Trade-offs and synergies between ecosystem services in Yutian County along the Keriya River Basin,Northwest China

The Keriya River Basin is located in an extremely arid climate zone on the southern edge of the Tarim Basin of Northwest China,exhibiting typical mountain-oasis-desert distribution characteristics.In recent decades,climate change and human activities have exerted significant impacts on the service functions of watershed ecosystems.However,the trade-offs and synergies between ecosystem services(ESs)have not been thoroughly examined.This study aims to reveal the spatiotemporal changes in ESs within the Keriya River Basin from 1995 to 2020 as well as the trade-offs and synergies between ESs.Leveraging the Integrated Valuation of Ecosystem Services and Trade-offs(InVEST)and Revised Wind Erosion Equation(RWEQ)using land use/land cover(LULC),climate,vegetation,soil,and hydrological data,we quantified the spatiotemporal changes in the five principal ESs(carbon storage,water yield,food production,wind and sand prevention,and habitat quality)of the watershed from 1995 to 2020.Spearman correlation coefficients were used to analyze the trade-offs and synergies between ES pairs.The findings reveal that water yield,carbon storage,and habitat quality exhibited relatively high levels in the upstream,while food production and wind and sand prevention dominated the midstream and downstream,respectively.Furthermore,carbon storage,food production,wind and sand prevention,and habitat quality demonstrated an increase at the watershed scale while water yield exhibited a decline from 1995 to 2020.Specifically,carbon storage,wind and sand prevention,and habitat quality presented an upward trend in the upstream but downward trend in the midstream and downstream.Food production in the midstream showed a continuously increasing trend during the study period.Trade-off relationships were identified between water yield and wind and sand prevention,water yield and carbon storage,food production and water yield,and habitat quality and wind and sand prevention.Prominent temporal and spatial synergistic relationships were observed between different ESs,notably between carbon storage and habitat quality,carbon storage and food production,food production and wind and sand prevention,and food production and habitat quality.Water resources emerged as a decisive factor for the sustainable development of the basin,thus highlighting the intricate trade-offs and synergies between water yield and the other four services,particularly the relationship with food production,which warrants further attention.This research is of great significance for the protection and sustainable development of river basins in arid areas.

Spatiotemporal variations in ecosystem services and their trade-offs and synergies against the background of the gully control and land consolidation project on the Loess Plateau,China

Studying the spatiotemporal variations in ecosystem services and their interrelationships on the Loess Plateau against the background of the gully control and land consolidation(GCLC)project has significant implications for ecological protection and quality development of the Yellow River Basin.Therefore,in this study,we took Yan'an City,Shaanxi Province of China,as the study area,selected four typical ecosystem services,including soil conservation service,water yield service,carbon storage service,and habitat quality service,and quantitatively evaluated the spatiotemporal variation characteristics and trade-offs and synergies of ecosystem services from 2010 to 2018 using the Integrated Valuation of Ecosystem Services and Trade-offs(InVEST)model.We also analysed the relationship between the GCLC project and regional ecosystem service changes in various regions(including 1 city,2 districts,and 10 counties)of Yan'an City and proposed a coordinated development strategy between the GCLC project and the ecological environment.The results showed that,from 2010 to 2018,soil conservation service decreased by 7.76%,while the other three ecosystem services changed relatively little,with water yield service increasing by 0.56% and carbon storage service and habitat quality service decreasing by 0.16% and 0.14%,respectively.The ecological environment of Yan'an City developed in a balanced way between 2010 and 2018,and the four ecosystem services showed synergistic relationships,among which the synergistic relationships between soil conservation service and water yield service and between carbon storage service and habitat quality service were significant.The GCLC project had a negative impact on the ecosystem services of Yan'an City,and the impact on carbon storage service was more significant.This study provides a theoretical basis for the scientific evaluation of the ecological benefits of the GCLC project and the realization of a win-win situation between food security and ecological security.

Tradeoffs and synergies between ecosystem services : A comparison of the karst and non-karst area

Under the influence of various natural and human factors, the relationship between the ecosystem services provided for human beings by a karst ecosystem is becoming increasingly complex, profoundly limiting the effective and sustainable development of the social economy and ecosystem protection in karst areas. Taking Guizhou, China as an example, which includes both karst(including five different landforms) and non-karst area, the study explored and compared the tradeoff and synergy between ecosystem services in both terrain types. The results showed higher change rates of water yield and soil retention in karst areas than those in non-karst areas, with only small differences in the carbon storage and crop production change. The ecosystem service relationships in the karst area from 1995 to 2005 were consistent with the relationships in the non-karst area. However, differences were observed in most of these relationships from 2005 to 2015. The relationships between ecosystem services in different karst landforms from 1995 to 2005 remained the same, but there are differences found in the relationships of ecosystem services from 2005 to 2015. The trade-off and synergistic relationships between ecosystem services in the different landforms were closely related to the changes of climate and land use, particularly related to rainfall, rainfall erosivity, farmland, and forestland.

