Exploration and Practice of Precision Emission Reduction Monitoring System in Air Pollution Prevention and Control in a District of Tianjin

At present,China’s atmospheric environmental protection work has achieved initial results,but environmental protection is facing increasing pressure,and the environmental situation is still not optimistic.In response to the call of the state,efforts have been intensified in environmental protection and ecological civilization construction,and supply-side structural reform has been actively promoted,and the Implementation Plan for Tianjin’s Comprehensive Discharge of Industrial Pollution Sources to Meet Standards has been promoted.When the total amount of pollutants discharged in key areas far exceeds the environmental capacity,regional heavy pollution weather will still occur once adverse meteorological conditions are encountered.In accordance with the Law of the People’s Republic of China on the Prevention and Control of Atmospheric Pollution,when the deterioration of air quality to a certain extent,to protect public health,key gas related industries should carry out emergency emission reduction in accordance with the local emergency plan while the local government starts the emergency response of heavy pollution weather.Direct economic loss of emergency response to heavy pollution weather is enormous.On the basis of meeting the total amount of emissions required by the state,the project aims to achieve the effect of"emission reduction and production increase"by precise emission reduction according to local characteristics.

Co/CoO heterojunction rich in oxygen vacancies introduced by O2 plasma embedded in mesoporous walls of carbon nanoboxes covered with carbon nanotubes for rechargeable zinc-air battery

Herein,Co/CoO heterojunction nanoparticles(NPs)rich in oxygen vacancies embedded in mesoporous walls of nitrogen-doped hollow carbon nanoboxes coupled with nitrogen-doped carbon nanotubes(P-Co/CoOV@NHCNB@NCNT)are well designed through zeolite-imidazole framework(ZIF-67)carbonization,chemical vapor deposition,and O_(2) plasma treatment.As a result,the threedimensional NHCNBs coupled with NCNTs and unique heterojunction with rich oxygen vacancies reduce the charge transport resistance and accelerate the catalytic reaction rate of the P-Co/CoOV@NHCNB@NCNT,and they display exceedingly good electrocatalytic performance for oxygen reduction reaction(ORR,halfwave potential[EORR,1/2=0.855 V vs.reversible hydrogen electrode])and oxygen evolution reaction(OER,overpotential(η_(OER,10)=377mV@10mA cm^(−2)),which exceeds that of the commercial Pt/C+RuO_(2) and most of the formerly reported electrocatalysts.Impressively,both the aqueous and flexible foldable all-solid-state rechargeable zinc-air batteries(ZABs)assembled with the P-Co/CoOV@NHCNB@NCNT catalyst reveal a large maximum power density and outstanding long-term cycling stability.First-principles density functional theory calculations show that the formation of heterojunctions and oxygen vacancies enhances conductivity,reduces reaction energy barriers,and accelerates reaction kinetics rates.This work opens up a new avenue for the facile construction of highly active,structurally stable,and cost-effective bifunctional catalysts for ZABs.

Nitrogen-doped carbon nanotube encapsulating cobalt nanoparticles towards efficient oxygen reduction for zinc–air battery

Nitrogen-doped carbon materials encapsulating 3 d transition metals are promising alternatives to replace noble metal Pt catalysts for efficiently catalyzing the oxygen reduction reaction(ORR). Herein, we use cobalt substituted perfluorosulfonic acid/polytetrafluoroethylene copolymer and dicyandiamide as the pyrolysis precursor to synthesize nitrogen-doped carbon nanotube(N–CNT) encapsulating cobalt nanoparticles hybrid material. The carbon layers and specific surface area of N–CNT have a critical role to the ORR performance due to the exposed active sites, determined by the mass ratio of the two precursors. The optimum hybrid material exhibits high ORR activity and stability, as well as excellent performance and durability in zinc–air battery.

