Co_(3)O_(4)as an efficient passive NO_(x) adsorber for emission control during cold-start of diesel engines

The Co_(3)O_(4)nanoparticles,dominated by a catalytically active(110)lattice plane,were synthesized as a low-temperature NO_(x) adsorbent to control the cold start emissions from vehicles.These nanoparticles boast a substantial quantity of active chemisorbed oxygen and lattice oxygen,which exhibited a NO_(x) uptake capacity commensurate with Pd/SSZ-13 at 100℃.The primary NO_(x) release temperature falls within a temperature range of 200-350℃,making it perfectly suitable for diesel engines.The characterization results demonstrate that chemisorbed oxygen facilitate nitro/nitrites intermediates formation,contributing to the NO_(x) storage at 100℃,while the nitrites begin to decompose within the 150-200℃range.Fortunately,lattice oxygen likely becomes involved in the activation of nitrites into more stable nitrate within this particular temperature range.The concurrent processes of nitrites decomposition and its conversion to nitrates results in a minimal NO_(x) release between the temperatures of 150-200℃.The nitrate formed via lattice oxygen mainly induces the NO_(x) to be released as NO_(2) within a temperature range of 200-350℃,which is advantageous in enhancing the NO_(x) activity of downstream NH_(3)-SCR catalysts,by boosting the fast SCR reaction pathway.Thanks to its low cost,considerable NO_(x) absorption capacity,and optimal release temperature,Co_(3)O_(4)demonstrates potential as an effective material for passive NO_(x) adsorber applications.

Recent progress on the recycling technology of Li-ion batteries

Lithium-ion batteries(LIBs)have been widely applied in portable electronic devices and electric vehicles.With the booming of the respective markets,a huge quantity of spent LIBs that typically use either LiFePO_(4) or Li N_(x)Co_(y)Mn_(z)O_(2) cathode materials will be produced in the very near future,imposing significant pressure for the development of suitable disposal/recycling technologies,in terms of both environmental protection and resource reclaiming.In this review,we firstly do a comprehensive summary of the-state-of-art technologies to recycle Li N_(x)Co_(y)Mn_(z)O_(2) and LiFePO_(4)-based LIBs,in the aspects of pretreatment,hydrometallurgical recycling,and direct regeneration of the cathode materials.This closed-loop strategy for cycling cathode materials has been regarded as an ideal approach considering its economic benefit and environmental friendliness.Afterward,as for the exhausted anode materials,we focus on the utilization of exhausted anode materials to obtain other functional materials,such as graphene.Finally,the existing challenges in recycling the LiFePO_(4) and Li N_(x)Co_(y)Mn_(z)O_(2) cathodes and graphite anodes for industrial-scale application are discussed in detail;and the possible strategies for these issues are proposed.We expect this review can provide a roadmap towards better technologies for recycling LIBs,shed light on the future development of novel battery recycling technologies to promote the environmental benignity and economic viability of the battery industry and pave way for the large-scale application of LIBs in industrial fields in the near future.

Fuel Spray Dynamic Characteristics of GDI High Pressure Injection System

In order to improve the fuel consumption and exhaust emission for gasoline engines,gasoline direct injection（GDI） system is spotlighted to solve these requirements.Thus,many researchers focus on the investigation of spray characteristics and the fuel formation of GDI injector.This paper presents a complete numerical and experimental characterization of transient gasoline spray from a high pressure injection system equipped with a modern single-hole electric controlled injector in a pressurized constant volume vessel.The numerical analysis is carried out in a one-dimensional model of fuel injection system which is developed in the AVL HYDSIM environment.The experimental analyses are implemented through a self-developed injection rate measurement device and spray evolution visualization system.The experimental results of injection rate and spray dynamics are taken to tune and validate the built model.The visualization system synchronize a high speed CMOS camera to obtain the spray structure,moreover,the captured images are taken to validate the injector needle lift process which is simulated in the model.The reliability of the built model is demonstrated by comparing the numerical results with the experimental data.The formed vortex structure at 0.8 ms is effectively disintegrated at 6.2 ms and the spray dynamics become rather chaotic.The fuel flow characteristics within injector nozzle extremely influence the subsequent spray evolution,and therefore this point should be reconsidered when building hybrid breakup GDI spray model.The spray tip speed reach the maximum at 1.18 ms regardless of the operation conditions and this is only determined by the injector itself.Furthermore,an empirical equation for the spray tip penetration is obtained and good agreement with the measured results is reached at a certain extent.This paper provides a methodology for the investigation of spray behavior and fuel distribution of GDI engine design.