Synergies and trade-offs of climate-smart agriculture(CSA)practices selected by smallholder farmers in Geshy watershed,Southwest Ethiopia

Studies on mainstreaming climate-smart agriculture(CSA)practices can increase smallholder farmers’capacity and awareness to improve food security and establish sustainable livelihoods through resilient agricultural systems,while achieving adaptation and mitigation benefits.Hence,valuable insights can be obtained from smallholder farmers in responding to present and forthcoming challenges of climate change impacts.However,there is little research work on trade-off and synergy assessments.Taking Geshy watershed in Southwest Ethiopia as a case study area,both quantitative and qualitative data analysis were undertaken in this study.The data were collected from 15 key informant interviews,6 focus group discussions,and 384 households to answer the following questions:(1)what are the top 5 preferred CSA practices for smallholder farmers in Geshy watershed when coping with the impacts of climate change?(2)What is the performance of the preferred CSA practices?And(3)which trade-offs and synergies are experienced upon the implementation of CSA practices?The study came up with the most preferred CSA practices such as the use of improved crop varieties,small-scale irrigation,improved animal husbandry,the use of efficient inorganic fertilizers,and crop rotation with legumes.The selected CSA practices showed that the productivity goal exhibit the best synergy,while the mitigation goal has trade-offs.The study also indicated that the use of improved crop varieties causes high synergies in all 3 goals of CSA practices;small-scale irrigation provides a medium synergy on productivity goal but high synergy for adaptation and mitigation goals;improved animal husbandry shows a high synergy with the adaptation goal,a relatively lower synergy with the productivity goal,and a trade-off with the mitigation goal;the use of efficient inorganic fertilizers shows maximum synergy for the productivity and adaptation goals;and crop rotation with legumes exhibits high synergy with the productivity and mitigation goals but a relatively lower synergy with the adaptation goal.These results can provide evidence to various stakeholder farmers in the value chain that the impacts of climate change can be addressed by the adoption of CSA practices.In general,CSA practices are considered indispensable.Smallholder farmers prefer CSA practices that help to increase crop productivity and household resilience to climate change impacts.The results generate a vital foundation for recommendations to smallholder farming decision-makers.It also sensitizes actions for innovative and sustainable methods that are able to upscale the preferred CSA practices in the agricultural system in Geshy watershed of Southwest Ethiopia and other regions.

Security-Reliability Tradeoff Analysis for Jamming Aided Decode-and-Forward Relay Networks

In this paper,we explore a cooperative decode-and-forward(DF)relay network comprised of a source,a relay,and a destination in the presence of an eavesdropper.To improve physical-layer security of the relay system,we propose a jamming aided decodeand-forward relay(JDFR)scheme combining the use of artificial noise and DF relaying which requires two stages to transmit a packet.Specifically,in stage one,the source sends confidential message to the relay while the destination acts as a friendly jammer and transmits artificial noise to confound the eavesdropper.In stage two,the relay forwards its re-encoded message to the destination while the source emits artificial noise to confuse the eavesdropper.In addition,we analyze the security-reliability tradeoff(SRT)performance of the proposed JDFR scheme,where security and reliability are evaluated by deriving intercept probability(IP)and outage probability(OP),respectively.For the purpose of comparison,SRT of the traditional decode-and-forward relay(TDFR)scheme is also analyzed.Numerical results show that the SRT performance of the proposed JDFR scheme is better than that of the TDFR scheme.Also,it is shown that for the JDFR scheme,a better SRT performance can be obtained by the optimal power allocation(OPA)between the friendly jammer and user.

