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Bifunctional interstitial phosphorous doping strategy boosts platinum-zinc alloy for efficient ammonia oxidation reaction and hydrogen evolution reaction 被引量:2
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作者 Tianqi Yu Kexin Tan +2 位作者 Jia Wu Yongjin Zou Shibin Yin 《Nano Research》 SCIE EI CSCD 2024年第3期1182-1189,共8页
It is still a lack of bifunctional catalysts for ammonia oxidation reaction(AOR)and hydrogen evolution reaction(HER)due to their different reaction mechanisms.In this work,P is doped into PtZn alloy by calcination wit... It is still a lack of bifunctional catalysts for ammonia oxidation reaction(AOR)and hydrogen evolution reaction(HER)due to their different reaction mechanisms.In this work,P is doped into PtZn alloy by calcination with NaH_(2)PO_(2) as P source to induce the lattice tensile strain of Pt and the electronic interaction between P and Zn,which optimizes the AOR and HER activity simultaneously.The sample with the optimal P content can drive the AOR peak current density of 293.6 mA·mgPt^(-1),which is almost 2.7 times of Pt.For HER,the overpotential at^(-1)0 mA·cm^(-2) is only 23 mV with Tafel slope of 34.1 mV·dec^(-1).Furthermore,only 0.59 V is needed to obtain 50 mA·mgPt^(-1) for ammonia electrolysis under a two-electrode system.Therefore,this work shows an ingenious method to design bifunctional catalysts for ammonia electrolysis. 展开更多
关键词 PtZn alloy phosphorous doping ammonia oxidation reaction hydrogen evolution reaction bifunctional catalyst
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Molecular catalysts for electrocatalytic ammonia oxidation
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作者 Jun Li Feiyang Zhang +2 位作者 Huatian Xiong Yuanyuan Cai Biaobiao Zhang 《Science China Chemistry》 SCIE EI CAS CSCD 2024年第12期3976-3993,共18页
Electrocatalytic ammonia oxidation reaction(eAOR)is of significance to ammonia fuel economy and the production of valuable N-containing products,such as nitrite,nitrate and hydrazine.The study of well-defined molecula... Electrocatalytic ammonia oxidation reaction(eAOR)is of significance to ammonia fuel economy and the production of valuable N-containing products,such as nitrite,nitrate and hydrazine.The study of well-defined molecular catalysts offers rich insights in terms of the detailed mechanism of ammonia oxidation.This review analyzes the thermodynamics of ammonia oxidation reactions and summarizes the current progress in molecular electrocatalysts in this booming field.We emphasized the factors that influence the selectivity of products and further discussed the challenges in designing efficient catalysts. 展开更多
关键词 ELECTROCATALYTIC ammonia oxidation reaction HYDRAZINE NITRATE molecular catalyst
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Response of soil microbial activities and ammonia oxidation potential to environmental factors in a typical antimony mining area 被引量:1
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作者 Aihua Wang Shujun Liu +4 位作者 Jun Xie Wei Ouyang Mengchang He Chunye Lin Xitao Liu 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2023年第5期767-779,共13页
Mining,smelting and tailing deposition activities can cause metal(loid)contamination in surrounding soils,threatening ecosystems and human health.Microbial indicators are sensitive to environmental factors and have a ... Mining,smelting and tailing deposition activities can cause metal(loid)contamination in surrounding soils,threatening ecosystems and human health.Microbial indicators are sensitive to environmental factors and have a crucial role in soil ecological risk assessment.Xikuangshan,the largest active antimony(Sb)mine in the world,was taken as the research area.The soil properties,metal(loid)contents and microbial characteristics were investigated and their internal response relationships were explored by multivariate statistical analysis.The assessment of the single pollution index and Nemerow synthetic pollution index(PN)showed that the soils were mainly polluted by Sb,followed by Cd and As,in which sampling site S1 had a slight metal(loid)pollution and the other sampling sites suffered from severe synthetic metal(loid)pollution.The microbial characteristics were dissimilar among sampling points at different locations from the mining area according to hierarchical cluster analysis.The correlation analysis indicated that fluorescein diacetate hydrolase,acid phosphatase,soil basal respiration andmicrobial biomass carbonwere negatively correlatedwith PN,indicating their sensitivity to combined metal(loid)contamination;that dehydrogenase was positively correlated with pH;and that urease,potential ammonia oxidation and abundance of ammonia-oxidizing bacteria and archaea were correlated with N(nitrogen)contents.However,β-glucosidase activity had no significant correlations with physicochemical properties and metal(loid)contents.Principal components analysis suggested bioavailable Sb and pH were the dominant factors of soil environment in Xikuangshan Sb mining area.Our results can provide a theoretical basis for ecological risk assessment of contaminated soil. 展开更多