Preparation and properties of transition metal nitrides caged in N-doped hollow porous carbon sphere for oxygen reduction reaction

A series of transition metal nitrides(MxNy,M=Fe,Co,Ni)nanoparticle(NP)composites caged in N-doped hollow porous carbon sphere(NHPCS)were prepared by impregnation and heat treatment methods.These composites combine the high catalytic activity of nitrides and the high-efficiency mass transfer characteristics of NHPCS.The oxygen reduction reaction results indicate that Fe2N/NHPCS has the synergistic catalytic performance of higher onset potential(0.96 V),higher electron transfer number(~4)and higher limited current density(1.4 times as high as that of commercial Pt/C).In addition,this material is implemented as the air catalyst for zinc−air battery that exhibits considerable specific capacity(795.1 mA·h/g)comparable to that of Pt/C,higher durability and maximum power density(173.1 mW/cm2).

Co_(2)N Nanoparticles Anchored on N-Doped Active Carbon as Catalyst for Oxygen Reduction Reaction in Zinc–Air Battery

The development of efficient catalytic electrode toward oxygen reduction reaction(ORR)is still a great challenge for the wide use of zinc–air batteries.Herein,Co_(2)N nanoparticles(NPs)anchored on N-doped carbon from cattail were verified with excellent catalytic performances for ORR.The onset and half-wave potentials over the optimal catalyst reach to 0.96 V and 0.84 V,respectively.Current retention rates of 96.8%after 22-h test and 98.8%after running 1600 s were obtained in 1 M methanol solution.Density functional theory simulation proposes an apparently increased electronic states of Co_(2)N in N-doped carbon layer close to the Fermi level.Higher charge density,favorable adsorption,and charge transfer of intermediates originate from the coexistence of Co_(2)N NPs and N atoms in carbon skeleton.The superior catalytic activity of composites also was confirmed in zinc–air batteries.This novel catalytic property and controllable preparation approach of Co_(2)Ncarbon composites provide a promising avenue to fabricate metal-containing catalytically active carbon from biomass.

Exploration of Market Mechanism on Controlling Air Pollution and Carbon Emissions in China

Based on increasingly grim situation of carbon emissions in China,air pollution control and carbon emission reduction are very important. Therefore,combining with China’s specific national conditions,we should explore the market mechanisms to control air pollution and reduce carbon emissions in China. The achievement of the carbon emission reduction purpose needs to establish the carbon trade market based on intensity emission reduction and suitable for China’s national conditions. By setting the cross-industry,cross-region and cross-time carbon trade scenarios in China,this paper tries to study the market mechanism of carbon intensity trade among industries and regions and based on carbon finance mechanism.

The Policy of Energy Saving,Pollution Control and Carbon Reduction based on the Cause Analysis of“Power Restriction”Event

In recent years,the“power restriction”measures were taken in many localities,industrial electricity consumption was interrupted,mainly in the“two high”(high energy consumption and high pollutant emission)enterprises.Take the“power restriction”event in 2021 as an example,this event affected a wide range of regions and disrupted people’s livelihood.It not only refers to the power switch and rationing measures taken by individual regions,but also includes differentiated policies implemented by over 20 provinces to limit power supply and industrial production.This paper investigated in detail and summarized the different requirements of power restriction across the country,through the comparison of annual growth rates of power generation and industrial added value,the comparison results of energy intensity,electricity production,power consumption and the industrial growth rate in each province are analyzed.Industrial enterprises and related industrial chains were most heavily affected by the“power restriction”event,mainly in steel,cement,electrolytic aluminum,industrial silicon,textile printing and dyeing,chemical fiber,chemical and other enterprises with high energy consumption and high pollutants emission.The measures to limit electricity will affect the normal production of enterprises to a certain extent,leading to not only the decrease of production efficiency,but also the increase of energy consumption and pollutant emission per unit product.Energy management measures such as differentiated electricity price have limited effect on the output of“two high”industrial products,and the economic leverage of differentiated electricity price is gradually being diluted by the price rise of end products.This paper analyzed the reasons and explored several key problems that need special attention.then recommended certain countermeasures for its appropriate application in the future.

