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1.
Developing low-temperature SO2-tolerant catalysts for the selective catalytic reduction of NOx is still a challenging task. The sulfation of active metal oxides and deposition of ammonium bisulfate deactivate catalysts, due to the difficult decomposition of the as-formed sulfate species at low temperatures(<300 °C). In recent years, metal sulfate catalysts have attracted increasing attention owing to their good catalytic activity and strong SO2 tolerance at hi...  相似文献   

2.
A series of CeO_2–ZrO_2–WO_3(CZW)catalysts prepared by a hydrothermal synthesis method showed excellent catalytic activity for selective catalytic reduction(SCR)of NO with NH_3 over a wide temperature of 150–550°C.The effect of hydrothermal treatment of CZW catalysts on SCR activity was investigated in the presence of 10% H_2O.The fresh catalyst showed above 90% NO_x conversion at 201–459°C,which is applicable to diesel exhaust NO_x purification(200–440°C).The SCR activity results indicated that hydrothermal aging decreased the SCR activity of CZW at low temperatures(below 300°C),while the activity was notably enhanced at high temperature(above 450°C).The aged CZW catalyst(hydrothermal aging at 700°C for 8 hr)showed almost 80% NO_x conversion at 229–550°C,while the V_2O_5–WO_3/TiO_2 catalyst presented above 80% NO_x conversion at 308–370°C.The effect of structural changes,acidity,and redox properties of CZW on the SCR activity was investigated.The results indicated that the excellent hydrothermal stability of CZW was mainly due to the CeO_2–ZrO_2 solid solution,amorphous WO_3 phase and optimal acidity.In addition,the formation of WO_3 clusters increased in size as the hydrothermal aging temperature increased,resulting in the collapse of structure,which could further affect the acidity and redox properties.  相似文献   

3.
Herein,a one-step co-pyrolysis protocol was adopted for the first time to prepare a novel pyrogenic carbon-Cu0/Fe3O4 heteroatoms (FCBC) in CO2 ambiance to discern the roles of each component in PDS activation.During co-pyrolysis,CO2 catalyzed formation of reducing gases by biomass which facilitated reductive transformation of Fe3+ and Cu2+ to Cu0 and Fe3O4,respectively.According to the a...  相似文献   

4.
Examining the contribution of fossil fuel CO2to the total CO2changes in the atmosphere is of primary concern due to its alarming levels of fossil fuel emissions over the globe,specifi cally developing countries.Atmospheric radiocarbon represents an important observationa constraint and utilized to trace fossil fuel derived CO2(CO2ff) in the atmosphere.For the firs time,we have presented a detailed analysis on the spatial distribution of fossil fuel der...  相似文献   

5.
Integrated CO2capture and utilization (ICCU) technology requires dual functional materials(DFMs) to carry out the process in a single reaction system.The influence of the calcination atmosphere on efficiency of 4%Ru-8%Na2CO3-8%CaO/γ-Al2O3DFM is studied.The adsorbent precursors are first co-impregnated onto alumina and calcined in air.Then,Ru precursor is impregnated and four aliquotes are subjected to different calcination protocols:static a...  相似文献   

6.
CO2 hydrogenation to methanol has become one of the most promising ways for CO2 utilization,however,the CO2 conversion rate and methanol selectivity of this reaction still need to be improved for industrial application.Here we investigated the structure-activity relationship for CO2 conversion to methanol of In2O3-based catalysts by modulating morphology and decorating Au.Three different Au/In2O3catalysts wer...  相似文献   

7.
The rapid deactivation of cost-effective MnO2-based catalysts in humid air limits their application in practice,and the identification of the role of water in an oxidation process is significant for developing water-resistant MnO2-based catalysts.Here,CuMnO2showed a20.3%HCHO conversion in 10 hr at room temperature in humid air with relative humidity of 40%,but deactivated in 3 hr in dry air.The excellent activity and stability of HCHO oxidation in humid air were ...  相似文献   