Experimental Analysis of the Influence of Exhaust Thermal Management on Engine NO_(x) Emission

Exhaust thermal management is essential to allow engines to meet the Euro VI emissions standards and reducing nitrogen oxide emissions is one of the most important targets being pursued nowadays.Along these lines,in the present study,engine’s thermal performances have been evaluated on the basis of a WHTC test,namely a transient engine dynamometer schedule defined by the global technical regulation(GTR)developed by the UN ECE GRPE group(the GTR is covering a world-wide harmonized heavy-duty certification(WHDC)procedure for engine exhaust emissions).The influence of thermal management on fuel consumption,intake,and tailpipe NO_(x) have been quantitatively analyzed for the overrun state.The results have shown that there can be a strong influence on the after-treatment temperatures and tailpipe NO_(x).In particular,the average temperature upstream of the diesel oxidation catalyst(DOC)has been found to increase from 245°C to 254°C,the average temperature of the selective catalytic reduction(SCR)to increase from 248°C to 253°C,the SCR’s minimum temperature to increase from 196°C to 204°C,and the peak value of the NO_(x) emissions in the low-temperature region to decrease from 73 to 51 mg/s.However,the influence of the overrun state’s thermal management strategy on the fuel consumption,the air intake,the ammonia storage,the NO_(2)/NO_(x) ratio,and the urea consumption has been observed to be relatively limited.

Selective catalytic reduction of NO_(x) with NH_(3) assisted by non-thermal plasma over CeMnZrO_(x)@TiO_(2) core–shell catalyst

The presented work reports the selective catalytic reduction(SCR)of NO_(x) assisted by dielectric barrier discharge plasma via simulating marine diesel engine exhaust,and the experimental results demonstrate that the low-temperature activity of NH_(3)-SCR assisted by non-thermal plasma is enhanced significantly,particularly in the presence of a C_(3)H_(6) additive.Simultaneously,CeMnZrO_(x)@TiO_(2) exhibits strong tolerance to SO_(2) poisoning and superior catalytic stability.It is worthwhile to explore a new approach to remove NO_(x) from marine diesel engine exhaust,which is of vital significance for both academic research and practical applications.

NOx storage and reduction assisted by non-thermal plasma over Co/Pt/Ba/γ-Al2O3 catalyst using CH_(4) as reductant

NOx storage and reduction(NSR)technology has been regarded as one of the most promising strategies for the removal of nitric oxides(NOx)from lean-burn engines,and the potential of the plasma catalysis method for NOx reduction has been confirmed in the past few decades.This work reports the NSR of nitric oxide(NO)by combining non-thermal plasma(NTP)and Co/Pt/Ba/γ-Al2O3(Co/PBA)catalyst using methane as a reductant.The experimental results reveal that the NOx conversion of NSR assisted by NTP is notably enhanced compared to the catalytic efficiency obtained from NSR in the range of 150°C–350°C,and NOx conversion of the 8%Co/PBA catalyst reaches 96.8%at 350°C.Oxygen(O_(2))has a significant effect on the removal of NOx,and the NOx conversion increases firstly and then decreases when the O_(2)concentration ranges from 2%to 10%.Water vapor reduces the NOx storage capacity of Co/PBA catalysts on account of the competition for adsorption sites on the surface of Co/PBA catalysts.There is a negative correlation between sulfur dioxide(SO_(2))and NOx conversion in the NTP system,and the 8%Co/PBA catalyst exhibits higher NOx conversion compared to other catalysts,which shows that Co has a certain SO_(2)resistance.

Left-turn-acr oss-path-fr om-opposite-direction accidents in China:CIDAS accident study