Cerium-tungsten oxides supported on activated red mud for the selective catalytic reduction of NO_(x)

Activated red mud(RM)has been proved to be a promising base material for the selective catalysis reduction(SCR)of NOx.The inherent low reducibility and acidity limited its low-temperature activity.In this work,molybdenum oxide,tungsten oxide,and cerium oxide were used to reconfigure the redox sites and acid sites of red mud based catalyst.When activated red mud was reconfigured by cerium-tungsten oxide(Ce-W@RM),the NOx conversion kept above 90%at 219-480℃.The existence of Ce^(3+)/Ce^(4+) redox electron pairs provided more surface adsorbed oxygen(O_(α)) and served as a redox cycle.Positive interactions between Ce,W species and Fe oxide in red mud occurred,which led to the formation of unsaturated chemical bond and promoted the activation of adsorbed NH_(3) species.WO_(3) and Ce_(2)(WO_(4))_(3)(formed by solid-state reaction between Ce and W species)could provide more Brønsted acid sites(W-O modes of WO_(3),W=O or W-O-W modes of Ce_(2)(WO_(4))_(3)).CeO_(2) species could provide more Lewis acid sites.The Langmuir-Hinshelwood(L-H)routes and Eley-Rideal(E-R)routes occurred in the low-temperature SCR reaction on the Ce-W@RM surface.NH_(4)^(+) species on Brønsted acid sites,NH_(3) species on Lewis acid sites,bidentate nitrate and bridging nitrate species were key active intermediates species.

Hierarchical N-Doped Porous Carbons for Zn–Air Batteries and Supercapacitors

Nitrogen-doped carbon materials with a large specific surface area,high conductivity,and adjustable microstructures have many prospects for energy-related applications.This is especially true for N-doped nanocarbons used in the electrocatalytic oxygen reduction reaction(ORR)and supercapacitors.Here,we report a low-cost,environmentally friendly,large-scale mechanochemical method of preparing N-doped porous carbons(NPCs)with hierarchical micro-mesopores and a large surface area via ball-milling polymerization followed by pyrolysis.The optimized NPC prepared at 1000°C(NPC-1000)offers excellent ORR activity with an onset potential(Eonset)and half-wave potential(E1/2)of 0.9 and 0.82 V,respectively(vs.a reversible hydrogen electrode),which are only approximately 30 mV lower than that of Pt/C.The rechargeable Zn–air battery assembled using NPC-1000 and the NiFe-layered double hydroxide as bifunctional ORR and oxygen evolution reaction electrodes offered superior cycling stability and comparable discharge performance to RuO2 and Pt/C.Moreover,the supercapacitor electrode equipped with NPC prepared at 800℃ exhibited a high specific capacity(431 F g^−1 at 10 mV s^−1),outstanding rate,performance,and excellent cycling stability in an aqueous 6-M KOH solution.This work demonstrates the potential of the mechanochemical preparation method of porous carbons,which are important for energy conversion and storage.

Energy Saving and Emission Reduction Estimations of Electrified Railways in China

Based on the annual production data collected by the Statistic Center of the Ministry of Railways of the People＇s Republic of China, we calculated the energy saving and direct emission reductions of CO2, soot, SO2, CO, NOx and CnHm of electrified railways, and analyzed their dynamic characteristics during the period of 1975 2007. The results show that during this period, the annual mean values of energy saving is 1.23×10^6 tce, and direct emission reduction of CO2, soot, SO2, CO, NOx and CnHm are 4.267×10^6 t, 20.5×10^3 t, 3.0×10^3 t, 9.6×10^3 t, 67.9×10^3 t, and 6.9×10^3 t per year, respectively. The annual average increasing rates of energy saving is 139×10^3 tce, and direct emission reduction of CO2, soot, SO2, CO, NOx and CnHm are 483×10^3 t, 2.3×10^3 t, 0.34×10^3 t, 1.1×10^3 t, 7.7 ×10^3 t and 0.78×10^3 t per year, respectively. The electrified railways have played an important role in decreasing the energy consumption and air pollutant emissions of China＇s railway system. The results of this study could provide some reference knowledge for future reductions of energy consumption and waste gas emission in China＇s railway transportation.

