Preferentially selective extraction of lithium from spent LiCoO_(2)cathodes by medium-temperature carbon reduction roasting

Lithium recovery from spent lithium-ion batteries(LIBs)have attracted extensive attention due to the skyrocketing price of lithium.The medium-temperature carbon reduction roasting was proposed to preferential selective extraction of lithium from spent Li-CoO_(2)(LCO)cathodes to overcome the incomplete recovery and loss of lithium during the recycling process.The LCO layered structure was destroyed and lithium was completely converted into water-soluble Li2CO_(3)under a suitable temperature to control the reduced state of the cobalt oxide.The Co metal agglomerates generated during medium-temperature carbon reduction roasting were broken by wet grinding and ultrasonic crushing to release the entrained lithium.The results showed that 99.10%of the whole lithium could be recovered as Li2CO_(3)with a purity of 99.55%.This work provided a new perspective on the preferentially selective extraction of lithium from spent lithium batteries.

Investigation into the Methodology and Implementation of Life Cycle Engineering under China’s Carbon Reduction Target in the Process Industry

The industrial sector is the primary source of carbon emissions in China.In pursuit of meeting its carbon reduction targets,China aims to promote resource consumption sustainability,reduce energy consumption,and achieve carbon neutrality within its processing industries.An effective strategy to promote energy savings and carbon reduction throughout the life cycle of materials is by applying life cycle engineering technology.This strategy aims to attain an optimal solution for material performance,resource consumption,and environmental impact.In this study,five types of technologies were considered:raw material replacement,process reengineering,fuel replacement,energy recycling and reutilization,and material recycling and reutilization.The meaning,methodology,and development status of life cycle engineering technology abroad and domestically are discussed in detail.A multidimensional analysis of ecological design was conducted from the perspectives of resource and energy consumption,carbon emissions,product performance,and recycling of secondary resources in a manufacturing process.This coupled with an integrated method to analyze carbon emissions in the entire life cycle of a material process industry was applied to the nonferrous industry,as an example.The results provide effective ideas and solutions for achieving low or zero carbon emission production in the Chinese industry as recycled aluminum and primary aluminum based on advanced technologies had reduced resource consumption and emissions as compared to primary aluminum production.

Porously Reduced 2-Dimensional Bi_(2)O_(2)CO_(3) Petals for Strain-Mediated Electrochemical CO_(2) Reduction to HCOOH

Here we introduce bismuth-based catalysts for the efficient electrochemical reduction of CO_(2)to formic acid(HCOOH),which are composed of petal-shaped Bi_(2)O_(2)CO_(3)(BOC)that spontaneously formed from Bi thin film in aqueous carbonate solution at room temperature.During the electrochemical reduction process,the BOC petals transform to reduced BOC(R-BOC)consisting of individual BOC and Bi domains.Lattice mismatch between both domains induces biaxial strain at the interfaces.Density functional theory calculations suggest that the tensile strain on the Bi domain stabilizes the*OCHO intermediate,reducing the thermodynamic barrier toward CO_(2)conversion to HCOOH.Together with the thermodynamic benefit and the unique nanoporous petal-shaped morphology,R-BOC petals have a superior Faradaic efficiency of 95.9%at-0.8 V_(RHE)for the electrochemical conversion of CO_(2)to HCOOH.This work demonstrates that the spontaneously formed binary phases with desirable lattice strain can increase the activity of bismuth catalysts to the CO_(2)reduction reaction;such a strategy can be applicable in design of various electrocatalysts.

Cu single-atom electrocatalyst on nitrogen-containing graphdiyne for CO_(2) electroreduction to CH_(4)

Developing Cu single-atom catalysts(SACs)with well-defined active sites is highly desirable for producing CH4 in the electrochemical CO_(2) reduction reaction and understanding the structure-property relationship.Herein,a new graphdiyne analogue with uniformly distributed N_(2)-bidentate(note that N_(2)-bidentate site=N^N-bidentate site;N_(2)≠dinitrogen gas in this work)sites are synthesized.Due to the strong interaction between Cu and the N_(2)-bidentate site,a Cu SAC with isolated undercoordinated Cu-N_(2) sites(Cu1.0/N_(2)-GDY)is obtained,with the Cu loading of 1.0 wt%.Cu1.0/N_(2)-GDY exhibits the highest Faradaic efficiency(FE)of 80.6% for CH_(4) in electrocatalytic reduction of CO_(2) at-0.96 V vs.RHE,and the partial current density of CH_(4) is 160 mA cm^(-2).The selectivity for CH_(4) is maintained above 70% when the total current density is 100 to 300 mA cm^(-2).More remarkably,the Cu1.0/N_(2)-GDY achieves a mass activity of 53.2 A/mgCu toward CH4 under-1.18 V vs.RHE.In situ electrochemical spectroscopic studies reveal that undercoordinated Cu-N_(2) sites are more favorable in generating key ^(*)COOH and ^(*)CHO intermediate than Cu nanoparticle counterparts.This work provides an effective pathway to produce SACs with undercoordinated Metal-N_(2) sites toward efficient electrocatalysis.