关键词 Antimony mining area Metal(loid)pollution Microbial characteristics Enzyme activities ammonia oxidation potential
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Responses of potential ammonia oxidation and ammonia oxidizers community to arsenic stress in seven types of soil
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作者 Yanan Wang Xibai Zeng +3 位作者 Yang Zhang Nan Zhang Liyang Xu Cuixia Wu 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2023年第5期15-29,共15页
Soil arsenic contamination is of great concern because of its toxicity to human,crops,and soil microorganisms.However,the impacts of arsenic on soil ammonia oxidizers communities remain unclear.Seven types of soil spi... Soil arsenic contamination is of great concern because of its toxicity to human,crops,and soil microorganisms.However,the impacts of arsenic on soil ammonia oxidizers communities remain unclear.Seven types of soil spiked with 0 or 100 mg arsenic per kg soil were incubated for 180 days and sampled at days 1,15,30,90 and 180.The changes in the community composition and abundance of ammonia oxidizing bacteria(AOB)and ammonia oxidizing archaea(AOA)were analyzed by terminal restriction fragment length polymorphism(TRFLP)analysis,clone library sequencing,and quantitative PCR(qPCR)targeting amoA gene.Results revealed considerable variations in the potential ammonia oxidation(PAO)rates in different soils,but soil PAO was not consistently significantly inhibited by arsenic,probably due to the low bioavailable arsenic contents or the existence of functional redundancy between AOB and AOA.The variations in AOB and AOA communities were closely associated with the changes in arsenic fractionations.The amoA gene abundances of AOA increased after arsenic addition,whereas AOB decreased,which corroborated the notion that AOA and AOB might occupy different niches in arsenic-contaminated soils.Phylogenetic analysis of amoA gene-encoded proteins revealed that all AOB clone sequences belonged to the genus Nitrosospira,among which those belonging to Nitrosospira cluster 3a were dominant.The main AOA sequence detected belonged to Thaumarchaeal Group 1.1b,which was considered to have a high ability to adapt to environmental changes.Our results provide new insights into the impacts of arsenic on the soil nitrogen cycling. 展开更多
关键词 ammonia oxidizers Arsenic Potential ammonia oxidation(PAO) rate Ecological niche Terminal restriction fragment length polymorphism(T-RFLP) analysis
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Solar hydrogen production from electrochemical ammonia splitting powered by a single perovskite solar cell
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作者 Anna MBeiler Wenhui Li +2 位作者 Alisa Denisiuk Emilio Palomares Antoni Llobet 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第5期292-295,共4页
For carbon-free electrochemical fuel formation,the electrochemical cell must be powered by renewable energy.Obtaining solar-powered H_(2) fuel from water typically requires multiple photovoltaic cells and/or junctions... For carbon-free electrochemical fuel formation,the electrochemical cell must be powered by renewable energy.Obtaining solar-powered H_(2) fuel from water typically requires multiple photovoltaic cells and/or junctions to drive the water splitting reaction.Because of the lower thermodynamic requirements to oxidize ammonia compared to water,solar cells with smaller open circuit voltages can provide the required potential for ammonia splitting.In this work,a single perovskite solar cell with an open-circuit potential of 1.08 V is coupled to a 2-electrode electrochemical cell employing hybrid electroanodes functionalized with Ru-based molecular catalysts.The device is active for more than 30 min,producing N_(2) and H_(2) in a 1:2.9 ratio with 89%faradaic efficiency with no external applied bias.This work illustrates that hydrogen production from ammonia can be driven by conventional semiconductors. 展开更多
关键词 ammonia oxidation Redox catalysis Perovskites Solarfuels Transitionmetal complexes
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100 W-class green hydrogen production from ammonia at a dual-layer electrode containing a Pt-Ir catalyst for an alkaline electrolytic process
