Ultrafine ordered L1_(2)-Pt-Co-Mn ternary intermetallic nanoparticles as high-performance oxygen-reduction electrocatalysts for practical fuel cells

The long-range periodically ordered atomic structures in intermetallic nanoparticles(INPs)can significantly enhance both the electrocatalytic activity and electrochemical stability toward the oxygen reduction reaction(ORR)compared to the disordered atomic structures in ordinary solid-solution alloy NPs.Accordingly,through a facile and scalable synthetic method,a series of carbon-supported ultrafine Pt_3Co_(x)Mn_(1-x)ternary INPs are prepared in this work,which possess the"skin-like"ultrathin Pt shells,the ordered L1_(2) atomic structure,and the high-even dispersion on supports(L1_(2)-Pt_3Co_(x)Mn_(1-x)/~SPt INPs/C).Electrochemical results present that the composition-optimized L1_(2)-Pt_3Co_(0.7)Mn_(0.3)/~SPt INPs/C exhibits the highest electrocata lytic activity among the series,which are also much better than those of the pristine ultrafine Pt/C.Besides,it also has a greatly enhanced electrochemical stability.In addition,the effects of annealing temperature and time are further investigated.More importantly,such superior ORR electrocatalytic performance of L1_(2)-Pt_3Co_(0.7)Mn_(0.3)/~SPt INPs/C are also well demonstrated in practical fuel cells.Physicochemical characterization analyses further reveal the major origins of the greatly enhanced ORR electrocata lytic performance:the Pt-Co-Mn alloy-induced geometric and ligand effects as well as the extremely high L1_(2) atomic-ordering degree.This work not only successfully develops a highly active and stable ordered ternary intermetallic ORR electrocatalyst,but also elucidates the corresponding"structure-function"relationship,which can be further applied in designing other intermetallic(electro)catalysts.

An optimized smearing scheming for first Brillouin zone sampling and its application on thermal conductivity prediction of graphite

We propose an optimized scheme to determine the smearing parameter in the Gaussian function that is used to replace the Dirac δ function in the first Brillouin zone sampling. The broadening width is derived by analyzing the difference of the results from the phase-space method and Gaussian broadening method. As a demonstration, using the present approach,we investigate the phonon transport in a typical layered material, graphite. Our scheme is benchmarked by comparing with other zone sampling methods. Both the three-phonon phonon scattering rates and thermal conductivity are consistent with the prediction from the widely used tetrahedron method and adaptive broadening method. The computational efficiency of our scheme is more than one order of magnitude higher than the two other methods. Furthermore, the effect of fourphonon scattering in phonon transport in graphite is also investigated. It is found that four-phonon scattering reduces the through-plane thermal conductivity by 10%. Our methods could be a reference for the prediction of thermal conductivity of anisotropic material in the future.

Simulation design and optimization of reactors for carbon dioxide mineralization

To achieve a synergistic solution for both sustainable waste management and permanent CO_(2) sequestration,CO_(2) mineralization via fly ash particles is an option.Based on computational fluid dynamics,two specialized reactors for fly ash mineralization were designed.The reactor designs were strategically tailored to optimize the interactions between fly ash particles and flue gas within the reactor chamber while concurrently facilitating efficient post-reaction-phase separation.The impinging-type inlet configuration dramatically enhanced the interfacial interaction between the fly ash particles and the gaseous mixture,predominantly composed of CO_(2) and steam.This design modality lengthens the particle residency and reaction times,substantially augmenting the mineralization efficiency.A rigorous investigation of three operational parameters,that is,flue gas velocity,carrier gas velocity,and particle velocity,revealed their influential roles in gas-particle contact kinetics.Through a computational investigation,it can be ascertained that the optimal velocity regime for the flue gas was between 20 and 25 m⋅s1.Concurrently,the carrier gas velocity should be confined to the range of 9-15 m⋅s1.Operating within these finely tuned parameters engenders a marked enhancement in reactor performance,thereby providing a robust theoretical basis for operational efficacy.Overall,a judicious reactor design was integrated with data-driven parameter optimization.