Tailoring the microenvironment of Ti sites in Ti-containing materials for synergizing with Au sites to boost propylene epoxidation

Au sites supported on Ti-containing materials(Au/Ti-containing catalyst)are currently considered as a promising catalyst for the propylene epoxidation owing to the synergistic effect that hydrogen peroxide species formed on Au sites diffuses to the Ti sites to form the Ti-hydroperoxo intermedi-ates and contributes to the formation of propylene oxide(PO).In principle,thermal treatment will significantly affect the chemical and physical structures of Ti-containing materials.Consequently,the synergy between tailored Ti sites with different surface properties and Au sites is highly ex-pected to enhance the catalytic performance for the reaction.Herein,we systematically studied the intrinsic effects of different microenvironments around Ti sites on the PO adsorption/desorption and conversion,and then effectively improved the catalytic performance by tailoring the number of surface hydroxyl groups.The Ti^(Ⅵ)material with fewer hydroxyls stimulates a remarkable enhance-ment in PO selectivity and H_(2)efficiency compared to the Ti^(Ⅵ)material that possessed more hydrox-yls,offering a 7-fold and 4-fold increase,respectively.As expected,the Ti^(Ⅵ)+Ⅳand Ti^(Ⅳ)materials also exhibit a similar phenomenon to the Ti^(Ⅵ)materials through the same thermal treatment,which strongly supports that the Ti sites microenvironment is an important factor in suppressing PO con-version and enhancing catalytic performance.These insights could provide guidance for the rational preparation and optimization of Ti-containing materials synergizing with Au catalysts for propylene epoxidation.

Trade-Offs and Synergie Effects of Regulating Ecosystem Services along an Climatic Gradient in Slovakia

This study aims to assess the synergies and trade-offs of regulating ecosystem services. Ecosystem services are non-linearly interconnected and changes in one service can positively or negatively affect another. We evaluated ecosystem services based on biophysical indicators using an expert scoring system that determines the corresponding soil functions and is part of the existing databases available in Slovakia. This methodological combination enabled us to provide unique mapping and assessment of ecosystem services within Slovakia. Correlation analysis between individual regulating ecosystem services and climate regions, slope, texture, and altitude confirm the statistically significant influence of climate and slope in all agricultural land, arable land, and grassland ecosystems. Statistically significant synergistic effects were established between the regulation of the water regime and the regulation of soil erosion within each climate region, apart from the very warm climate region. Only in a very warm climate region was potential of regulating ecosystem services mutually beneficial for soil erosion control and soil cleaning potential (immobilization of inorganic pollutants).

Trade-offs and Synergies of Ecosystem Services in Karst Area of China Driven by Grain-for-Green Program

As an important means regulating the relationship between human and natural ecosystem,ecological restoration program plays a key role in restoring ecosystem functions.The Grain-for-Green Program(GFGP,One of the world’s most ambitious ecosystem conservation set-aside programs aims to transfer farmland on steep slopes to forestland or grassland to increase vegetation coverage)has been widely implemented from 1999 to 2015 and exerted significant influence on land use and ecosystem services(ESs).In this study,three ecological models(In VEST,RUSLE,and CASA)were used to accurately calculate the three key types of ESs,water yield(WY),soil conservation(SC),and net primary production(NPP)in Karst area of southwestern China from 1982 to 2015.The impact of GFGP on ESs and trade-offs was analyzed.It provides practical guidance in carrying out ecological regulation in Karst area of China under global climate change.Results showed that ESs and trade-offs had changed dramatically driven by GFGP.In detail,temporally,SC and NPP exhibited an increasing trend,while WY exhibited a decreasing trend.Spatially,SC basically decreased from west to east;NPP basically increased from north to south;WY basically increased from west to east;NPP and SC,SC and WY developed in the direction of trade-offs driven by the GFGP,while NPP and WY developed in the direction of synergy.Therefore,future ecosystem management and restoration policy-making should consider trade-offs of ESs so as to achieve sustainable provision of ESs.

Potential tradeoffs between intraspecific and interspecific trait variations along an environmental gradient in a subtropical forest

There has been growing attention to intraspecific variation in trait-based plant ecology. However, studies on these changes across ontogenetic stages and the potential trade-offs with interspecific traits along environmental gradients are rare. In this study, we measured six wood and bark traits of 1030 trees of six species(Castanopsis nigrescens; C. carlesii; Lithocarpus polystachyus; L. synbalanos; Ormosia glaberrima; O. pachycarpa) from a10-ha plot in a subtropical forest. Mean intraspecific variation in bark thickness and bark percentage to DBH was more than twice that for wood density and bark density.Bark thickness and bark percentage showed a consistent trend with increasing tree size. Small-tree traits were more variable than the same traits in larger trees. Altitude,convexity and soil nutrients explained the majority of the variations in the six traits, while sibling species had similar relationships between traits and environmental variables.Trees with dense wood and thin bark were usually found on steep slopes at lower altitudes. Our findings show intraspecific trait variability has different spatial patterns compared with interspecific variabilities along an environmental gradient.