Nitrogen-doped mesoporous carbon nanospheres loaded with cobalt nanoparticles for oxygen reduction and Zn–air batteries

Mesoporous carbon supported with transition metals nanoparticles performs desired activities for oxygen reduction reaction(ORR) and clean energy conversion devices such as Zn–air batteries. In this work,we synthesized N-doped mesoporous carbon loaded with cobalt nanoparticles(CoMCN) through selfassembly method. There are sufficient mesopores on the carbon substrate which stem from the poreforming agent. These mesopores can provide enough accessible active sites and profitable charge/mass transport for ORR. The high content of pyridinic and graphitic N is beneficial for promoting O_(2) adsorption and reduction. The smaller value of ID/IGindicates the higher degree of graphitization of CoMCN,providing better electronic conductivity. The half-wave potential of CoMCN is 0.865 V in basic solution,which is 24 mV more positive than that of the commercial Pt/C(0.841 V). In addition, CoMCN performs excellent methanol tolerance and stability under both basic and acidic conditions. The Zn–air battery assembled with CoMCN performs the larger power density and open-circuit voltage than the commercial Pt/C-based battery, indicating the potential application in energy conversion systems. This work provides thoughtful ideas for fabricating transition metal nanoparticles based porous carbon for electrocatalysis and metal–air batteries.

Alkali-resistant NO_(x) reduction over FeVO_(4)/TiO_(2)catalysts via regulating the electron transfer between Fe and V

The presence of alkali metals in exhaust gas from stationary resources causes a grand challenge for the practical application of selective catalytic reduction(SCR)of NO_(x) with NH_(3).Here,alkali-resistant NO_(x) reduction has been successfully implemented via tailoring the electron transfer over Fe and V species on FeVO_(4)/TiO_(2)catalysts.The strong interaction between Fe and V induced electron transfer from V to Fe and strengthened the adsorption and activation of NH_(3)and NO over active VO_(x) sites.In the presence of K_(2)O,the strong electron withdrawing effect of Fe offset the electron donating effect of K on the VO_(x) species,thus protecting the active species VO_(x) to maintain the NO_(x) reduction ability.The enhanced adsorption and activation of NH_(3) allowed SCR reaction to proceed via E-R mechanism even after K_(2)O poisoning.This work elucidated the electronic effects on the alkali metals resistance of traditional ferric vanadate SCR catalysts and provided a promising strategy to design SCR catalysts with superior alkali resistance.

NO_(x) reduction against alkali poisoning over Ce(SO_(4))_(2)-V_(2)O_(5)/TiO_(2) catalysts by constructing the Ce^(4+)-SO_(4)^(2−)pair sites

Commercial V_(2)O_(5)-based catalysts have been successfully applied in NH_(3) selective catalytic reduction(NH_(3)-SCR)of NO_(x) from power stations,but their poor alkali-resistance restrains the wider application in nonelectrical industries.In this study,NO_(x) reduction against alkali poisoning over V_(2)O_(5)/TiO_(2) is greatly improved via Ce(SO_(4))_(2) modification.It has been originally demonstrated that Ce^(4+)-SO_(4)^(2−)pair sites play crucial roles in improving NO_(x) reduction against alkali poisoning over V_(2)O_(5)/TiO_(2) catalysts.The strong interaction between V species and Ce sites of Ce^(4+)-SO_(4)^(2−)pairs triggers the reaction between NH_(4)^(+) species and gaseous NO via Eley-Rideal(E-R)reaction pathway.After K-poisoning,the SO_(4)^(2−)sites of Ce^(4+)-SO_(4)^(2−)pairs as protective sites strongly bond with K and thus maintain the high reaction efficiency via the E-R reaction pathway.This work demonstrates an effective strategy to enhance NO_(x) reduction against alkali poisoning over catalysts via constructing Ce^(4+)-SO_(4)^(2−)pair sites,contributing to developing alkali-resistant SCR catalysts for practical application in nonelectrical industries.

