Electrochemical reduction of CO_2 in solid oxide electrolysis cells

The effort on electrochemical reduction of COto useful chemicals using the renewable energy to drive the process is growing fast recently. In this review, we introduce the recent progresses on the electrochemical reduction of COin solid oxide electrolysis cells（SOECs）. At high temperature, only CO is produced with high current densities and Faradic efficiency while the reactor is complicated and a better sealing technique is urgently needed. The typical electrolytes such as zirconia-based oxides, ceria-based oxides and lanthanum gallates-based oxides, anodes and cathodes are introduced in this review, and the cathode materials, such as conventional metal–ceramics（cermets）, mixed ionic and electronic conductors（MIECs） are discussed in detail. In the future, to gain more value-added products, the electrolyte, cathode and anode materials should be developed to allow SOECs to be operated at temperature range of 573–873 K. At those temperatures, SOECs may combine the advantages of the low temperature system and the high temperature system to produce various products with high current densities.

Detrimental phase evolution triggered by Ni in perovskite-type cathodes for CO2 electroreduction

Perovskite oxides are popular as cathode materials of solid oxide electrolysis cells, because of their good redox stability and high resistance to coke formation.Unexpectedly, a negative effect of Ni doping is found on Sr2Fe(1.5-x)NixMo(0.5)O(x = 0, 0.05, 0.1, 0.2) cathode for pure CO2 electroreduction at 800 ℃, although Ni is highly active for CO2 electroreduction.The CO2 electroreduction performance degrades with the increase of Ni doping amount.Various characterization techniques are used to disclose the negative effect.Ni doping decreases the perovskite stability under electroreduction conditions, Fe and Ni cations in the B-site are reduced to metal nanoparticles and SrCO3 forms on the surface of the perovskite.The phase instability results from the weaker Ni–O bond.Although the Fe-Ni nanoparticles are in favor of the CO2 electroreduction, too much SrCO3 and carbon deposition block the charge transfer and diffusion of oxygenous species on the cathode surface.

Urban food-energy-water nexus:a case study in Beijing

Food,energy and water(FEW)are indispensable,irreplaceable and safeguarding resources with tangled interlinkages among each other,often framed in terms of‘nexus’.Cities have become the bustling hubs of resource consumption and production,facing the most intense stress.Globally,food security,fresh water shortage and fossil energy exhaustion have become the greatest challenge for the sustainable development of cities in the future.Systematic analysis and simulation of dynamic evolution of urban FEW demand and supply and its nexus would add significant and practical value for macro-management such as ensuring the security of urban resource.Taking Beijing as the case study,we established a dynamic model for the FEW demand and supply from the perspective of cross-ectoral and cross-regional nexus with the Stella modelling platform,then it was run for simulating the dynamic changes and nexus characteristics of FEW during the interval between 2016 and 2035.The results showed that:①The gap between local production and demand of these three resources in Beijing will continue to increase.In 2035,Beijing will need 2.16 million tons of grain,0.83 million tons of meat,4.6 billion m3 of water and 91.65 million tons of standard coal of energy while the resources produced and supplied by locality independently will be 0.21 million tons,0.23 million tons,3.3 billion cubic meters and 16.5 million tons of standard coal respectively.Beijing has to draw on cross-boundary production to meet FEW-use with the increasing gap between local supply and demand.②There is a developing trend of the absolute quantity of interaction among FEW.Structurally,the‘outsourcing’feature is obvious and the indigenous nexus links of three resources are shifting to back-end supply chain such as transportation and treatment.③The change of nexus indexes are mainly affected by the mutual and strong dependence between food and water.Food and energy depend more and more on each other;in contrast,the inter-relationship between water and energy is more stable.In addition,inter-regional FEW nexus is strengthened.④To improve systematic management of urban resources,we need to capture multi-tradeoffs of the FEW system comprehensively and establish a multi-regional and multi-factor integrated and collaborative resource management mechanism.