Grain production space reconstruction and land system function tradeoffs in China

Grain production space reconstruction referred to the changes in the quantity,quality and pattern of grain produc-tion space caused by functional tradeoffs and conflicts between grain production space,urban-rural development space,and ecological service space.Exploring tradeoffs between land system functions caused by grain produc-tion space reconstruction was particularly important for ensuring food security,promoting the construction of ecological civilization,and achieving sustainable development.Therefore,this study identified four relationships of land system functions during the process of grain production space reconstruction(1980-2018)in China by using Set Pair Analysis.Research results showed that the reconstruction of grain production space was achieved mainly through three pathways:Grain for Green,deforestation and reclamation,and urban expansion.Generally,ecological service had spatial negative correlation with grain production,economic development and population carrying capacity(P<0.01),but grain production,economic development and population carrying capacity were positively correlated with each other(P<0.01).In the process of grain production space reconstruction,eco-logical services and economic development,ecological services and population carrying capacity had all shown inverse synergies;there was a tradeoffbetween grain production and ecological services,a codirectional tradeoffbetween grain production and economic development,but a strong synergy between economic development and population carrying capacity.However,the functions of land systems only appeared as synergies or tradeoffs,and there were no inverse synergies and codirectional tradeoffs in the separate processes of Grain for Green,deforestation and reclamation,and urban expansion.It can be concluded that the relationships between land system functions were relatively simple in a single process,but it became complex and diverse when multiple processes were integrated for system analysis.

Trade-offs/Synergies in Land-use Function Changes in Central China from 2000 to 2015

To solve the problems caused by irrational land-use, studying the functions of land-use, its changing characteristics, and the relationship between each land-use function will be beneficial for achieving sustainable land development. In this research, we constructed an evaluation framework of multiple land-use functions(LUFs) based on sustainable land-use theory. Specifically,, we classified the multiple LUFs into three types: agricultural production function(APF), living function(LVF), and ecological service function(ESF).We then spatialized the economic and social data, and implemented the InVEST(Integrated Valuation of Ecosystem Services and Tradeoffs) model and RUSLE(Revised Universal Soil Loss Equation) model to evaluate each sub-LUF(crop production, aquatic production, woodlands production, livestock production, living space, life quality, water supply, soil conservation, climate regulation, biological conservation) in central China in 2000 and again in 2015. Moreover, by analyzing the changes to LUFs and the relationships between each LUF change, we were able to discern patterns of LUF change in central China. The results show that: (1)42.12% of total territory in the study area increased their APF from 2000 to 2015, while 43.41% of the lands increased their ESF yet only 8.98% of the lands increased their LVF;(2) in Hubei and Hunan, there was more land with an increase of APF than in Anhui or Jiangxi. The APF in Jiangxi exhibited the greatest decline over time period, the LVF increased more in the provincial capital cities than in other regions, and the ESF expanded more in Jiangxi than in the other provinces;and (3) the changes in APF were significantly and positively correlated with changes in LVF. Additionally, changes in ESF were negatively but non-significantly correlated with changes in APF and LVF.

Trade-offs and Synergies of Ecosystem Services in the Taihu Lake Ba- sin of China

Understanding the spatial interactions among multiple ecosystem services is crucial for ecosystem services management. Ecosystem services, including crop production, freshwater supply, aquatic production, net primary production, soil conservation, water conservation, flood regulation, forest recreation, were measured at 1-km grid scale covering the Taihu Lake Basin(TLB) of China. Our objective is to get a comprehensive understanding of the spatial distributions, trade-offs, synergies of multiple ecosystem services across the TLB. Our results found that: 1) majority of ecosystem services were clustered in space and had a similar spatial distribution pattern with the geographical resource endowment. Most of the landscape contributed a high supply of no services, one or two, and a low supply of three to seven services. 2) There were high correlation between forest recreation and freshwater supply and regulating services. Aquatic production had low correlation with other services. 3) The changes of provisioning services led to trade-offs between regulating services and cultural services in the TLB, while synergies mainly occurred among the provisioning service. 4) The spatial relationships of multiple services are consistent at 1-km spatial scale, counties and provinces. This research could help integrate multiple ecosystem services across scales and serve as a reference for decision making.