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作者 Donghyun Yoon Sunki Chung +2 位作者 Minjun Choi Eunhyeok Yang Jaeyoung Lee 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第6期352-360,I0009,共10页
Ammonia allows storage and transport of hydrogen over long distances and is an attractive potential hydrogen carrier.Electrochemical decomposition has recently been used for the conversion of ammonia to hydrogen and i... Ammonia allows storage and transport of hydrogen over long distances and is an attractive potential hydrogen carrier.Electrochemical decomposition has recently been used for the conversion of ammonia to hydrogen and is regarded as a future technology for production of CO_(2)-free pure hydrogen.Herein,a heterostructural Pt-Ir dual-layer electrode is developed and shown to achieve successful long-term operation in an ammonia electrolyzer with an anion exchange membrane(AEM).This electrolyzer consisted of eight membra ne electrode assemblies(MEAs)with a total geometric area of 200 cm~2 on the anode side,which resulted in a hydrogen production rate of 25 L h~(-1).We observed the degradation in MEA performance attributed to changes in the anode catalyst layer during hydrogen production via ammonia electrolysis.Furthermore,we demonstrated the relationship between the ammonia oxidation reaction(AOR)and the oxygen evolution reaction(OER). 展开更多
关键词 ammonia oxidation Dual-layer catalyst Green hydrogen Electrolytic process Oxygen evolution reaction
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Fabrication of highly dispersed carbon doped Cu-based oxides as superior selective catalytic oxidation of ammonia catalysts via employing citric acid-modified carbon nanotubes doping CuAl-LDHs
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作者 Fengrong Li Xuezhen Liu +3 位作者 ZhengYi Zhao Xia An Yali Du Xu Wu 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2023年第11期185-196,共12页
In this work,the CuAl-LDO/c-CNTs catalyst was fabricated via in situ oriented assembly of layered-double hydroxides(LDHs)and citric acid-modified carbon nanotubes(c-CNTs)followed by annealing treatment,and evaluated i... In this work,the CuAl-LDO/c-CNTs catalyst was fabricated via in situ oriented assembly of layered-double hydroxides(LDHs)and citric acid-modified carbon nanotubes(c-CNTs)followed by annealing treatment,and evaluated in the selective catalytic oxidation(SCO)of NH_(3)to N_(2).The CuAl-LDO/c-CNTs catalyst presented better catalytic performance(98%NH_(3)conversion with nearly 90%N_(2)selectivity at 513 K)than other catalysts,such as CuAlO_(x)/CNTs,CuAlO_(x)/c-CNTs and CuAl-LDO/CNTs.Multiple characterizations were utilized to analyze the difference of physicochemical properties among four catalysts.XRD,TEM and XPS analyses manifested that CuO and Cu_(2)O nanoparticles dispersed well on the surface of the Cu Al-LDO/c-CNTs catalyst.Compared with other catalysts,larger specific surface area and better dispersion of CuAl-LDO/c-CNTs catalyst were conducive to the exposure of more active sites,thus improving the redox capacity of the active site and NH_(3)adsorption capacity.In-situ DRIFTS results revealed that the internal selective catalytic reduction(iSCR)mechanism was found over CuAl-LDO/c-CNTs catalyst. 展开更多
关键词 Selective catalytic oxidation of ammonia Layered-double hydroxides Cu-based oxides CNTS Citric acid-modified
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Investigation of cubic Pt alloys for ammonia oxidation reaction 被引量:13
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作者 Yat Tung Chan Kumar Siddharth Minhua Shao 《Nano Research》 SCIE EI CAS CSCD 2020年第7期1920-1927,共8页
As a promising fuel candidate,ammonia has been successtully used as anode feed in alkaline fuel cells.However,current technology in catalysts for ammonia electro-oxidation reaction(AOR)with respect to both cost and pe... As a promising fuel candidate,ammonia has been successtully used as anode feed in alkaline fuel cells.However,current technology in catalysts for ammonia electro-oxidation reaction(AOR)with respect to both cost and performance is inadequate to ensure large scale commercial application of direct ammonia fuel cells.Recent studies found that alloying Pt with different transition metals and controlling the morphology of catalysts can improve the AOR activity,and thus potentially can solve the cost issue.Herein,(100)-terminated Pt-M nanocubes(M=3d-transition metals Fe,Co,Ni,Zn)are synthesized via wet-chemistry method and their catalytic activities toward AOR are evaluated.The addition of Fe,Co,Ni and Zn elements can enhance the AOR activity due to decrease in oxophilicity of platinum and bifunctional mechanism.Pt-Zn exhibits the maximum mass activity and specific ativity with values of 0.41 A/mgpt and 169 mA/cm2 that are 1.6 and 1.8 times higher than Pt nanocubes,respectively.Pt-Fe,Pt-Co and PI-Ni nanocubes also ilustrate higher mass and specific activities compared to Pt nanocubes. 展开更多