Central environmental protection inspection and carbon emission reduction: A tripartite evolutionary game model from the perspective of carbon neutrality

Since the carbon neutrality target was proposed,many countries have been facing severe challenges to carbon emission reduction sustainably.This study is conducted using a tripartite evolutionary game model to explore the impact of the central environmental protection inspection(CEPI)on driving carbon emission reduction,and to study what factors influence the strategic choices of each party and how they interact with each other.The research results suggest that local governments and manufacturing enterprises would choose strategies that are beneficial to carbon reduction when CEPI increases.When the initial willingness of all parties increases 20%,50%—80%,the time spent for the whole system to achieve stability decreases from 100%,60%—30%.The evolutionary result of“thorough inspection,regulation implementation,low-carbon management”is the best strategy for the tripartite evolutionary game.Moreover,the smaller the cost and the larger the benefit,the greater the likelihood of the three-party game stability strategy appears.This study has important guiding significance for other developing countries to promote carbon emission reduction by environmental policy.

Single atom Cu-N-C catalysts for the electro-reduction of CO_(2) to CO assessed by rotating ring-disc electrode

The electrochemical CO_(2) reduction reaction(CO_(2)RR) to controllable chemicals is considered as a promising pathway to store intermittent renewable energy. Herein, a set of catalysts based on copper-nitrogendoped carbon xerogel(Cu-N-C) are successfully developed varying the copper amount and the nature of the copper precursor, for the efficient CO_(2)RR. The electrocatalytic performance of Cu-N-C materials is assessed by a rotating ring-disc electrode(RRDE), technique still rarely explored for CO_(2)RR. For comparison, products are also characterized by online gas chromatography in a H-cell. The as-synthesized Cu-NC catalysts are found to be active and highly CO selective at low overpotentials(from -0.6 to -0.8 V vs.RHE) in 0.1 M KHCO_(3), while H_(2) from the competitive water reduction appears at larger overpotentials(-0.9 V vs. RHE). The optimum copper acetate-derived catalyst containing Cu-N_(4) moieties exhibits a CO_(2)-to-CO turnover frequency of 997 h^(-1) at -0.9 V vs. RHE with a H_(2)/CO ratio of 1.8. These results demonstrate that RRDE configuration can be used as a feasible approach for identifying electrolysis products from CO_(2)RR.

A Cu-Pd alloy catalyst with partial phase separation for the electrochemical CO_(2) reduction reaction

Cu catalysts can convert CO_(2) through an electrochemical reduction reaction into a variety of useful carbon-based products.However,this capability provides an obstacle to increasing the selectivity for a single product.Herein,we report a simple fabrication method for a Cu-Pd alloy catalyst for use in a membrane electrode assembly(MEA)-based CO_(2) electrolyzer for the electrochemical CO_(2) reduction reaction(ECRR)with high selectivity for CO production.When the composition of the Cu-Pd alloy catalyst was fabricated at 6:4,the selectivity for CO increased and the production of multi-carbon compounds and hydrogen is suppressed.Introducing a Cu-Pd alloy catalyst with 6:4 ratio as the cathode of the MEAbased CO_(2) electrolyzer showed a CO faradaic efficiency of 92.8%at 2.4 V_(cell).We assumed that these results contributed from the crystal planes on the surface of the Cu-Pd alloy.The phases of the Cu-Pd alloy catalyst were partially separated through annealing to fabricate a catalyst with high selectivity for CO at low voltage and C_(2)H_4 at high voltage.The results of CO-stripping testing confirmed that when Cu partially separates from the lattice of the Cu-Pd alloy,the desorption of~*CO is suppressed,suggesting that C-C coupling reaction is favored.