8.
We first present preparation of MnOx–CeO_2–Al_2O_3 catalysts with varying Mn contents through a self-propagating high-temperature synthesis(SHS) method, and studied the application of these catalysts to the selective catalytic reduction of NOxwith NH3(NH_3-SCR).Using the catalyst with 18 wt.% Mn(18 MnCe1Al2), 100% NO conversion was achieved at 200°C and a gas hourly space velocity of 15384 hr-1, and the high-efficiency SCR temperature window, where NO conversion is greater than 90%, was widened to a temperature range of 150–300°C. 18 MnCe1Al2 showed great resistance to SO_2(100 ppm)and H_2O(5%) at 200°C. The catalysts were characterized using X-ray diffraction, X-ray photoelectron spectroscopy, Brunauer–Emmett–Teller(BET) analysis, scanning electron microscopy, Fourier transform infrared spectroscopy, and H_2 temperature programmed reduction. The characterization results showed that the surface atomic concentration of Mn increased with increasing Mn content, which led to synergism between Mn and Ce and improved the activity in the SCR reaction. 18 MnCe1Al2 has an extensive pore structure,with a BET surface area of approximately 135.4 m~2/g, a pore volume of approximately 0.16 cm~3/g, and an average pore diameter of approximately 4.6 nm. The SCR reaction on 18 MnCe1Al2 mainly followed the Eley-Rideal mechanism. The performances of the MnOx–CeO_2–Al_2O_3 catalysts were good, and because of the simplicity of the preparation process,the SHS method is applicable to their industrial-scale manufacture.  相似文献   

9.
Compressed natural gas(CNG)is most appropriate an alternative of conventional fuel for automobiles.However,emissions of carbon-monoxide and methane from such vehicles adversely affect human health and environment.Consequently,to abate emissions from CNG vehicles,development of highly efficient and inexpensive catalysts is necessary.Thus,the present work attempts to scan the effects of precipitants(Na_2CO_3,KOH and urea)for nickel cobaltite(Ni Co_2O_4)catalysts prepared by co-precipitation from nitrate solutions and calcined in a lean CO-air mixture at 400°C.The catalysts were used for oxidation of a mixture of CO and CH_4(1:1).The catalysts were characterized by X-ray diffractometer,Brunauer–Emmett–Teller surface-area,X-ray photoelectron spectroscopy;temperature programmedreductionandScanningelectronmicroscopycoupledwith Energy-Dispersive X-Ray Spectroscopy.The Na_2CO_3was adjudged as the best precipitant for production of catalyst,which completely oxidized CO-CH_4mixture at the lowest temperature(T_(100)=350°C).Whereas,for catalyst prepared using urea,T_(100)=362°C.On the other hand the conversion of CO-CH_4mixture over the catalyst synthesized by KOH limited to 97%even beyond 400°C.Further,the effect of higher calcination temperatures of 500 and600°C was examined for the best catalyst.The total oxidation of the mixture was attained at higher temperatures of 375 and 410°C over catalysts calcined at 500 and 600°C respectively.Thus,the best precipitant established was Na_2CO_3and the optimum calcination temperature of 400°C was found to synthesize the Ni Co_2O_4catalyst for the best performance in CO-CH_4oxidation.  相似文献   

10.
Pt catalysts with nitrogen-doped graphene oxide (GO) as support and CeO2 as promoter were prepared by impregnation method,and their catalytic oxidation of formaldehyde (HCHO) at room temperature was tested.The Pt-CeO2/N-rGO (reduced GO) with a mass fraction of 0.7% Pt and 0.8%CeO2 exhibited an excellent catalytic performance with the 100% conversion of HCHO at room temperature.Physicochemical characterization demonstrated that nitrogendoping greatly increased the...  相似文献   

11.
In the quest for the development of thermally stable, highly active and low-cost catalysts for use in catalyzed diesel particulate filter, nano-composites are new areas of research. Therefore, we reported the easy synthesis of spinel NiCo2O4/perovskite LaCoO3 nano-composite,and its individual oxides NiCo2O4and LaCoO3 for comparison. The detailed insights into the physio-chemical characteristics of formed NiCo2O4  相似文献   

12.
Solar-driven carbon dioxide (CO2) conversion including photocatalytic (PC),photoelectrochemical (PEC),photovoltaic plus electrochemical (PV/EC) systems,offers a renewable and scalable way to produce fuels and high-value chemicals for environment and energy sustainability.This review summarizes the basic fundament and the recent advances in the field of solar-driven CO2 conversion.Expanding the visible-light absorption is an important strategy to improve solar energy convers...  相似文献   