关键词 ammonia oxidation reaction ELECTROCATALYSTS Pt-3d transition metal nanocubes OH adsorption
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Activating copper oxide for stable electrocatalytic ammonia oxidation reaction via in-situ introducing oxygen vacancies 被引量:3
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作者 Jingjing Huang Zhe Chen +3 位作者 Jinmeng Cai Yongzhen Jin Tao Wang Jianhui Wang 《Nano Research》 SCIE EI CSCD 2022年第7期5987-5994,共8页
Electrocatalytic ammonia oxidation reaction(EAOR)provides an ideal solution for on-board hydrogen supply for fuel cells,while the lack of efficient and durable EAOR catalysts has been a long-standing obstacle for its ... Electrocatalytic ammonia oxidation reaction(EAOR)provides an ideal solution for on-board hydrogen supply for fuel cells,while the lack of efficient and durable EAOR catalysts has been a long-standing obstacle for its practical application.Herein,we reported that the defect engineering via in-situ electrochemically introducing oxygen vacancies(Vo)not only turns the inactive CuO into efficient EAOR catalyst but also achieves a high stability of over 400 h at a high current density of~200 mA·cm^(−2).Theoretical simulation reveals that the presence of Vo on the CuO surface induces a remarkable upshift of the d-band center of active Cu site closer to the Fermi level,which significantly stabilizes the reaction intermediates(*NHx)and efficiently oxidizes NH3 into N2.This Vo-modulated CuO shows a different catalytic mechanism from that on the conventional Pt-based catalysts,paving a new avenue to develop inexpensive,efficient,and robust catalysts,not limited to EAOR. 展开更多
关键词 ELECTROCATALYSIS ammonia oxidation reaction oxygen vacancy CUO stability
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Enhancement on the ammonia oxidation capacity of ammonia-oxidizing archaeon originated from wastewater:Utilizing low-density static magnetic field 被引量:2
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作者 Zeshen Tian Bo Wang +3 位作者 Yuyang Li Bo Shen Fengjuan Li Xianghua Wen 《Frontiers of Environmental Science & Engineering》 SCIE EI CSCD 2021年第5期67-74,共8页
Ammonia-oxidizing archaeon(AOA)could play important roles for nitrogen removal in the bioreactors under conditions such as low pH and low dissolved oxygen.Therefore,enhancing ammonia oxidation capability of AOA has gr... Ammonia-oxidizing archaeon(AOA)could play important roles for nitrogen removal in the bioreactors under conditions such as low pH and low dissolved oxygen.Therefore,enhancing ammonia oxidation capability of AOA has great significance for water and wastewater treatment,especially under conditions like low dissolved oxygen concentration.Utilizing a novel AOA strain SAT1,which was enriched from a wastewater treatment plant by our group,the effect of magnetic field on AOA’s ammonia oxidation capability,its magnetotaxis and heredity were investigated in this study.Compared with control experiment,AOA’s maximum nitrite-N formation rate during the cultivation increased by 56.8%(0.65 mgN/(L·d))with 20 mT magnetic field.Also,it was testified that AOA possessed a certain magnetotaxis.However,results manifested that the enhancement of AOA’s ammonia oxidation capability was not heritable,that is,lost once the magnetic field was removed.Additionally,the possible mechanism of improving AOA’s ammonia oxidation capability by magnetic field was owing to the promotion of AOA single cells’growth and fission,rather than the enhancement of their ammonia oxidation rates.The results shed light on the application of AOA and methods to enhance AOA’s ammonia oxidation capability,especially in wastewater treatment processes under certain conditions. 展开更多
关键词 ammonia-oxidizing archaeon ammonia oxidation Magnetic field Magnetotaxis HEREDITY
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The combined effects of biomass and temperature on maximum specific ammonia oxidation rate in domestic wastewater treatment 被引量:2
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作者 Yukun Zhang Shuying Wang +5 位作者 Shengbo Gu Liang Zhang Yijun Dong Lei Jiang Wei Fan Yongzhen Peng 《Frontiers of Environmental Science & Engineering》 SCIE EI CSCD 2021年第6期341-351,共11页