Crystallographically vacancy‐induced MOF nanosheet as rational single‐atom support for accelerating CO_(2) electroreduction to CO

To attain a circular carbon economy and resolve CO_(2) electroreduction technology obstacles,single‐atom catalysts(SACs)have emerged as a logical option for electrocatalysis because of their extraordinary catalytic activity.Among SACs,metal–organic frameworks(MOFs)have been recognized as promising support materials because of their exceptional ability to prevent metal aggregation.This study shows that atomically dispersed Ni single atoms on a precisely engineered MOF nanosheet display a high Faradaic efficiency of approximately 100% for CO formation in H‐cell and three‐compartment microfluidic flow‐cell reactors and an excellent turnover frequency of 23,699 h^(−1),validating their intrinsic catalytic potential.These results suggest that crystallographic variations affect the abundant vacancy sites on the MOF nanosheets,which are linked to the evaporation of Zn‐containing organic linkers during pyrolysis.Furthermore,using X‐ray absorption spectroscopy and density functional theory calculations,a comprehensive investigation of the unsaturated atomic coordination environments and the underlying mechanism involving CO^(*) preadsorbed sites as initial states was possible and provided valuable insights.

Facet effects on bimetallic ZnSn hydroxide microcrystals for selective electrochemical CO_(2)reduction

Employing crystal facets to regulate the catalytic properties in electrocatalytic carbon dioxide reduction reaction(eCO_(2)RR)has been well demonstrated on electrocatalysts containing single metals but rarely explored for bimetallic systems.Here,we synthesize ZnSn(OH)_(6)(ZSO)microcrystals(MCs)with distinct facets and investigate the facet effects in eCO_(2)RR.Electrochemical studies and in situ Fourier Transform Infrared Spectroscopy(in situ-FTIR)reveal that ZSO MCs produce mainly C1 products of HCOOH and CO.The{111}facet of the ZSO MCS exhibits higher selectivity and faradaic efficiency(FE)than that of the{100}facet over a wide range of potentials(-0.9 V∼-1.3 V versus RHE).Density Functional Theory(DFT)calculations elucidate that the{111}facet is favorable to the adsorption/activation of CO_(2)molecules,the formation of intermediate in the rate-determining step,and the desorption of C1 products of CO and HCOOH molecules.

Urban Landscaping Design and Carbon Reduction Planning Countermeasures

As the most significant green ecological resource in densely populated and economically developed areas,urban landscaping plays a pivotal role in carbon sink value and multiple ecosystem service functions.It is a crucial element in the advancement of green and low-carbon initiatives in China’s major cities and the realization of a carbon-neutral vision.By analyzing the relationship between carbon emission reduction and urban landscaping,the paper sorts out and summarizes the basic principles of urban landscaping design,proposes the role of landscape design in urban landscaping,and plans countermeasures for carbon reduction in urban landscaping,with a view to optimizing the construction and management of urban landscaping.

Reduction effect of carbon emission and optimisation path of green finance

Under the background of"dual-carbon",green finance is an important way to promote carbon emission reduction and realize the development of a low-carbon economy.Using provincial panel data from 2000 to 2020,this paper constructs a basic regression model to study the"carbon reduction"effect,mechanism of action,and heterogeneity of green finance.The study finds that:the development of green finance significantly inhibits carbon emissions and has an obvious"carbon reduction"effect;green technology innovation has a mediating effect on the carbon emission reduction effect of green finance;in regions with a high level of economic development or a high degree of marketization,the"carbon reduction"effect of green finance is significant.

NO reduction by CO over TiO_2-γ-Al_2O_3 supported In/Ag catalyst under lean burn conditions

TiO2/γ-Al2O3 supported In/Ag catalysts were prepared by impregnation method,and investigated for NO reduction with CO as the reducing agent under lean burn conditions.The microscopic structure and surface properties of the catalysts were studied by N2 adsorption-desorption,X-ray diffraction,transmission electron microscopy,X-ray photoelectron spectroscopy,ultraviolet-visible spectroscopy,H2 temperature-programmed reduction and Fourier transform infrared spectroscopy.TiO2/γ-Al2O3 supported In/Ag is a good catalyst for the reduction of NO to N2.It displayed high dispersion,large amounts of surface active components and high NO adsorption capacity,which gave good catalytic performance and stability for the reduction of NO with CO under lean burn conditions.The silver species stabilized and improved the dispersion of the indium species.The introduction of TiO2 into the γ-Al2O3 support promoted NO adsorption and improved the dispersion of the indium species and silver species.

Efficient electrocatalytic reduction of carbon dioxide to ethylene on copper–antimony bimetallic alloy catalyst

The exploration of efficient electrocatalysts for the reduction of CO2 to C2H4 is of significant importance but is also a challenging subject.Cu-based bimetallic catalysts are extremely promising for efficient CO2 reduction.In this work,we synthesize a series of porous bimetallic Cu–Sb alloys with different compositions for the catalytic reduction of CO2 to C2H4.It is demonstrated that the alloy catalysts are much more efficient than the pure Cu catalyst.The performance of the alloy catalysts depended strongly on the composition.Further,the alloy with a Cu:Sb ratio of 10:1 yielded the best results;it exhibited a high C2H4 Faradaic efficiency of 49.7%and a high current density of 28.5 mA cm?2 at?1.19 V vs.a reversible hydrogen electrode(RHE)in 0.1 M KCl solution.To the best of our knowledge,the electrocatalytic reduction of CO2 to C2H4 using Cu–Sb alloys as catalysts has not been reported.The excellent performance of the porous alloy catalyst is attributed to its favorable electronic configuration,large surface area,high CO2 adsorption rate,and fast charge transfer rate.