Left-turn-across-path-from-opposite-direction(LTAP/OD)conflicts are one of the most common crash types at intersections.The research aims to reveal the general and dynamic information about the conflict for the most relevant street layouts for each conflict configuration of the LTAP/OD accidents involving passenger cars,motorcycles and Ebikes.The analysis was based on 276 LTAP/OD 157 car-to-motorcycle conflicts and 75 car-to-Ebike conflicts.Most accidents belonging to the three types were observed at the wo accidents collected by the China in-depth accident study(CIDAS 2011-2019).The LTAP/OD accidents include 44 car-to-car conflicts.street layout without a green belt separating the oncoming lane and no offset lane between the turning car and the oncoming traffic,the main distance between both vehicles in the beginning of the critical situation being about four metres,occurring in the clear day with no rain and at junctions lighted either because of daylight or based on street lighting.In terms of the turning car initial speed,the range is 15-30 km/h for most car-to-car and car-to-motorcycle accidents,but 30-40 km/h for most car-to-Ebike accidents.As for the collision speed,this range is between10 km/h and 20km/h for car-to-car and car-to-Ebike accidents and between10 km/h and passenger cars,the maximum longitudinal distance is 60 m for both types of accidents and the maximum lateral distance ranges 25 km/h for car-to-motorcycle crashes.Based on the distributions of objective motorcycles’and Ebikes'positions in collisions with from -20 m to 20m and from -15 m to 15 m,respectively.

Efficient NO_x abatement by passive adsorption over a Pd-SAPO-34 catalyst prepared by solid-state ion exchange

Palladium-exchanged chabazite(Pd-CHA) zeolites as passive NO_x adsorbers(PNAs) enable efficient purification of nitrogen oxides(NO_x) in cold-start diesel exhausts. Their commercial application, however,is limited by the lack of facile preparation method. Here, high-performance CHA-type Pd-SAPO-34 zeolite was synthesized by a modified solid-state ion exchange(SSIE) method using PdO as Pd precursor,and demonstrated superior PNA performance as compared to Pd-SAPO-34 prepared by conventional wetchemistry strategies. Structural characterization using Raman spectroscopy and X-ray diffraction revealed that the SSIE method avoided water-induced damage to the zeolite framework during Pd loading. Mechanistic investigations on the SSIE process by in situ infrared spectroscopy and X-ray photoelectron spectroscopy disclosed that, while PdO precursor was mainly converted to Pd^(2+) cations coordinated to the zeolite framework by consuming the-OH groups of the zeolite, a portion of PdO could also undergo thermal decomposition to form highly dispersed Pd~0 clusters in the pore channels. This simplified and scalable SSIE method paves a new way for the cost-effective synthesis of defect-free high-performance Pd-SAPO-34 zeolites as PNA catalysts.

Scenario analysis of hydrofluorocarbons emission reduction in China's mobile air-conditioning sector

With the Kigali Amendment(KA)coming into effect in China,the control of hydrofuorocarbons(HFCs)emissions has become more imperative.The mobile air-conditioning(MAC)sector is one of the important HFCs consumer sectors,and therefore studying its feasible mitigation paths and costs is of great significance to Chinas successful implementation of KA.This study used the bottom-up method with updated emission factors to re-evaluate the emission inventory of HFCs from the MAC sector in China from 2005 to 2020.The average annual growth rate of HFCs consumption in the MAC sector is 9.8%,and HFCs emissions have increased from 5.8(5.3-6.2)kt in 2005 to 22.2(20.6-23.8)kt in 2020,with an average annual growth rate of 8.8%.Using the Gompertz model combined with the Weibull function of vehicle survival rate,the ownership and new registrations of internal combustion engine vehicles(ICEVs)and electric vehicles(EVs)in China are predicted.The ownership of ICEVs and EVs is projected to be 310 million and 91 million in 2030,respectively and 2 million and 641 million in 2060,respectively.HFCs emissions in the MAC sector would reach 59.8(55.3-64.3)kt(80.093.0 Mt CO_(2-eq))in 2060 if without any control measure.To implement the KA,the cumulative of 1.6 Gt CO_(2-eq) emissions would be reduced.Under the other two accelerated mitigation scenarios,the MAC sector's HFCs will reach their emissions peak in 2028 and 2025 and achieve zero emissions in 2050 and 2046,respectively.Under the accelerated mitigation with recovery scenario,the cumulative emissions are only 15.0%of the business as usual(BAU)scenario.Using HFO-1234yf as the substitute,the unit abatement cost of the MAC sector is 27.3-37.4 USD _(t)^(-1)CO_(2-eq).

Weakening CO poisoning over size-and support-dependent Pt_(n)/X-graphene catalyst(X=C,B,N,n=1-6,13)

CO poisoning is one of the obstacles for platinum catalysts toward the electro-catalysis process for proton exchange membrane fuel cell(PEMFC)or direct methanol fuel cell(DMFC).Herein,we aim to weaken the CO poisoning on Pt by varying the cluster sizes and supports via doping graphene with B and N based on DFT+D3 calculations.