Graphitic‐shell encapsulated FeNi alloy/nitride nanocrystals on biomass‐derived N‐doped carbon as an efficient electrocatalyst for rechargeable Zn‐air battery

Oxygen reduction/evolution reactions(ORR/OERs)catalysts play a key role in the metal‐air battery and water‐splitting process.Herein,we developed a facile template‐free method to fabricate a new type of non–noble metal‐based hybrid catalyst which consists of binary FeNi alloy/nitride nanocrystals with graphitic‐shell and biomass‐derived N‐doped carbon(NC)(FexNiyN@C/NC).This novel nanostructure exhibits superior performance for ORR/OER,which can be attributed to the strong interactions between the graphitic‐shell encapsulated FeNi alloy/nitride nanocrystals and the N‐doped porous carbon substrate.The X‐ray absorption spectroscopy technique was employed to reveal the underlying mechanisms for the excellent performance.The assembled Zn‐air battery device exhibits outstanding charging/discharging performance and cycling stability,indicating the great potential of this type of novel catalysts.

Hollow cobalt oxide nanoparticles embedded in nitrogen-doped carbon nanosheets as an efficient bifunctional catalyst for Zn–air battery

Rational design of low-cost, highly electrocatalytic activity, and stable bifunctional electrocatalysts for oxygen reduction reaction(ORR) and oxygen evolution reaction(OER) has been a great significant for metal–air batteries. Herein, an efficient bifunctional electrocatalyst based on hollow cobalt oxide nanoparticles embedded in nitrogen-doped carbon nanosheets(Co/N-Pg) is fabricated for Zn–air batteries. A lowcost biomass peach gum, consisting of carbon, oxygen, and hydrogen without other heteroatoms, was used as carbon source to form carbon matrix hosting hollow cobalt oxide nanoparticles. Meanwhile, the melamine was applied as nitrogen source and template precursor, which can convert to carbon-based template graphitic carbon nitride by polycondensation process. Owing to the unique structure and synergistic effect between hollow cobalt oxide nanoparticles and Co-N-C species, the proposal Co/N-Pg catalyst displays not only prominent bifunctional electrocatalytic activities for ORR and OER, but also excellent durability. Remarkably, the assembled Zn–air battery with Co/N-Pg air electrode exhibited a low discharge-charge voltage gap(0.81 V at 50 mA cm^-2) and high peak power density(119 mW cm^-2) with long-term cycling stability. This work presents an effective approach for engineering transition metal oxides and nitrogen modified carbon nanosheets to boost the performance of bifunctional electrocatalysts for Zn–air battery.

Bead-like cobalt-nitrogen co-doped carbon nanocage/carbon nanofiber composite:A high-performance oxygen reduction electrocatalyst for zinc-air batteries

Proper regulation of metal-nitrogen carbon(M-N-C)materials derived from zeolitic imidazolate frameworks(ZIFs)is essential to enhance the oxygen reduction reaction(ORR)performance.However,most of the reports focus on the component regulation,and the structure regulation of ZIFs-derived M-N-C materials by a simple preparation method has been barely reported.Herein,using a one-step electrospinning method with subsequent pyrolysis,we have prepared a bead-like cobalt-nitrogen co-doped carbon nanocage/carbon nanofiber(Co-N-C/CNF)composite electrocatalyst with the porous carbon nanocages arranged one by one in the highly conductive carbon nanofibers.Profiting from the fully exposed active sites and improved conductivity,the Co-NC/CNF catalyst exhibits an excellent ORR performance even surpassing the commercial Pt/C catalyst.Density functional theory(DFT)results demonstrate that the CoNP-N1-C2 active sites on Co-N-C/CNF make the core contribution to the improvement of ORR properties.Moreover,the zinc-air battery(ZAB)based on the Co-N-C/CNF catalyst also shows outstanding discharge performance.This study provides a new strategy for the preparation and structural design for ZIFs-derived M-N-C materials as efficient ORR catalysts.