Measurement and predicted variations of ammonia oxidation rate(AOR)are critical for the optimization of biological nitrogen removal,however,it is difficult to predict accurate AOR based on current models.In this study... Measurement and predicted variations of ammonia oxidation rate(AOR)are critical for the optimization of biological nitrogen removal,however,it is difficult to predict accurate AOR based on current models.In this study,a modified model was developed to predict AOR based on laboratoryscale tests and verified through pilot-scale tests.In biological nitrogen removal reactors,the specific ammonia oxidation rate(SAOR)was affected by both mixed liquor volatile suspended solids(MLVSS)concentration and temperature.When MLVSS increased 1.6,4.2,and 7.1-fold(1.3‒8.9 g/L,at 20℃),the measured SAOR decreased by 21%,49%,and 56%,respectively.Thereby,the estimated SAOR was suggested to modify when MLVSS changed through a power equation fitting.In addition,temperature coefficient(θ)was modified based on MLVSS concentration.These results suggested that the prediction of variations ammonia oxidation rate in real wastewater treatment system could be more accurate when considering the effect of MLVSS variations on SAOR. 展开更多
关键词 Specific ammonia oxidation rate Sequencing batch reactor BIOMASS Temperature coefficient Model simulation
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Monte Carlo Simulation of Kinetics of Ammonia Oxidative Decomposition over the Commercial Propylene Ammoxidation Catalyst (Mo-Bi) 被引量:2
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作者 罗正鸿 詹晓力 +1 位作者 陈丰秋 阳永荣 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2003年第1期110-114,共5页
Monte Carlo method is applied to investigate the kinetics of ammonia oxidative decomposition over the commercial propylene ammoxidation catalyst(Mo-Bi). The simulation is quite in agreement with experimental results. ... Monte Carlo method is applied to investigate the kinetics of ammonia oxidative decomposition over the commercial propylene ammoxidation catalyst(Mo-Bi). The simulation is quite in agreement with experimental results. Monte Carlo simulation proves that the process of ammonia oxidation decomposition is a two-step reaction. 展开更多
关键词 Monte Carlo simulation propylene ammoxidation ammonia oxidative decomposition reaction kinetics
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ROOT EXUDATES FROM CANOLA EXHIBIT BIOLOGICAL NITRIFICATION INHIBITION AND ARE EFFECTIVE IN INHIBITING AMMONIA OXIDATION IN SOIL 被引量:1
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作者 Cathryn A.O'SULLIVAN Elliott G.DUNCAN +3 位作者 Margaret M.ROPER Alan E.RICHARDSON John A.KIRKEGAARD Mark B.PEOPLES 《Frontiers of Agricultural Science and Engineering》 2022年第2期177-186,共10页
A range of plant species produce root exudates that inhibit ammonia-oxidizing microorganisms.This biological nitrification inhibition(BNI)capacity can decrease N loss and increase N uptake from the rhizosphere.This st... A range of plant species produce root exudates that inhibit ammonia-oxidizing microorganisms.This biological nitrification inhibition(BNI)capacity can decrease N loss and increase N uptake from the rhizosphere.This study sought evidence for the existence and magnitude of BNI capacity in canola(Brassica napus).Seedlings of three canola cultivars,Brachiaria humidicola(BNI positive)and wheat(Triticum aestivum)were grown in a hydroponic system.Root exudates were collected and their inhibition of the ammonia oxidizing bacterium,Nitrosospira multiformis,was tested.Subsequent pot experiments were used to test the inhibition of native nitrifying communities in soil.Root exudates from canola significantly reduced nitrification rates of both N.multiformis cultures and native soil microbial communities.The level of nitrification inhibition across the three cultivars was similar to the well-studied high-BNI species B.humidicola.BNI capacity of canola may have implications for the N dynamics in farming systems and the N uptake efficiency of crops in rotational farming systems.By reducing nitrification rates canola crops may decrease N losses,increase plant N uptake and encourage microbial N immobilization and subsequently increase the pool of organic N that is available for mineralization during the following cereal crops. 展开更多
关键词 ammonia oxidizing microorganisms biological nitrification inhibition farming rotations nitrogen cycling nitrogen use efficiency
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Communities and Quantitative Analysis of Ammonia-oxidizing Organisms in Pearl River Estuary Sediments
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作者 陈金全 郑燕平 +1 位作者 姜丽晶 王风平 《Agricultural Science & Technology》 CAS 2012年第10期2080-2083,2087,共5页