Visible-light driven room-temperature coupling of methane to ethane by atomically dispersed Au on WO_(3)

Gold(Au)as co-catalyst is remarkable for activating methane(CH4),especially atomically dispersed Au with maximized exposing active sites and specific electronic structure.Furthermore,singlet oxygen(^(1)O_(2))typically manifests a mild redox capacity with a high selectivity to attack organic substrates.Peroxomonosulfate(PMS)favors to produce oxidative species 102 during the photocatalytic reactions.Thus,combining atomic Au as co-catalyst and ^(1)O_(2) as oxidant is an effective strategy to selectively convert CH4.Herein,we synthesized atomically dispersed Au on WO_(3)(Au/WO_(3)),where Au was in the forms of single atoms and clusters.At room temperature,such Au/WO_(3) exhibited enhanced photocata lytic conversion of CH4 to CH3 CH3 with a selectivity,up to 94%,under visible light.The radicals-pathway mechanism of CH4 coupling has also been investigated through detection and trapping experiment of active species.Theoretical calculations further interpret the electronic structure of Au/WO_(3) and tip-enhanced local electric field at the Au sites for promoting CH4 conversion.

Stabilizing the MAPbI3 perovksite via the in-situ formed lead sulfide layer for efficient and robust solar cells

Surface passivation via post-treatment with organic reagents is a popular strategy to improve the stability and efficiency of perovskite solar cell. However, organic passivation still suffers from the weak bonding between organic chemicals and perovskite layers. Here we reported a facile inorganic layer passivating method containing strong Pb–S bonding by using ammonium sulfide treatment. A compact PbS_x layer was in-situ formed on the top surface of the perovskite film, which could passivate and protect the perovskite surface to enhance the performance and stability. Our novel inorganic passivation layer strategy demonstrates great potential for the development of high efficiency hybrid and robust perovskite optoelectronics.

Machine learning-based ionic liquids design and process simulation for CO_(2) separation from flue gas

Rational design of ionic liquids(ILs),which is highly dependent on the accuracy of the model used,has always been crucial for CO_(2)separation from flue gas.In this study,a support vector machine(SVM)model which is a machine learning approach is established,so as to improve the prediction accuracy and range of IL melting points.Based on IL melting points data with 600 training data and 168 testing data,the estimated average absolute relative deviations(AARD)and squared correlation coefficients(R^(2))are 3.11%,0.8820 and 5.12%,0.8542 for the training set and testing set of the SVM model,respectively.Then,through the melting points model and other rational design processes including conductor-like screening model for real solvents(COSMO-RS)calculation and physical property constraints,cyano-based ILs are obtained,in which tetracyanoborate[TCB]-is often ruled out due to incorrect estimation of melting points model in the literature.Subsequently,by means of process simulation using Aspen Plus,optimal IL are compared with excellent IL reported in the literature.Finally,1-ethyl-3-methylimidazolium tricyanomethanide[EMIM][TCM]is selected as a most suitable solvent for CO_(2)separation from flue gas,the process of which leads to 12.9%savings on total annualized cost compared to that of 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide[EMIM][Tf_(2)N].

Synergistic stabilization of CsPbI_(3) inorganic perovskite via 1D capping and secondary growth