Integration of ultrafine CuO nanoparticles with two‐dimensional MOFs for enhanced electrochemicgal CO_(2) reduction to ethylene

To facilitate the electrochemical CO_(2) reduction(ECR)to fuels and valuable chemicals,the development of active,low cost,and selective catalysts is crucial.We report a novel ECR catalyst consisting of CuO nanoparticles with sizes ranging from 1.4 to 3.3 nm anchored on Cu metal‐organic framework(Cu‐MOF)nanosheets obtained through a one‐step facile solvothermal method.The nanocomposites provide multiple sites for efficient ambient ECR,delivering an average C_(2)H_(4) faradaic efficiency(FE)of~50.0%at–1.1 V(referred to the reversible hydrogen electrode)in 0.1 mol/L aqueous KHCO_(3) using a two‐compartment cell,in stark contrast to a C_(2)H_(4) FE of 25.5%and 37.6%over individual CuO and Cu‐MOF respectively,also surpassing most newly reported Cu‐based materials under similar cathodic voltages.The C_(2)H_(4) FE remains at over 45.0%even after 10.0 h of successive polarization.Also,a~7.0 mA cm^(–2) C_(2)H_(4) partial geometric current density and 27.7%half‐cell C_(2)H_(4) power conversion efficiency are achieved.The good electrocatalytic performance can be attributed to the interface between CuO and Cu‐MOF,with accessible metallic moieties and the unique two‐dimensional structure of the Cu‐MOF enhancing the adsorption and activation of CO_(2) molecules.This finding offers a simple avenue to upgrading CO_(2) to value‐added hydrocarbons by rational design of MOF‐based composites.

Enhanced CO_(2)electroreduction to ethylene via strong metal-support interaction

The CuO/CeO_(2) composites with strong metal-support interaction were synthesised,which can efficiently electroreduct CO_(2)to C(2)H_(4).The Faradaic efficiency(FE)of C_(2)H_(4) could reach 50.5%with a current density of 18 mA cm^(-2).The strong metal-support interaction could not only enhance the adsorption and activation of CO_(2),but also can stablize the CuO.

Thermal coupled photoconductivity as a tool to understand the photothermal catalytic reduction of CO2

Photocatalysis shows great promise in the field of solar energy conversion.One of the reasons for this is because it promotes the development of multi-field-coupled catalysis.In order to explore the principles of multi-field-coupled catalytic reactions,an in situ multi-field-coupled characterization technique is required.In this study,we obtained hydrogenated ST-01 TiO2 and observed enhanced catalytic activity by thermal coupled photocatalysis.In situ photoconductivity was employed to understand the activity enhancement.The effects of the reaction temperature,reaction atmosphere,and oxygen vacancy(Ov)on the photoconductivity of TiO2 were studied.After coupling thermal into photoconductivity measurement,highly active Ov-TiO2 displayed rapid decay of photoconductivity in a CO2 atmosphere and slow decay of photoconductivity in a N2 atmosphere.These phenomena revealed that photothermal coupling assisted the detrapping of electrons at the Ov surface and promoted electron transfer to CO2,which clearly explained the high photothermal catalytic activity of Ov-TiO2.This study demonstrated that photoconductivity is a useful tool to help understand photothermal catalytic phenomena.

Photoelectrocatalytic CO2 reduction based on metalloporphyrin-modified TiO2 photocathode

The conversion of CO2 and water to value-added chemicals under sunlight irradiation, especially by photoelectrocatalytic reduction process, is always a dream for human beings. A new artificial photosynthesis system composed of a metalloporphyrin-functionalized TiO2 photocathode and BiVO4 photoanode can efficiently transform CO2 and water to methanol, which is accompanied by oxygen release. This photoelectrocatalytic system smoothly produces methanol at a rate of 55.5 μM h^–1 cm^– 2, with 0.6 V being the membrane voltage in plants. The production of hydrogen can also be observed when the voltage is more than 0.75 V, due to photocatalysis. Our results evidently indicate that the molecules of metalloporphyrin attached onto the surface of anatase (TiO2) behave as chlorophyll, NADP, and Calvin cycle in plant cells.