Nicotine and menthol independently exert neuroprotective effects against cisplatin-or amyloid-toxicity by upregulating Bcl-xl via JNK activation in SH-SY5Y cells

Nicotine and menthol,agonists of nicotinic acetylcholine receptor(nAChR)and transient receptor potential melastatin type 8(TRPM8),serve important roles in the prevention of cell death-involved neurodegenerative diseases.However,the potential synergistic effects of nicotine and menthol on anti-apoptotic ability are still uncertain.In the present study,the potential synergistic effects of nicotine and menthol on cisplatin or amyloidβ1-42 induced cell model of the neurodegenerative diseases were explored by assessing cell viability,TNF-αexpression,caspase-3 activation,and the collapse of mitochondrial membrane potential in human SH-SY5Y neuroblastoma cells.Statistical significance was tested using Student’s t-test or one-way ANOVA with post hoc Newman-Keuls test.The results showed that:Firstly,SH-SY5Y cell viability was obviously increased by the treatments with nicotine and menthol.Secondly,nicotine and menthol independently alleviated cisplatin or amyloidβ1-42 induced TNF-αup-regulation.Thirdly,nicotine and menthol abrogated the effect of cisplatin and amyloidβ25-35 on caspase-3 activation.Interestingly,the effect of cisplatin and amyloidβ1-42 on the collapse of mitochondrial membrane potential was efficiently attenuated by nicotine and menthol treatments.Most importantly,the inhibition of c-jun kinase(JNK)activation abolished the effect of cisplatin,and amyloidβ1-42 stimulated Bcl-xl expression.All these findings indicate that nicotine and menthol independently exert neuroprotective effects by upregulating Bcl-xl via JNK activation.Nicotine and menthol augmented Bcl-xl expression and JNK phosphorylation,and thus they are potential therapeutic targets for altering the progress of neurodegenerative diseases.

Evaluating the Conservation Efforts of Multi-Projects Using Remote Sensing and Light Use Efficiency Model: A Case of Nyungwe Forest National Park, Rwanda

This paper investigates the effectiveness of conservation efforts in the Nyungwe Forest National Park (Nyungwe). The forest is one of the six key landscapes identified for conservation in the Albertine Rift because it hosts many threatened species. As such, a number of different stakeholders have been involved in its conservation since 1987;yet, studies that emphasize and evaluate the success of these conservation efforts are limited. We combined a rapid and relatively low cost remotely-sensed data and the Light Use Efficiency model to generate forest conservation indicators such as NDVI, forest canopy Net Primary Productivity and carbon sequestered from 1986 to 2010. The influence of topographic and climatic factors on these indicators was examined. The supervised classifier was used to catalogue the area into Forest, Wetland, and Bareland. The forest was the major category (above 90%) of Nyungwe relative to wetland and bareland. Based on degradation intensity, two distinctive periods were realised;the first period spans 8 years (1986-1994) whereas the second spans 16 years (1994-2010). The former degradation intensity period is 10 times higher than the latter period. Although the size of forest recovered up to 90%, the daily NPP and carbon sequestration capacity decreased by 37.1% (i.e. NPP 6.5 Mg tons in 1986 to 4.1 Mg tons in 2010). Areas of the forest that are physically constrained (high altitude) had a higher degradation. Guided by our indicators, there is an overall success in conservation efforts, but efforts were mostly concentrated in accessible areas. Therefore, conservation efforts that aim to respond to degradation of the inaccessible areas of the forest should be stressed in the management plan of the park.

NASICONs-type solid-state electrolytes:The history,physicochemical properties,and challenges

Solid-state electrolytes are critical for the development of next-generation high-energy and high-safety rechargeable batteries.Among all the candidates,sodium(Na)superionic conductors(NASICONs)are highly promising because of their evident advantages in high ionic conductivity and high chemical/electrochemical stability.The concept of NASICONs was proposed by Hong and Goodenough et al.in 1976 by reporting the synthesis and characterization of Na1+xZr2(SixP3−x)O12(0≤x≤3),which has attracted tremendous attention on the NASICONs-type solid-state electrolytes.In this review,we are committed to describing the development history of NASICONs-type solid-state electrolytes and elucidating the contribution of Goodenough as a tribute to him.We summarize the correlations and differences between lithium-based and sodium-based NASICONs electrolytes,such as their preparation methods,structures,ionic conductivities,and the mechanisms of ion transportation.Critical challenges of NASICONs-structured electrolytes are discussed,and several research directions are proposed to tackle the obstacles toward practical applications.