13.
The PdPtVOx/CeO2-ZrO2(PdPtVOx/CZO) catalysts were obtained by using different approaches,and their physical and chemical properties were determined by various techniques.Catalytic activities of these materials in the presence of H2O or SO2were evaluated for the oxidation of ethylbenzene (EB).The PdPtVOx/CZO sample exhibited high catalytic activity,good hydrothermal stability,and reversible sulfur dioxide-poisoning perfo...  相似文献   

14.
Vehicular emissions are considered one of the major anthropogenic sources of greenhouse gases and poor air quality in metropolitan cities.This study aims to see the correlation of CO2,CH4,and CO through monitoring over a period from December 2020 to October 2021 covering three seasons’winter,summer,and monsoon at two different traffic locations of Delhi having different traffic volumes,road patterns,and traffic management.The annual average morning concentration of CO2...  相似文献   

15.
Herein, a series of niobium oxide supported cerium nanotubes(Ce NTs) catalysts with different loading amount of Nb2O5(0–10 wt.%) were prepared and used for selective catalytic reduction of NOxwith NH3(NH3-SCR) in the presence of CH2Cl2. Commercial V2O5-WO3-TiO2 catalyst was also prepared for comparison. The physcial properties and chemical properties of the Nb2O5 lo...  相似文献   

16.
In order to develop a catalyst with high activity for catalytic wet oxidation (CWO) process at room temperature and atmospheric pressure, Fe2O3-CeO2-TiO2/γ-Al2O3 catalyst was prepared by consecutive impregnation method and the prepared parameters were optimized. The structure of the catalyst was characterized by BET, XRF, SEM and XPS technologies, and the actual wastewater was used to investigate the catalytic activity of Fe2O3-CeO2-TiO2/γ-Al2O3 in CWO process. The experimental results showed that the prepared catalyst exhibited good catalytic activity when the doping amount of Ti was 1.0 wt% (the weight ratio of Ti to carriers), and the middle product, Fe2O3-CeO2-TiO2/γ-Al2O3, was calcined in 450℃ for 2 h. The CWO experiment for treating actual dye wastewater indicated that the COD, color and TOC of actual wastewater were decreased by 62.23%, 50.12% and 41.26% in 3 h, respectively, and the ratio of BOD5/COD was increased from 0.19 to 0.30.  相似文献   

17.
The heterogeneous loss of HO2 radicals onto ambient aerosols plays an important role in tropospheric chemistry. However, sparse investigation of the dominating parameters controlling the HO2 uptake coefficients onto ambient aerosols(γHO2) has largely hindered the application of the measured γHO2 to the global spatial prediction. Here we induced an offine method using LFP-LIF technique to measure the kinetics of HO2 uptake onto ambient aeroso...  相似文献   

18.
Reducing CO2emissions of the iron and steel industry,a typical heavy CO2-emitting sector is the only way that must be passed to achieve the‘dual-carbon’goal,especially in China.In previous studies,however,it is still unknown what is the difference between blast furnace basic oxygen furnace (BF-BOF),scrap-electric furnace (scrap-EF) and hydrogen metallurgy process.The quantitative research on the key factors affecting CO2emissions is insufficient There is also a l...  相似文献   

19.
Artificial CO2 removal from the atmosphere (also referred to as negative CO2 emissions)has been proposed as a potential means to counteract anthropogenic climate change.Here we use an Earth system model to examine the response of ocean acidification to idealized atmospheric CO2 removal scenarios.In our simulations,atmospheric CO2 is assumed to increase at a rate of 1% per year to four times its pre-industrial value and then decreases to the pre-industr...  相似文献   

20.
The coordinated control of PM2.5 and ozone has become the strategic goal of national air pollution control.Considering the gradual decline in PM2.5concentration and the aggravation of ozone pollution,a better understanding of the coordinated control of PM2.5 and ozone is urgently needed.Here,we collected and sorted air pollutant data for 337 cities from 2015 to 2020 to explore the characteristics of PM2.5 and ozone pollution based on China’s five major...  相似文献   

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