Cesium lead iodide(CsPbI_(3)) perovskite has gained great attention in the photovoltaic(PV) community because of its unique optoelectronic properties, good chemical stability and appropriate bandgap for sunlight harvesting applications. However, compared to solar cells fabricated from organic-inorganic hybrid perovskites, the commercialization of devices based on all-inorganic CsPbI_(3) perovskites still faces many challenges regarding PV performance and long-term stability. In this work, we discovered that tetrabutylammonium bromide(TBABr) post-treatment to CsPbI_(3) perovskite films could achieve synergistic stabilization with both TBA+cation intercalation and Br-doping. Such TBA^(+) cation intercalation leads to onedimensional capping with TBAPb I3 perovskite formed in situ, while the Br-induced crystal secondary growth helps effectively passivate the defects of CsPbI_(3) perovskite, thus enhancing the stability. In addition, the incorporation of TBABr can improve energy-level alignment and reduce interfacial charge recombination loss for better device performance. Finally, the highly stable TBABr-treated CsPbI_(3)-based perovskite solar cells show reproducible photovoltaic performance with a champion efficiency up to 19.04%, while retaining 90% of the initial efficiency after 500 h storage without encapsulation.

An experimental study on RP-3 jet fuel injection on a common rail injection system

RP-3 jet fuel could be an alternative fuel for diesel engines.In this study,the injection characteristics of RP-3jet fuel under single and split injection strategies were investigated and compared with diesel fuel.The experimental results indicate that RP-3 jet fuel has slightly shorter injection delay time than diesel fuel,but this difference is negligible in actual engine operations.Further,although the lower density and viscosity of RP-3 jet fuel lead to higher volumetric injection rates and cycle-based injection quantities,the cycle-based injection mass and the mass injection rates at the stable injection stage of RP-3 jet fuel are close to or slightly lower than those of diesel fuel.Based on these experimental observations,it could be concluded that fuel physical properties are the secondary factor influencing the injection characteristics in both single and split injection strategies,as RP-3 jet fuel and diesel fuel are taken for comparison.

Molecular simulation on carbon dioxide capture performance for carbons doped with various elements

Among the different types of CO_(2)capture technologies for post-combustion,sorption CO_(2)capture technology with carbon-based sorbents have been extensively explored with the purpose of enhancing their sorption perfor-mance by doping hetero elements due to the rapid reaction kinetics and low costs.Herein,sorption capacity and selectivity for CO_(2)and N 2 on carbon-based sorbents doped with elements such as nitrogen,sulfur,phosphorus,and boron,are evaluated and compared using the grand canonical Monte Carlo(GCMC)method,the universal force field(UFF),and transferable potentials for phase equilibria(TraPPE).The sorption capacities of N-doped porous carbons(PCs)at 50℃were 76.1%,70.7%,50.6%,and 35.7%higher than those of pure PCs,S-doped PCs,P-doped PCs,and B-doped PCs,respectively.Its sorption selectivity at 50℃was approximately 14.0,nearly twice that of pure PCs or other hetero-element-doped PCs.The N-doped PCs showed the largest sorption heat at 50℃among all the PCs,approximately 20.6 kJ·mol^(−1),which was 9.7%−25.5%higher than that of the pure PCs under post-combustion conditions.Additionally,with the product purity of 41.7 vol.%−75.9 vol.%for vacuum pressure swing sorption,and 53.4 vol.%−83.6 vol.%for temperature swing sorption,the latter is more suitable for post-combustion conditions than pressure-swing sorption.

Frontier science and challenges on offshore carbon storage

Carbon capture and storage(CCS)technology is an imperative,strategic,and constitutive method to considerably reduce anthropogenic CO_(2)emissions and alleviate climate change issues.The ocean is the largest active carbon bank and an essential energy source on the Earth's surface.Compared to oceanic nature-based carbon dioxide removal(CDR),carbon capture from point sources with ocean storage is more appropriate for solving short-term climate change problems.This review focuses on the recent state-of-the-art developments in offshore carbon storage.It first discusses the current status and development prospects of CCS,associated with the chailenges and uncertainties of oceanic nature-based CDR.The second section outlines the mechanisms,sites,advantages,and ecologic hazards of direct offshore CO_(2)injection.The third section emphasizes the mechanisms,schemes,influencing factors,and recovery efficiency of ocean-based CO-CH_(4)replacement and CO_(2)-enhanced oil recovery are reviewed.In addition,this review discusses the economic aspects of offshore CCS and the preponderance of offshore CCs hubs.Finally,the upsides,limitations,and prospects for further investigation of offshore CO_(2)storage are presented.