面向可持续发展的资源关联研究:现状与展望

中国传统文化认为“金、木、水、火、土”五行相生相克,这是最早描述物质要素之间相互关联的系统性学说.在现代科学语境中,支撑和制约可持续发展的关键自然资源主要包括矿产资源、生物质资源、水资源、能源和土地资源,大致与“五行”对应.它们之间存在广泛的依赖、替代、竞争和互补关系.近10年来,全球兴起了“资源关联”(resources nexus)的研究热潮.本文对资源关联研究进行了文献计量分析,综述了常用研究方法、模型和数据,分析了资源关联的驱动力、影响因素及其对社会经济可持续发展的作用.主要发现如下:(1)日益紧密的资源关联关系对可持续发展的影响不断增强;(2)全球化驱使资源关联由区域性向全球性开放系统延伸;(3)资源关联使可持续发展目标之间既存在协同也存在冲突;(4)资源关联对社会经济可持续发展转型既有促进也有制约作用.未来可以在四方面深化该领域的研究:(1)拓展资源关联的研究范畴;(2)揭示资源关联的内在机制及其影响;(3)构建通用、开放、共享、可拓展的数据平台;(4)加强资源关联研究的可持续发展决策支撑能力.

Cost of non-renewable energy in production of wood pellets in China

Assessing the extent to which all bio-fuels that are claimed to be renewable are in fact renewable is essential because producing such renewable fuels itself requires some amount of non-renewable energy （NE） and materials. Using hybrid life cycle analysis （LCA）--from raw material collection to delivery of pellets to end users--the energy cost of wood pellet production in China was estimated at 1.35 J/J, of which only 0.09 J was derived from NE, indicating that only 0.09 J of NE is required to deliver 1 J of renewable energy into society and showing that the process is truly renewable. Most of the NE was consumed during the conversion process （46.21%） and delivery of pellets to end users （40.69%）, during which electricity and diesel are the two major forms of NE used, respectively. Sensitivity analysis showed that the distance over which the pellets are transported affects the cost of NE significantly. Therefore the location of the terminal market and the site where wood resources are available are crucial to saving diesel.

Enhancing the green efficiency of fundamental sectors in China’s industrial system:A spatial-temporal analysis

Due to sectoral interactions in the economy,the overall green efficiency(GE)of China’s industrial system relies heavily on fundamental sectors that contribute substantial energy to the supply chain production of other sectors but shows low sectoral GE.For the three fundamental sectors in China’s industrial systems,namely the smelting and pressing of nonferrous metals(SPNFM),the processing of petroleum,coking,and nuclear fuel(PPCNF);and the manufacturing of nonmetallic mineral products(MNMMP),we employed a three-stage data envelopment analysis(DEA)model to measure GE in the fundamental sectors in 30 provinces from 2010 to 2015.We then adopted a stochastic frontier analysis(SFA)model to evaluate the influence of technological innovation(TI),industrial agglomeration(IA),environmental regulation(ER),and intraindustry competition(IC).The results showed that GE in the three fundamental sectors varied spatially.Specifically,TI promoted GE in MNMMP,but the effect was not obvious in the SPNFM and PPCNF sectors.Moreover,ER had positive impacts on GE in the fundamental sectors.The effects of IA and IC on GE in the fundamental sectors varied in direction and strength.After eliminating the impacts of environmental effects and statistical noise,the real GE in the three fundamental sectors varied significantly compared to the comprehensive GE.Policy opportunities for enhancing GE in the fundamental sectors mainly lie in region-specific policy and regulations that avoid a“one-size-fits-all”governance approach.