京津冀地区大气污染物与二氧化碳的协同减排分析

推进减污降碳协同增效成为社会经济高质量发展的客观要求。基于协同控制效应坐标系、单指标协同减排弹性和协同减排协同度等多维度协同减排分析方法,对2013—2019年京津冀地区CO_(2)排放量与SO_(2)、NO_(x)、烟粉尘的排放特征和协同减排水平进行综合评价。结果表明:(1)近年来,京津冀地区的CO_(2)排放量整体上处于增长的平台期,三类大气污染物(SO_(2)、NO_(x)、烟粉尘)实现了不同程度的减排,然而与全国对比,京津冀地区减污降碳协同增效工作仍面临较大压力。(2)京津冀地区CO_(2)与SO_(2)、NO_(x)和烟粉尘三类大气污染物之间存在不连续的协同减排年份、不稳定的协同减排交叉弹性、中低程度的耦合协同度,反映了该区域协同减排程度均处于较低水平,尚未形成稳定的减污降碳协同增效状态。在绿色低碳高质量发展目标引领下,提出如下建议:(1)加快推动污染末端治理向源头治理转变,从源头上实现产业发展和能源消费的低碳化。(2)将产业结构优化作为推进京津冀减污降碳的主要途径,统筹规划项目布局和产能分配。(3)发展能源替代和节能减排,优化调整京津冀的能源消费结构。

“双碳”目标下“减污降碳协同增效”在生态环境法典中的立法表达

我国生态环境法典编纂既要实现环境立法的体系化,也要吸纳生态文明体制机制改革制度成果,为我国的“双碳”战略提供法治保障。实现“双碳”目标,“降碳”是战略方向,“减污降碳协同增效”是重点路径。“双碳”法治建设应秉持整体论法治理念、重视调整对象的关联性、彰显治理制度的协同性。现行减污降碳法律规范体系未确立减污降碳协同治理的整体性法治理念,未将温室气体排放作为调整对象,减污降碳协同治理制度阙如,亟待予以针对性制度创新,同时也要回应减污降碳协同效应的多层次复合关系。生态环境法典污染控制编应从更新立法理念、完善污染控制一般制度和大气污染控制专章制度等方面实现减污降碳协同治理的制度创新。

减污降碳协同效应的生成逻辑、内涵阐释与实现方略

实现减污降碳协同效应是实现“双碳”目标愿景、推进美丽中国建设的重要内容。立足理论逻辑和历史逻辑,深刻阐明减污降碳协同效应的生成逻辑;基于经济高质量发展与生态环境治理要求,系统阐释减污降碳协同效应的深刻内涵;围绕协同推进减污降碳的现实挑战,对减污降碳协同效应的实现方略进行探讨。研究发现:对环境污染物和碳排放同根同源同过程特性的系统性认识、中国环境污染治理工作与应对气候变化行动的开展为减污降碳协同效应创造了坚实的实现基础。减污降碳协同效应源自协同学理论与国际绿色低碳发展实践的结合,其核心在于推进经济社会发展绿色转型,以兼顾实现经济高质量发展与解决生态环境治理问题,增加经济增长绿色动能,全面提高生态环境治理综合效益。面向全面建设社会主义现代化国家的新征程,须切实健全减污降碳协同治理制度、培育拓展生态环境市场、推动减污降碳科技协同创新,建设减污降碳协同治理体系,推动实现减污降碳协同效应。

“双碳”背景下减污降碳协同治理的法治保障研究——结构功能主义的分析视角

实现碳达峰碳中和是一场广泛而深刻的经济社会系统性变革,同时也对中国国家治理体系和治理能力提出了新要求。综合考量中国当下生态环境和经济发展的现实情况,温室气体和环境污染物的产生具有一定的同源性,“以实现减污降碳协同增效为总抓手”具有合理性和科学性。从结构功能主义视角看,减污降碳协同治理的法治保障关涉价值理念、立法、法律实施以及多元参与四个维度。从法律的规范逻辑出发,以结构功能主义分析方法为进路,强调系统思维,借助AGIL图式分析,从纵向分化与横向交换两个维度全面检视减污降碳协同治理存在的架构缺失、功能离散、动力不足等问题;整合减污降碳协同治理中相互分离的社会实体,在明确绿色低碳原则、效能原则、综合调整原则的基础上,构建减污降碳协同治理的法律和政策体系,健全刚柔兼济的法律实施机制,推进建立网格化多元共治格局,以期为减污降碳协同增效的实现提供法治保障。