Effect of cobalt doping on ceria-zirconia mixed oxide: Structural characteristics, oxygen storage/release capacity and three-way catalytic performance

The effect of Co doping on ceria-zirconia mixed oxides was investigated for Co0.1Ce0.6Zr0.3Ox sample prepared by sol-gel method. The Pd-only three-way catalyst （TWC） was obtained by incipient wetness impregnation with 0.5 wt.% Pd loading. The structural and oxygen handling properties were analyzed by X-ray diffraction （XRD）, H2-temperature programmed reduction （H2-TPR） and the dynamic oxygen storage capacity （DOSC）. The introduction of Co into ceria-zirconia lattice strongly modified the mobility of oxygen and enhanced the DOSC performance. Pd-only TWC based on the Co0.1Ce0.6Zr0.3Ox support exhibited superior activity for water-gas shift and steam reforming and ampli- fied amplitude of stoichiometric window.

Steam effects over Pd/Ce_(0.67)Zr_(0.33)O_2 three-way catalyst

In the purification process of automobile exhaust,existing water plays an important role as an oxidant,which converts CO and hydrocarbons（HCs） by the water-gas shift（WGS） and the steam reforming（SR） reactions,respectively,especially at high temperatures.Meanwhile it is major component of the exhaust which can affect significantly the thermal stability of the three-way catalyst.Activity experiments were carried out close to the real operation conditions（GHSV,concentration,etc.） with a Pd/Ce0.67Zr0.33O2 catalyst supplying information on the CO and C3H8 oxidation reactions in feedstream formed by different reactant combinations.The obtained results showed that the activity of the CO and C3H8 oxidation was promoted by the addition of steam due to the WGS and SR reactions.The WGS and SR reaction were competitive under oxygen-lean conditions.The kinetic analysis was considered for WGS and SR reactions.

Steam effects over Pd/Ce_(0.67)Zr_(0.33)O_2-Al_2O_3 three-way catalyst

Ceria-zirconia-alumina （CZA） solid solution was prepared by sol-gel method in the present study. 0.5 wt.% Pd supported on CZA was prepared by incipient wetness impregnation. The steam effects for CO and C3H8 oxidation, three-way catalytic activity and stoichiometric window property were studied. The light-off temperature of the CO oxidation reaction shifted to a lower temperature due to the water-gas shift （WGS） reactions. The oxidation of C3H8 was enhanced due to the steam reforming （SR） reactions. The steam promoted the C3H8 oxidation and NO reduction in three-way catalytic reaction. The amplitude of stoichiometric window was amplified by the addition of water to the feed stream.

Modulate the superficial structure of La_(2)Ce_(2)O_(7) catalyst with anchoring CuO_(x) species for the selective catalytic oxidation of NH_(3)

Air contamination caused by the ammonia slip phenomenon has gradually captured the researcher’s extensive attention.An effective strategy for controlling fugitive NH_(2)is critical to improving the air quality and living environment.In the present work,CuO_(x)/La_(2)Ce_(2)O_(7)composite as a potential candidate catalyst is synthesized through the electrostatic adsorption method for the selective catalytic oxidation(SCO_(2))of NH_(2)to N.The 5%Cu Ox/La_(2)Ce_(2)O_(7)exhibits the best catalytic activity(T=243℃)and ammonia conversion efficiency.The improvement of performance is mainly attributed to the superficial connection of[Ce-O-Cu],which enhances the capturing ability of ammonia molecule and accelerates the dissociating efficiency of N–H bonding for Nevolution,simultaneously.This work provides a facile method to synthesis pyrochlore-like composite catalyst of NH_(2)-SCO_(2) for solving the problem of ammonia slip pollution in the future.

Optimized Pt-MnO_(x) interface in Pt-MnO_(x)/3DOM-Al_(2)O_(3)catalysts for enhancing catalytic soot combustion