[Objective] This study aimed to investigate the abundance and composition of ammonia-oxidizing bacteria and ammonia-oxidizing archaea in Pearl River Estuary sediment.[Method] Firstly,the amoA gene library was construc... [Objective] This study aimed to investigate the abundance and composition of ammonia-oxidizing bacteria and ammonia-oxidizing archaea in Pearl River Estuary sediment.[Method] Firstly,the amoA gene library was constructed;then based on that,the content and diversity of amoA genes of ammonia-oxidizing bacteria and ammonia-oxidizing archaea in Pearl River Estuary sediment were detected by using quantitative real-time polymerase chain reaction(Q-PCR).[Result] The results of Q-PCR presented that ammonia-oxidizing archaea(AOA) were more abundant than ammonia-oxidizing bacteria(AOB) in the top of sediment cores,with ratios of AOA to AOB of 22 and 9 at the two sites.It suggested that ammonia-oxidizing archaea may play more important roles than ammonia-oxidizing bacteria in the process of ammonia oxidation in the Pearl River Estuary sediment.The phylogenetic tree based on amoA gene sequences revealed that the amoA sequences of both AOA and AOB shared high similarity with the clones from uncultured environment.In the top sediment layer at site Q7,AOB amoA-like gene sequences were dominated by Nitrosomonas-like sequence types,which could be classified into five groups(clusters A,B,C,D and E).Cluster A accounted for 72.1% of the library.In the top sediment layer,the AOA amoA gene fell into two groups "water column/sediment" cluster(52.2%) and "soil/sediment" cluster(47.8%).But in the bottom sediment layer of Q7,most of the AOA amoA sequences(93.3%) fell into "soil/sediment" cluster,and a little part(6.7%) fell into the "water/sediment" cluster.In addition,the total amount of amoA genes in the bottom sediment was higher than that in top sediment.[Conclusion] This study helps to realize the cycle of nitrogen in Pearl River Estuary Region,and thus to provide theoretical support for the treatment of nitrogen eutrophication. 展开更多
关键词 Pearl River Estuary sediment ammonia oxidation amoA gene Q-PCR
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Seed-induced synthesis of small-crystal TS-1 using ammonia as alkali source 被引量:11
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作者 薛腾 刘华萍 +3 位作者 王一萌 吴海虹 吴鹏 何鸣元 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2015年第11期1928-1935,共8页
Small-crystal TS-1 was synthesized via a seed-induced approach using ammonia as the alkali source and tetrapropylammonium bromide as an auxiliary structure-directing agent. The TS-1 samples were characterized using X-... Small-crystal TS-1 was synthesized via a seed-induced approach using ammonia as the alkali source and tetrapropylammonium bromide as an auxiliary structure-directing agent. The TS-1 samples were characterized using X-ray diffraction, N2 adsorption-desorption, Fourier-transform infrared spectroscopy, inductively coupled plasma atomic emission spectroscopy, scanning electron microscopy, and ultraviolet-visible spectroscopy. The use of the colloidal seed reduced the crystal size, and an appropriate amount of silicalite-1 seed assisted Ti incorporation into the TS-1 framework. This method reduces the cost of TS- 1 synthesis because a significantly smaller amount of tetrapropylammonium hydroxide is used. The catalytic performance of the synthesized small-crystal TS-1 samples in cyclohexanone ammoximation was better than that of bulk TS-1 as a result of improved diffusion and a larger number of active tetrahedral Ti centers. 展开更多
关键词 Small crystal TS- 1 molecular sieve Seed-induced synthesis ammonia Catalytic oxidation Cyclohexanone ammoximation
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Hydrogen generation from ammonia electrolysis on bifunctional platinum nanocubes electrocatalysts 被引量:9
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作者 Hui-Ying Sun Guang-Rui Xu +4 位作者 Fu-Min Li Qi ng-Li ng Hong Pu-Jun Jin Pei Chen Yu Chen 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2020年第8期234-240,I0009,共8页