Synergies of carbon neutrality, air pollution control, and health improvement - a case study of China Energy Interconnection scenario

Climate change and air pollution are primarily caused by the combustion and utilization of fossil fuels.Both climate change and air pollution cause health problems.Based on the development of China,it is extremely important to explore the synergies of the energy transition,CO_(2) reduction,air pollution control,and health improvement under the target of carbon peaking before 2030 and carbon neutrality before 2060.This study introduces the policy evolution and research progress related to energy,climate change,and the environment in China and proposes a complete energy-climate-air-health mechanism framework.Based on the MESSAGE-GLOBIOM integrated assessment model,emission inventory and chemical transport model,and exposure-response function,a comprehensive assessment method of energy-climate-air-health synergies was established and applied to quantify the impacts of Chinese Energy Interconnection Carbon Neutrality(CEICN)scenario.The results demonstrate that,by 2060,the SO_(2),NO_(x) and PM_(2.5) emissions are estimated to be reduced by 91%,85%,and 90%respectively compared to the business-as-usual(BAU)scenario.The direct health impacts brought by achieving the goal of carbon neutrality will drive the proactive implementation of more emission reduction measures and bring greater benefits to human health.

Trade-offs and synergies of climate change adaptation strategies among smallholder farmers in sub-Saharan Africa:A systematic review

Climate change adaptation strategies provide a cushion for smallholder farmers,especially in subSaharan Africa against the risks posed by climate hazards such as droughts and floods.However,the decision-making process in climate adaptation is complex.To better understand the dynamics of the process,we strive to answer this question:what are the potential trade-offs and synergies related to decision-making and implementation of climate adaptation strategies among smallholder farmers in sub-Saharan Africa region?A systematic literature review methodology was used through the Preferred Reporting Items for Systematic Review and Meta-Analysis(PRISMA)statement with the four-stage inclusion/exclusion criteria to identify the literature from selected databases(Scopus and Google Scholar).The climate adaptation strategies are organized into five broad categories(crop management,risk management,soil/land management,water management,and livestock management strategies).Evidence suggests that potential trade-offs may arise concerning added costs,additional labor requirements,and competition among objectives or available resources.The synergies,on the other hand,arise from implementing two or more adaptation strategies concurrently in respect of increased productivity,resilience,yield stability,sustainability,and environmental protection.Trade-offs and synergies may also differ among the various adaptation strategies with minimum/zero tillage,comparatively,presenting more tradeoffs.The development and promotion of low-cost adaptation strategies and complementary climate adaptation options that minimize the trade-offs and maximize the synergies are suggested.Skills and knowledge on proper implementation of climate change adaptation strategies are encouraged,especially at the local farm level.

Analysis on synergies and trade-offs in green building development:from the perspective of SDG 11

The 2030 Agenda for Sustainable Development is a prospect for the future development of all countries in the world.Its core is to set up the Sustainable Development Goals for the year of 2030,and develop a series of institutional mechanisms around SDGs to promote its implementation.The SDGs include 17 goals,of which SDG 11 is to make cities and human settlements inclusive,safe,resilient and sustainable.Green building can play a positive role in the implementation of SDG 11.However,the entire process of green building development involves multiple stakeholders and various professional fields,which play different roles where may be positive synergies or negative trade-offs in the whole process.This paper uses the nexus approaches to clarify how multiple stakeholders and professions interact with each other in the green building development with the aim of promoting SDG 11.

An Approach to Developing a Performance Test Based on the Tradeoffs from SW Architectures

In a performance test, the standards for assessing its test results are not sufficiently determined due to the lack of a well-structured test developing methods which are found in a functionality test. By extending the established workflow structure, this approach will concentrate on tradeoffs within T-workflow and further develop tests based on T-workflow. The monitoring and tuning point have also been investigated to understand the validity and performance of software. Finally through a case study, it has been shown that better assessment of software performance can be obtained with the suggested tests developed based on T-workflow and by locating its monitoring point and tuning point.

Physical mechanism of mind changes and tradeoffs among speed,accuracy, and energy cost in brain decision making:Landscape, flux,and path perspectives

Cognitive behaviors are determined by underlying neural networks. Many brain functions, such as learning and memory, have been successfully described by attractor dynamics. For decision making in the brain, a quantitative description of global attractor landscapes has not yet been completely given. Here, we developed a theoretical framework to quantify the landscape associated with the steady state probability distributions and associated steady state curl flux, measuring the degree of non-equilibrium through the degree of detailed balance breaking for decision making. We quantified the decision-making processes with optimal paths from the undecided attractor states to the decided attractor states, which are identified as basins of attractions, on the landscape. Both landscape and flux determine the kinetic paths and speed. The kinetics and global stability of decision making are explored by quantifying the landscape topography through the barrier heights and the mean first passage time. Our theoretical predictions are in agreement with experimental observations： more errors occur under time pressure. We quantitatively explored two mechanisms of the speed-accuracy tradeoff with speed emphasis and further uncovered the tradeoffs among speed, accuracy, and energy cost. Our results imply that there is an optimal balance among speed, accuracy, and the energy cost in decision making. We uncovered the possible mechanisms of changes of mind and how mind changes improve performance in decision processes. Our landscape approach can help facilitate an understanding of the underlying physical mechanisms of cognitive processes and identify the key factors in the corresponding neural networks.