Chiral helically grooved gold nanoarrows for concurrently enhancing oxygen and hydrogen evolution from electrochemical water splitting

Electrocatalytic water splitting shows a tremendous promise for storing green and intermittent electricity into storable fuels,paving a sustainable way toward carbon neutrality. The exploration of a bifunctional electrocatalyst for simultaneously enhancing oxygen evolution reaction and hydrogen evolution reaction is at the core yet remains a grand challenge, especially operated in the same electrolyte. In this work, mesoscale gold nanoarrows with special chiral morphology are synthesized for electrocatalytic water splitting. In the same electrolyte of 1 M KOH aqueous solution, the as-designed chiral R-/L-helically grooved gold nanoarrows(R-/L-heli GNAs) demonstrated significantly enhanced performance in both hydrogen evolution reaction and oxygen evolution reaction with overpotentials of 186 and 355 m V at 10 m A cm^(-2), respectively, compared to the achiral counterpart. For oxygen evolution reaction, the performance is even comparable to commercial notable metal catalysts,i.e., RuO_(2), of which the overpotential is 310 m V under the same measured conditions. The spin-polarized conductive atomic force microscope(c-AFM), finite-difference time-domain simulation, in combination with electrochemical investigations, show that the chirality of R-/L-heli GNAs makes a substantial contribution toward the remarkable performance by enhanced electric field distribution for hydrogen evolution reaction and by tuning the spin states of the electrons for oxygen evolution reaction.This study presents an encouraging strategy for simultaneously promoting hydrogen evolution reaction and oxygen evolution reaction that operated in the same electrolyte by imparting chirality toward a mesoscale inorganic electrocatalyst, showing a grand promise for opening up a new way for electrocatalytic water splitting toward green hydrogen.

High-performance Bi_(2)S_(3)/ZnO photoanode enabled by interfacial engineering with oxyanion for efficient photoelectrochemical water oxidation

In the present contribution,we demonstrate that the sluggish kinetics of oxygen evolution reaction(OER)over the bismuth sulfide(Bi_(2)S_(3))photoanode,which severely restricts its photoelectrochemical activity,is markedly accelerated by employing a sulfatecontaining electrolyte.First-principle calculation points to the spontaneous adsorption of sulfate(SO_(4)^(2−))on Bi_(2)S_(3)and its capacity of stabilizing the OER intermediates through hydrogen bonding,which is further reinforced by increasing the local density of states near the Fermi level of Bi_(2)S_(3).Meanwhile,the electron transfer is also promoted to synergistically render the ratedetermining step(from O*to OOH*)of OER over Bi_(2)S_(3)kinetically facile.Last but not least,benefitting from such enhanced OER activity and efficient charge separation resulted from depositing Bi_(2)S_(3)on the zinc oxide nanorods(ZnO NRs),forming a core–shell heterojunction,its photocurrent density achieves 8.61 mA·cm^(−2)at 1.23 VRHE,far surpassing those reported for additional Bi_(2)S_(3)-based and several state-of-the-art photoanodes in the literature and further exceeding their theoretical limit.The great promise of the Bi_(2)S_(3)/ZnO NRs is in view of such outperformance,the superior Faradaic yield of oxygen of more than~80%and the outstanding half-cell applied bias photon-to-current efficiency of~1%well corroborated.

Platinum-cobalt synergy redefines electrocatalytic lignin upgrading

The heavy consumption of non-renewable fossil feedstocks has induced several vital problems such as global warming and energy crises.Biomass,particularly lignin,is a promising renewable resource to substitute fossil fuels for producing value-added chemicals and fuels[1–3].Lignin has a highly irregular and recalcitrant structure that constituted by coumaryl,coniferyl and sinapyl alcohol monomers via intermolecular C–O and C–C bonds in a random order.For a long time,lignin has been regarded as a waste source and burnt for heat.Recently,the high values of lignin as a feedstock to bridge future gaps to supply aromatics have been extensively recognized and various catalytic strategies to transform lignin into arenes,cycloalkanes,etc.have been reported.