The ammonia electrolysis is a highly efficient and energy-saving method for ultra-pure hydrogen generation, which highly relies on electrocatalytic performance of electrocatalysts. In this work, high-quality platinum(... The ammonia electrolysis is a highly efficient and energy-saving method for ultra-pure hydrogen generation, which highly relies on electrocatalytic performance of electrocatalysts. In this work, high-quality platinum(Pt) nanocubes(Pt-NCs) with 4.5 nm size are achieved by facile hydrothermal synthesis. The physical morphology and structure of Pt-NCs are exhaustively characterized, revealing that Pt-NCs with special {100} facets have excellent uniformity, good dispersity and high crystallinity. Meanwhile, the electrocatalytic performance of Pt-NCs for ammonia electrolysis are carefully investigated in alkaline solutions, which display outstanding electroactivity and stability for both ammonia electrooxidation reaction(AEOR) and hydrogen evolution reaction(HER) in KOH solution. Furthermore, a symmetric Pt-NCs||Pt-NCs ammonia electrolyzer based on bifunctional Pt-NCs electrocatalyst is constructed, which only requires 0.68 V electrolysis voltage for hydrogen generation. Additionally, the symmetric Pt-NCs||Pt-NCs ammonia electrolyzer has excellent reversible switch capability for AEOR at anode and HER at cathode, showing outstanding alternating operation ability for ammonia electrolysis. 展开更多
关键词 ammonia electrolysis Water electrolysis ammonia oxidation reaction Hydrogen evolution reaction Platinum nanocubes
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Community analysis of ammonia oxidizer in the oxygen-limited nitritation stage of OLAND system by DGGE of PCR amplified 16S rDNA fragments and FISH 被引量:17
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作者 ZHANGDan ZHANGDe-min +2 位作者 LIUYao-ping CAOWen-wei CHENGuan-xiong 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2004年第5期838-842,共5页
OLAND(oxygen limited autotrophic nitrification and denitrification) nitrogen removal system was constructed by coupling with oxygen limited nitritation stage and anaerobic ammonium oxidation stage. Ammonia oxidizer, a... OLAND(oxygen limited autotrophic nitrification and denitrification) nitrogen removal system was constructed by coupling with oxygen limited nitritation stage and anaerobic ammonium oxidation stage. Ammonia oxidizer, as a kind of key bacteria in N cycle, plays an important role at the oxygen limited nitritation stage of OLAND nitrogen removal system. In this study, specific amplification of 16S rDNA fragment of ammonia oxidizer by nested PCR, separation of mixed PCR samples by denaturing gradient gel electrophoresis(DGGE), and the quantification of ammonia oxidizer by fluorescence in situ hybridization(FISH) were combined to investigate the shifts of community composition and quantity of ammonia oxidizer of the oxygen limited nitritation stage in OLAND system. It showed that the community composition of ammonia oxidizer changed drastically when dissolved oxygen was decreased gradually, and the dominant ammonia oxidizer of the steady nitrite accumulation stage were completely different from that of the early stage of oxygen limited nitritation identified by DGGE . It was concluded that the Nitrosomonas may be the dominant genus of ammonia oxidizer at the oxygen limited nitritation stage of OLAND system characterized by nested PCR-DGGE and FISH, and the percentage of Nitrosomonas was 72.5% ±0.8% of ammonia oxidizer at the steady nitrite accumulation stage detected by FISH. 展开更多
关键词 OLAND NITRITATION ammonia oxidizer DGGE FISH
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Impact of Long-Term Fertilization on Community Structure of Ammonia Oxidizing and Denitrifying Bacteria Based on amoA and nirK Genes in a Rice Paddy from Tai Lake Region,China 被引量:9
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作者 JIN Zhen-jiang LI Lian-qing +3 位作者 LIU Xiao-yu PAN Gen-xing Qaiser Hussein LIU Yong-zhuo 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2014年第10期2286-2298,共13页
Ammonia oxidizing (AOB) and denitrifying bacteria (DNB) play an important role in soil nitrogen transformation in natural and agricultural ecosystems. Effects of long-term fertilization on abundance and community ... Ammonia oxidizing (AOB) and denitrifying bacteria (DNB) play an important role in soil nitrogen transformation in natural and agricultural ecosystems. Effects of long-term fertilization on abundance and community composition of AOB and DNB were studied with targeting ammonia monooxygenase (amoA) and nitrite reductase (nirK) genes using polymerase chain reaction- denaturing gradient gel electrophoresis (PCR-DGGE) and real-time PCR, respectively. A field trial with different fertilization treatments in a rice paddy from Tai Lake region, centre East China was used in this study, including no fertilizer application (NF), balanced chemical fertilizers (CF), combined organic/inorganic fertilizer of balanced chemical fertilizers plus pig manure (CFM), and plus rice straw return (CFS). The abundances and riehnesses of amoA and nirK were increased in CF, CFM and CFS compared to NF. Principle component analysis of DGGE profiles showed significant