficient photocatalysts.

Potential and Environmental Benefits of Biochar Utilization for Coal/Coke Substitution in the Steel Industry

The metallurgical sector is one of the most emission- and energy-intensive industries. The possibility of using fossil carbon substitutes has been investigated to reduce the environmental impact of the steelmaking sector. Among others, biochar emerged as a promising fossil coal/coke substitute. We conducted a literature review on biochar use in the metallurgical sector and its potential environmental benefits. The possibility for biochar as a coal/coke substitute is influenced by the source of biochar production and the process within which it can be used. In general, it has been observed that substitution of biochar ranging from a minimum of 5% to a maximum of 50% (mostly around 20–25%) is possible without affecting, or in some cases improving, the process, in coke making, iron sintering, blast furnaces and electric furnaces application. In some studies, the potential CO2 reduction due to biochar use was estimated, ranging from 5% to about 50%. Despite there still being an area of further investigation, biochar appeared as a promising resource with a variety of uses in the metallurgical sector, contributing to the lowering of the environmental impact of the sector.

Photoelectrocatalytic Reduction of CO2 to CO via Cu2O/C/PTFE Nanowires Photocathodes

AbstractThe consumption of fossil fuels releases large amounts of carbon dioxide (CO2) in the atmosphere, causing a serious greenhouse effect. Photoelectrochemical (PEC) reduction of CO2 to chemical fuels is an effective way to alleviate the current energy and environmental crisis. However, it is still difficult to rationally design efficient PEC CO2 reduction photocathodes. Cuprous oxide (Cu2O) is a promising photocathode material, but its surface is susceptible to the accumulation of photogenerated electrons leading to corrosion and activity reduction, and is accompanied by hydrogen evolution reaction (HER), both of which lead to the overall low conversion efficiency of CO2 reduction by Cu2O. In this study, the PEC CO2 conversion efficiency was improved by the synergistic effect of the C electron transport layer to accelerate the electron transfer to alleviate the Cu2O corrosion problem and the polytetrafluoroethylene (PTFE) hydrophobic layer to inhibit the HER. The test showed that the CO yield of Cu2O/C/PTFE at the optimum potential (−0.7 V vs. RHE) was 54.6 μmol cm−2 h−1, which was 3.2 times higher than that of pure Cu2O. This study provides a facile strategy for constructing an efficient photocathode with great potential for CO2 reduction.

Parametric investigation of the effects of variables controlling thermal characteristics during continuous and high-speed cold stamping processes with active cooling structures

Knowledge of the thermal phenomena that occur during stamping is important for improving the design and performance of stamping die thermal structures. A new mathematical full-scale model for energy and carbon flows is established based on operational data from a cold stamping production line in China. Moreover, numerical simulations of the thermal-fluid–solid coupling field for a cooling medium in an asymmetrically heated rectangular channel with high heat flux and strong wall superheating are carried out with a suitable CFD solver. The results are discussed in detail and compared with theoretical calculations, and the deviation of the surface heat transfer coefficient is ± 11.9 %. Emphasis is placed on parametric effects of variables controlling thermal characteristics on cold stamping with an active cooling structure. The effects of heat flux, and ambient temperature on temperature rise, pressure drops, and heat transfer coefficients are limited less than 7 °C, 167 Pa and 45.11 % under specific operating conditions, respectively. While the heat transfer coefficient and pressure drops are increased hundreds of times with inlet velocity. The fluid cooling performance, threshold value, and approaches for heat transfer enhancement are obtained. Finally, the CO2 emissions rates is assessed as approximately 1.8 g per piece associated with stamping operations, as well as major contributors, CO2 reduction potential, and economic impacts. Negative energy consumption can be achieved with active cooling. These results can help to improve production quality in the future application and provide theoretical support for determining the causes of metal sheet tensile cracking accidents.

Scenario Analysis of CO2 Reduction Potentials from a Carbon Neutral Perspective

As a major emitter of CO2, China needs to take responsibility for slowing down global warming. In this paper, the potential carbon emission intensity of provinces is firstly calculated using the non-radial directional distance function under the group- and meta-frontier techniques, and then six scenarios based on two factors (economic development and carbon intensity) are set up to estimate the emission reduction potential of China and each province. Considering the goal of carbon neutrality, the calculation of CO2 emission reduction potential quantifies the amount of emissions that can be reduced and the amount of emissions that should be balanced. Additionally, the degree of difficulty in achieving abatement potential is also calculated. The findings are as follows: First, assuming that the economic growth rate is reduced to 4.4% (achieving the second “100-year goal”) and each province adopts the most advanced low-carbon technologies, China could reduce carbon emissions by 5970.56 Mt compared to 2019 levels. To achieve net-zero emissions, the remaining 3824.2 Mt of carbon emissions should be removed by carbon reduction technologies. Second, the effect of slowing down economic growth and decreasing carbon intensity varies greatly among provinces. Hebei and Shandong should be prioritized as they have the greatest potential for emission reductions under both scenarios. Third, it is more difficult for Beijing, Shanghai, Hubei, Hunan, Inner Mongolia Autonomous Region, Chongqing, and Sichuan to achieve the abatement potential and they require more effort to reduce the same amount of carbon emissions compared to other provinces. The study provides a reference for achieving carbon neutrality and helps provinces to develop differentiated emission reduction strategies.

Post-synthetic Metalation on the Ionic TiO2 Surface to Enhance Metal-CO2 Interaction During Photochemical CO2 Reduction.

During the photochemical CO2 reduction reaction, CO2 adsorption on the catalyst's surface is a crucial step where the binding mode of the [metal-CO2] adduct directs the product selectivity and efficiency. Herein, an ionic TiO2 nanostructure stabilized by polyoxometalates (POM), ([POM]x@TiO2), is prepared and the sodium counter ions present on the surface to balance the POMs' charge are replaced with copper(II) ions, (Cux[POM]@TiO2). The microscopic and spectroscopic studies affirm the copper exchange without altering the TiO2 core and weak coordination of copper (II) ions to the POMs' surface. Band structure analysis suggests the photo-harvesting efficiency of the TiO2 core with the conduction band edge higher than the reduction potential of CuII/I and multi-electron CO2 reduction potentials. Photochemical CO2 reduction with Cux[POM]@TiO2 results in 30 μmol gcat. -1 CO (79 %) and 8 μmol gcat -1 of CH4 (21 %). Quasi-in-situ Raman study provides evidence in support of CO2 adsorption on the Cux[POM]@TiO2 surface. 13C and D2O labeling studies affirm the {Cu-[CO2]-} adduct formation. Despite the photo-harvesting ability of Nax[POM]@TiO2 itself, the poor CO2 adsorption ability of sodium ions highlights the crucial role of copper ion CO2 photo-reduction. Characterization of the {M-[η2-CO2]-} species via surface tuning validates the CO2 activation and photochemical reduction pathway proposed earlier.