Heterostructured Pd/PdO nanowires for selective and efficient CO_(2) electroreduction to CO

Palladium(Pd) nanostructures are highly promising electrocatalysts for the carbon dioxide electrochemical reduction(CO_(2) ER). At present, it is still challenge for the synthesis of Pd nanostructures with high activity, selectivity and stability. In this work, a facile PdII-complex pyrolysis method is applied to synthesize the high-quality one-dimensional heterostructured Pd/Pd O nanowires(Pd/Pd O H-NWs).The as-prepared Pd/Pd O H-NWs have a large electrochemically active surface area, abundant defects and Pd/Pd O heterostructure. Electrochemical measurement results reveal that Pd/Pd O H-NWs exhibit up to 94% CO Faraday efficiency with a current density of 11.6 m A cm^(-2) at an applied potential of -0.8 V. Meanwhile, Pd/Pd O H-NWs can achieve a stable catalytic process of 12 h for CO_(2) ER. Such outstanding CO_(2) ER performance of Pd/Pd O H-NWs has also been verified in the flow cell test. The density functional theory calculations indicate that Pd/Pd O heterostructure can significantly weaken the CO adsorption on Pd sites, which improves the CO tolerance and consequently enhances the catalytic performance of Pd/Pd O H-NWs for CO_(2) ER. This work highlights a facile complex pyrolysis strategy for the synthesis of Pd-based CO_(2) ER catalysts and provides a new application instance of metal/metal oxide heterostructure in electrocatalysis.

Electrocatalytic CO_(2) reduction towards industrial applications

Recently,research on the electrocatalytic CO_(2) reduction reaction(eCO_(2)RR)has attracted considerable attention due to its potential to resolve environmental problems caused by CO_(2) while utilizing clean energy and producing high‐value‐added products.Considerable theoretical research in the lab has demonstrated its feasibility and prospect.However,industrialization is mandatory to realize the economic and social value of eCO_(2)RR.For industrial application of eCO_(2)RR,more criteria have been proposed for eCO_(2)RR research,including high current density(above 200 mA cm^(−2)),high product selectivity(above 90%),and long‐term stability.To fulfill these criteria,the eCO_(2)RR system needs to be systematically designed and optimized.In this review,recent research on eCO_(2)RR for industrial applications is summarized.The review starts with focus on potential industrial catalysts in eCO_(2)RR.Next,potential industrial products are proposed in eCO_(2)RR.These products,including carbon monoxide,formic acid,ethylene,and ethanol,all have high market demand,and have shown high current density and product selectivity in theoretical research.Notably,the innovative components and strategy for industrializing the eCO_(2)RR system are also highlighted here,including flow cells,seawater electrolytes,solid electrolytes,and a two‐step method.Finally,some instructions and possible future avenues are presented for the prospects of future industrial application of eCO_(2)RR.

Tuning the intermediate reaction barriers by a CuPd catalyst to improve the selectivity of CO_(2) electroreduction to C_(2) products

Electrochemical CO2 reduction is a promising strategy for the utilization of CO2 and intermittent excess electricity.Cu is the only single metal catalyst that can electrochemically convert CO2 into multicarbon products.However,Cu exhibits an unfavorable activity and selectivity for the generation of C2 products because of the insufficient amount of CO*provided for the C‐C coupling.Based on the strong CO2 adsorption and ultrafast reaction kinetics of CO*formation on Pd,an intimate CuPd(100)interface was designed to lower the intermediate reaction barriers and improve the efficiency of C2 product formation.Density functional theory(DFT)calculations showed that the CuPd(100)interface enhanced the CO2 adsorption and decreased the CO2*hydrogenation energy barrier,which was beneficial for the C‐C coupling.The potential‐determining step(PDS)barrier of CO2 to C2 products on the CuPd(100)interface was 0.61 eV,which was lower than that on Cu(100)(0.72 eV).Encouraged by the DFT calculation results,the CuPd(100)interface catalyst was prepared by a facile chemical solution method and characterized by transmission electron microscopy.CO2 temperature‐programmed desorption and gas sensor experiments further confirmed the enhancement of the CO2 adsorption and CO2*hydrogenation ability of the CuPd(100)interface catalyst.Specifically,the obtained CuPd(100)interface catalyst exhibited a C2 Faradaic efficiency of 50.3%±1.2%at‒1.4 VRHE in 0.1 M KHCO3,which was 2.1 times higher than that of the Cu catalyst(23.6%±1.5%).This study provides the basis for the rational design of Cu‐based electrocatalysts for the generation of multicarbon products by fine‐tuning the intermediate reaction barriers.