Conversion Synergies during Steam Co-Gasification of Ligno-Cellulosic Simulated Biomass with Coal

Lignin and cellulose chemicals were used as artificial biomass components to make-up a simulated biomass. Alkali and Alkaline Earth Metal (AAEM) as well as volatile matter contents in these chemicals were much different from each other. Co-gasification of coal with simulated biomass shows improved conversion characteristics in comparison to the average calculated from separate conversion of coal and simulated biomass. Two conversion synergetic peaks were observed whereby the first peak occurred around 400℃ while the second one occurred above 800℃. Although co-gasification of coal with lignin that has high AAEM content also shows two synergy peaks, the one at higher temperature is dominant. Co-gasification of coal with cellulose shows only a single synergy peak around 400℃ indicating that synergy at low temperature is related with interaction of volatiles. Investigation of morphology changes during gasification of lignin and coal, suggests that their low reactivity is associated with their solid shape maintained even at high temperature.

Recycling Spent LiCoO_(2)Battery as a High-efficient Lithiumdoped Graphitic Carbon Nitride/Co_(3)O_(4)Composite Photocatalyst and Its Synergistic Photocatalytic Mechanism

The ever-increasing quantity of spent lithium-ion batteries(LIBs)is both a potential environmental pollutant and a valuable resource.The spent LIBs recycling mainly aimed at the separation of valuable elements.Some issues still exist in these processes such as high energy consumption and complex separation procedures.This study avoided element separation and proposed a facile approach to transform spent LiCoO_(2) electrode into a lithium(Li)-doped graphitic carbon nitride(g-C_(3)N_(4))/Co_(3)O_(4) composite photocatalyst through one-pot in situ thermal reduction.During the thermal process,melamine served as the reductant for LiCoO_(2) decomposition and the raw material for g-C_(3)N_(4) production.Li was in situ doped in g-C_(3)N_(4) and the generated Co_(3)O_(4) was in situ integrated,forming a Li-doped g-C_(3)N_(4)/Co_(3)O_(4) composite photocatalyst.This special composite exhibited an enhanced photocatalytic performance,and its photocatalytic H2 production and RhB degradation rates were 8.7 and 6.8 times higher than those of g-C_(3)N_(4).The experiments combined with DFT calculation revealed that such enhanced photocatalytic efficiency was ascribed to the synergy effect of Li doping and Co_(3)O_(4) integrating,which extended the visible light absorption(450-900 nm)and facilitated the charge transfer and separation.This study transforms waste into a high-efficient catalyst,realizing high-valued utilization of waste and environmental protection.

Conjugated polymerized bimetallic phthalocyanine based electrocatalyst with Fe-N_(4)/Co-N_(4) dual-sites synergistic effect for zinc-air battery

The bifunctional oxygen catalyst is essential for zinc-air batteries(ZABs).Here,an efficient bifunctional oxygen catalyst,PPcFeCo/3D-G,is obtained throughπ-πinteraction between the conjugated polymerized iron-cobalt phthalocyanine(PPcFeCo)with excellent thermal stability and three-dimensional graphene(3D-G).The bimetallic synergistic effect of PPcFeCo,verified by DFT(Density functional theory)calculation,andπ-πinteractions enhances the catalytic activity and durability of the PPcFeCo/3D-G.Regarding electrochemical performance,the PPcFeCo/3D-G with a high electron transfer number(3.98,@0.768 V vs.RHE)has excellent half-wave potential(E_(1/2)=0.890 V vs.RHE)and exhibits outstanding reversibility(ΔE=0.700 V,ΔE=Ej=10-E_(1/2)).The liquid ZAB(LZAB)employed PPcFeCo/3D-G displays a high power density(222 m W cm^(-2)),a specific capacity(792 m A h g-1),and excellent durability(120 h).This work has guiding significance for the preparation of high-efficiency bifunctional catalysts.