光驱动Rh/InGaN_(1-x)O_(x)纳米组装体甲烷干重整制合成气

Light-driven dry reforming of methane toward syngas presents a proper solution for alleviating climate change and for the sustainable supply of transportation fuels and chemicals.Herein,Rh/InGaN_(1-x)O_(x) nanowires supported by silicon wafer are explored as an ideal platform for loading Rh nanoparticles,thus assembling a new nanoarchitecture for this grand topic.In combination with the remarkable photothermal synergy,the O atoms in Rh/InGaN_(1-x)O_(x) can significantly lower the apparent activation energy of dry reforming of methane from 2.96 eV downward to 1.70 eV.The as-designed Rh/InGaN_(1-x)O_(x) NWs nanoarchitecture thus demonstrates a measurable syngas evolution rate of 180.9 mmol g_(cat)^(-1) h^(-1) with a marked selectivity of 96.3% under concentrated light illumination of 6 W cm^(-2).What is more,a high turnover number(TON)of 4182 mol syngas per mole Rh has been realized after six reuse cycles without obvious activity degradation.The correlative 18O isotope labeling experiments,in-situ irradiated X-ray photoelectron spectroscopy(ISI-XPS)and in-situ diffuse reflectance Fourier transform infrared spectroscopy characterizations,as well as density functional theory calculations reveal that under light illumination,Rh/InGaN_(1-x)O_(x) NWs facilitate releasing^(*)CH_(3) and H^(+)from CH_(4) by holes,followed by H_(2) evolution from H^(+)reduction with electrons.Subsequently,the O atoms in Rh/InGaN_(1-x)O_(x) can directly participate in CO generation by reacting with the ^(*)C species from CH_(4) dehydrogenation and contributes to the coke elimination,in concurrent formation of O vacancies.The resultant O vacancies are then replenished by CO_(2),showing an ideal chemical loop.This work presents a green strategy for syngas production via light-driven dry reforming of methane.

Photocatalytic reduction of carbon dioxide by titanium oxide- based semiconductors to produce fuels

To tackle the crisis of global warming, it is imperative to control and mitigate the atmospheric carbon dioxide level. Photocatalytic reduction of carbon dioxide into solar fuels furnishes a gratifying solution to utilize and reduce carbon dioxide emission and simultaneously generate renewable energy to sustain the societies. So far, titanium oxide-based semiconductors have been the most prevalently adopted catalysts in carbon dioxide photoreduction. This mini-review provides a general summary of the recent progresses in titanium oxide- catalyzed photocatalytic reduction of carbon dioxide. It first illustrates the use of structural engineering as a strategy to adjust and improve the catalytic performances. Then, it describes the introduction of one/two exogenous elements to modify the photocatalytic activity and/or selectivity. Lastly, it discusses multi-component hybrid titanium oxide composites.

Toward carbon neutrality:Uncovering constraints on critical minerals in the Chinese power system

China has set up its ambitious carbon neutrality target,which mainly relies on significant energy-related carbon emissions reduction.As the largest important contributing sector,power sector must achieve energy transition,in which critical minerals will play an essential role.However,the potential supply and demand for these minerals are uncertain.This study aims to predict the cumulative demand for critical minerals in the power sector under different scenarios via dynamic material flow analysis(DMFA),including total demands,supplies and production capacities of different minerals.Then,these critical minerals are categorized into superior and scarce resources for further analysis so that more detailed results can be obtained.Results present that the total minerals supply will not meet the total minerals demand(74260 kt)in 2060.Serious resource shortages will occur for several key minerals,such as Cr,Cu,Mn,Ag,Te,Ga,and Co.In addition,the demand for renewable energy will be nearly fifty times higher than that of fossil fuels energy,implying more diversified demands for various minerals.Finally,several policy recommendations are proposed to help improve the overall resource efficiency,such as strategic reserves,material substitutions,and circular economy.