difference in nirK and amoA genes composition between organic amended (CFS and CFM) and the non-organic amended (CF and NF) plots. Number of amoA copies was significantly positively correlated with normalized soil nutrient richness (NSNR) of soil organic carbon (SOC) and total nitrogen (T-N), and that of nirK copies was with NSNR of SOC, T-N plus total phosphorus. Moreover, nitrification potential showed a positive correlation with SOC content, while a significantly lower denitrification potential was found under CFM compared to under CFS. Therefore, SOC accumulation accompanied with soil nutrient richness under long-term balanced and organic/inorganic combined fertilization promoted abundance and diversity of AOB and DNB in the rice paddy. 展开更多
关键词 long-term fertilization ammonia oxidizing bacteria denitrifying bacteria abundance rice paddy
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Urea Preparation by Oxidative Carbonylation of Ammonia 被引量:2
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作者 A.R. Elman V.I. Smirnov 《Journal of Environmental Science and Engineering》 2011年第8期1006-1012,共7页
Effective one-stage method of urea preparation by catalytic oxidative carbonylation of ammonia in liquid phase is developed. The method allows to prepare urea with productivity of-530 g/(L·h) in sufficiently mi... Effective one-stage method of urea preparation by catalytic oxidative carbonylation of ammonia in liquid phase is developed. The method allows to prepare urea with productivity of-530 g/(L·h) in sufficiently mild conditions (total pressure -30 bar, 45 ℃). The process is characterized by high selectivity (near 100%) i.e. byproducts separation is not needed. Almost all CO is consumed during the process, this substantially diminishes the waste-gas purification costs and raises the process environmental characteristics; the only byproduct is water. 展开更多
关键词 UREA ammonia oxidative carbonylation SELENIUM heat efficiency
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Nitrogen mobility,ammonia volatilization,and estimated leaching loss from long-term manure incorporation in red soil 被引量:10
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作者 HUANG Jing DUAN Ying-hua +6 位作者 XU Ming-gang ZHAI Li-mei ZHANG Xu-bo WANG Bo-ren ZHANG Yang-zhu GAO Su-duan SUN Nan 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2017年第9期2082-2092,共11页
Nitrogen(N) loss from fertilization in agricultural fields has an unavoidable negative impact on the environment and a better understanding of the major pathways can assist in developing the best management practice... Nitrogen(N) loss from fertilization in agricultural fields has an unavoidable negative impact on the environment and a better understanding of the major pathways can assist in developing the best management practices. The aim of this study was to evaluate the fate of N fertilizers applied to acidic red soil(Ferralic Cambisol) after 19 years of mineral(synthetic) and manure fertilizer treatments under a cropping system with wheat-maize rotations. Five field treatments were examined: control(CK), chemical nitrogen and potash fertilizer(NK), chemical nitrogen and phosphorus fertilizer(NP), chemical nitrogen, phosphorus and potash fertilizer(NPK) and the NPK with manure(NPKM, 70% N from manure). Based on the soil total N storage change in 0–100 cm depth, ammonia(NH_3) volatilization, nitrous oxide(N_2O) emission, N plant uptake, and the potential N leaching loss were estimated using a mass balance approach. In contrast to the NPKM, all mineral fertilizer treatments(NK, NP and NPK) showed increased nitrate(NO_3~–) concentration with increasing soil depth, indicating higher leaching potential. However, total NH_3 volatilization loss was much higher in the NPKM(19.7%) than other mineral fertilizer treatments(≤4.2%). The N_2O emissions were generally low(0.2–0.9%, the highest from the NPKM). Total gaseous loss accounted for 1.7, 3.3, 5.1, and 21.9% for NK, NP, NPK, and NPKM treatments, respectively. Estimated N leaching loss from the NPKM was only about 5% of the losses from mineral fertilizer treatments. All data demonstrated that manure incorporation improved soil productivity, increased yield, and reduced potential leaching, but with significantly higher NH_3 volatilization, which could be reduced by improving the application method. This study confirms that manure incorporationis an essential strategy in N fertilization management in upland red soil cropping system. 展开更多
关键词 soil NO_3~–-N ammonia volatilization nitrogen leaching long-term field experiment mass balance nitrous oxide emission
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