The catalysts of three-dimensionally ordered macroporous(3 DOM)Al_(2)O_(3)-supported core-shell structured Pt@MnOx nanoparticles(3 DOM-Pt@MnO_(x)/Al_(2)O_(3))were successfully prepared by the gas bubbling-assisted membrane reduction-precipitation(GBMR/P)method.Pt@MnO_(x)core-shell nanoparticles(NPs)are highly dispersed on the inner surface of 3 DOM-Al_(2)O_(3)support.Pt@MnOx/3 DOM-Al_(2)O_(3)catalysts,which combine both advantages of high-efficiency soot-catalyst contact by 3 DOM-Al_(2)O_(3)structure and the abundant active sites by the optimized Pt-MnO_(x)interface,exhibit high catalytic activities for soot combustion,and the catalytic activities are strongly dependent on the thickness of MnO_(x)shell.Among the catalysts,3 DOM-Pt@MnO_(x)/Al_(2)O_(3)-1 catalyst with optimized Pt-MnO_(x)interface shows the highest catalytic activity for soot combustion,i.e.,its values of T_(50)and S_(CO_(2))^(m) are 351℃and98.6%,respectively.The highest density of Pt-MnO_(x)active sites for adsorptio n-activation of gaseous O_(2)is responsible for enhancing catalytic activity for soot combustion.Pt@MnOx/3 DOM-Al_(2)O_(3)catalysts are promising to practical applications for the emission reduction of soot particles.

Investigation on the urea deposit formation and thermal decomposition characteristics in the SCR aftertreatment system of a diesel engine

Selective catalytic reduction is the most efficient and reliable equipment for NOx control in current diesel engines. However, the issue of urea crystallization becomes increasingly serious with the implement of the new emissions standards. In this paper, urea deposit samples collected from engine test bed and tube furnace were characterized by thermogravimetric analysis and Fourier transform-infrared analysis to aid the comprehension of urea deposit formation. Moreover, thermogravimetric tests were conducted to disclose the effects of catalyst on the thermal decomposition processes of urea deposit. The results indicated that less temperature resistant species are formed in the engine test bed than in the tube furnace at conditions with the same temperatures. The main compositions in the World Harmonized Transient Cycle(WHTC) urea deposits are urea, cyanuric acid(CYA) and ammelide, implying that accelerating the decomposition of these species could prevent the accumulation of urea deposit. CuWTi, Cu β and CuZSM catalysts could lead to increased yield of CYA during pure urea thermolysis. Cu β, CuWTi and VWTi catalysts tend to promote the thermolysis of CYA while VWTi has the most significant catalytic effects on the thermal decomposition of ammelide and ammeline.

Facile synthesis of defected TiO_(2-x)(B) nanosheet/graphene oxide hybrids with high photocatalytic H_(2) activity

TiO_(2)(B) nanosheets/GO(graphene oxide) hybrids are considered to be outstanding performance photocatalysts for high efficiency of H_(2) evolution. However, they still suffer severe challenges during the synthetic processes, such as a large amount of the capping agents adhering on the surface and easy occurrence of aggregation. To figure out these obstacles, Ar plasma treatment as a modified method in this study not only enable the TiO_(2)(B) nanosheets distributed uniformly on the GO sheets but also engineer defects within TiO_(2)(B) nanosheets to significantly improve the photocatalytic activity for the water splitting. The hydrogen evolution rate of the TiO_(2)-x(B)/GO sheets is 1.4 times higher compared with that of original TiO_(2)(B)/GO sheets without Ar plasma treatment. The improved photocatalytic properties were owing to the synergetic effects of oxygen vacancies and the heterojunction between GO and TiO_(2)(B), which can promote the visible light utilization and accelerate separation and transportation of photogenerated electron-holes. This study can provide a facile pathway to prepare the two-dimensional hybrid photocatalysts with high photocatalytic H_(2) activity.

Modeling and Decentralized Predictive Control of Ejector Circulation‑Based PEM Fuel Cell Anode System for Vehicular Application

The dynamic response of fuel cell vehicle is greatly affected by the pressure of reactants.Besides,the pressure difference between anode and cathode will also cause mechanical damage to proton exchange membrane.For maintaining the relative stability of anode pressure,this study proposes a decentralized model predictive controller(DMPC)to control the anodic supply system composed of a feeding and returning ejector assembly.Considering the important influence of load current on the system,the piecewise linearization approach and state space with current-induced disturbance compensation are com-paratively analyzed.Then,an innovative switching strategy is proposed to prevent frequent switching of the sub-model-based controllers and to ensure the most appropriate predictive model is applied.Finally,simulation results demonstrate the better stability and robustness of the proposed control schemes compared with the traditional proportion integration differentia-tion controller under the step load current,variable target and purge disturbance conditions.In particular,in the case of the DC bus load current of a fuel cell hybrid vehicle,the DMPC controller with current-induced disturbance compensation has better stability and target tracking performance with an average error of 0.15 kPa and root mean square error of 1.07 kPa.