Stable Combustion under Carbon Dioxide Enriched Methane Blends For Exhaust Gas Recirculation(EGR)

Exhaust gas recirculation(EGR)is one of the main techniques to enable the use of oxyfuel combustion for carbon capture and storage(CCS).However,the use of recirculated streams with elevated carbon dioxide poses different challenges.Thus,more research is required about the cumulative effects on the desirable outcomes of the combustion processes such as thermal efficiency,reduced emissions and system operability,when fuels with high CO_(2) concentration for CCS exhaust gas recirculation or biogas are used.Therefore,this study evaluates the use of various CO_(2) enriched methane blends and their response towards the formation of a great variety of structures that appear in swirling flows,which are the main mechanism for combustion control in current gas turbines systems.The study uses 100 kW acoustically excited swirl-stabilised burner to investigate the flow field response to the resultant effects of the variation in the swirl strength,excitation under isothermal condition and the corresponding effects during combustion with different fuels at various CO_(2) concentrations.Results show changes in size and location of flow structures as a result of the changes in the mean and turbulent velocities of the flow field,consequence of the imposition of different swirl and forcing conditions.Improved thermal efficiency is also observed in the system when using high swirl and forcing while the blend of CO_(2) with methane balanced the heat release fluctuation with a corresponding reduction in the acoustic amplitudes of the combustion response,suggesting that certain CO_(2) concentrations in the fuel can provide more stable flames.Concentrations between 10%to 15%CO_(2) volume show great promise for stability improvement,with the potential of using these findings in larger units that employ CCS technologies.

China’s energy transitions for carbon neutrality:challenges and opportunities

The pledge of achieving carbon peak before 2030 and carbon neutrality before 2060 is a strategic decision that responds to the inherent needs of China’s sustainable and high-quality development,and is an important driving force for promoting China’s ecological civilization constructions.As the consumption of fossil fuel energy is responsible for more than 90%of China’s greenhouse gases emissions,policies focusing on energy transition are vital for China accomplishing the goal of carbon neutrality.Considering the fact that China’s energy structure is dominated by fossil fuels,especially coal,it is urgent to accelerate the low-carbon transition of the energy system in a relatively short time,and dramatically increase the proportion of clean energy in the future energy supply.Although China has made notable progress in the clean energy transition in the past,its path to carbon neutrality still faces many significant challenges.During the process of energy transformation,advanced technologies and greater investment will play essential parts in this extensive and profound systemic reform for China’s economy and society.In the meantime,these changes will create immense economic opportunities and geopolitical advantages.

An accurate battery state of health estimation method easy to imlement after charging

While lithium-ion batteries are widely deployed to large-scale applications,such as electric vehicles and stationary energy storage plants,the gradual degradation of batteries impose significant influence on their safety and efficiency during operation.

Target the neglected VOCs emission from iron and steel industry in China for air quality improvement

Recent years have witnessed significant improvement in China’s air quality.Strict environmental protection measures have led to significant decreases in sulfur dioxide(SO2),nitrogen oxides(NOx),and particulate matter(PM)emissions since 2013.But there is no denying that the air quality in 135 cities is inferior to reaching the Ambient Air Quality Standards(GB 3095–2012)in 2020.In terms of temporal,geographic,and historical aspects,we have analyzed the potential connections between China’s air quality and the iron and steel industry.The non-target volatile organic compounds(VOCs)emissions from iron and steel industry,especially from the iron ore sinter process,may be an underappreciated index imposing a negative effect on the surrounding areas of China.Therefore,we appeal the authorities to pay more attention on VOCs emission from the iron and steel industry and establish new environmental standards.And different iron steel flue gas pollutants will be eliminated concurrently with the promotion and application of new technology.