In recent years,in order to improve nutrient use efficiency,especially nitrogen use efficiency,fertilizer valueadded technology has been developed rapidly.However,the mechanism of the effect of synergistic fertilizer ...In recent years,in order to improve nutrient use efficiency,especially nitrogen use efficiency,fertilizer valueadded technology has been developed rapidly.However,the mechanism of the effect of synergistic fertilizer on plant nitrogen utilization is not clear.A study was,therefore,conducted to explore the activities and gene expression of key enzymes for nitrogen assimilation and the gene expression of nitrogen transporters in wheat after the application of synergistic fertilizer.Soil column experiment was set up in Qingdao Agricultural University experimental base from October 2018 to June 2019.Maleic acid and itaconic acid were copolymerized with acrylic acid as cross-linking monomer to make a fluid gel,which was sprayed on the fertilizer surface to make nitrogen and phosphorus synergistic fertilizer.A total of 6 treatments was set according to different nitrogen and phosphorus fertilizer ratios:(1)100%common nitrogen fertilizer+100%common phosphate fertilizer(2)70%nitrogen synergistic fertilizer+100%phosphorus synergistic fertilizer;(3)100%nitrogen synergistic fertilizer+70%phosphorus synergistic fertilizer;(4)100%nitrogen synergistic fertilizer+100%phosphorus synergistic fertilizer;(5)70%nitrogen synergistic fertilizer+70%phosphorus synergistic fertilizer;(6)100%commercial nitrogen synergistic fertilizer+100%commercial phosphorus synergistic fertilizer.The results are as follows:(1)the enzyme activities of wheat plants under synergistic fertilizer condition were higher than those under ordinary fertilizer,except under the treatment that nitrogen and phosphorus synergistic fertilizer were both reduced;(2)the expression level of the genes under the treatment“100%nitrogen synergistic fertilizer+100%phosphorus synergistic fertilizer”was significantly higher than those in other treatments.Combined with the higher performance of nitrogen concentration in various parts of the plant under the condition of applying synergistic fertilizer,this study indicated that the application of synergistic fertilizer can improve the nitrogen metabolism of the plant by increasing the nitrogen level in the rhizosphere soil,inducing the expression of nitrogen transporter genes and key assimilation enzymes genes.展开更多
An increase in atmospheric nitrogen (N) deposition can promote soil acidification, which may increase the release of ethylene (C2H4) under forest floors. Unfortunately, knowledge of whether increasing N deposition...An increase in atmospheric nitrogen (N) deposition can promote soil acidification, which may increase the release of ethylene (C2H4) under forest floors. Unfortunately, knowledge of whether increasing N deposition and C2H4 releases have synergistic effects on soil methane (CH4) uptake is limited and certainly deserves to be examined. We conducted some field measurements and laboratory experiments to examine this issue. The addition of (NH4)2SO4 or NH4Cl at a rate of 45 kg N ha-1 yr-1 reduced the soil CH4 uptake under a temperate old-growth forest in northeast China, and there were synergistic effects of N amendments in the presence of C2H4 concentrations equal to atmospheric CH4 concentration on the soil CH4 uptake, particularly in the NH4Cl-treated plots. Effective concentrations of added C2H4 on the soil CH4 uptake were smaller in NH+4 -treated plots than in KNO3-treated plots. The concentration of ca 0.3 μl C2H4 L-1 in the headspace gases reduced by 20% soil atmospheric CH4 uptake in the NH4Cl-treated plots, and this concentration was easily produced in temperate forest topsoils under short-term anoxic conditions. Together with short-term stimulating effects of N amendments and soil acidification on C2H4 production from forest soils, our observations suggest that knowledge of synergistic effects of NH+4 , rather than NO3- , amendments and C2H4 on the in situ soil CH4 uptake is critical for understanding the role of atmospheric N deposition and cycling of C2H4 under forest floors in reducing global atmospheric CH4 uptake by forests. Synergistic functions of NH4+ -N deposition and C2H4 release due to soil acidification in reducing atmospheric CH4 uptake by forests are discussed.展开更多
The nitrogen and sulfur co-doped carbon dots(N, S-CDs) with increased luminescence were synthesized by a hydrothermal process in one green pot by using glucose, and a new sulfur-doping source of sodium sulfite was dev...The nitrogen and sulfur co-doped carbon dots(N, S-CDs) with increased luminescence were synthesized by a hydrothermal process in one green pot by using glucose, and a new sulfur-doping source of sodium sulfite was developed.The synergistic effect of the N and S groups was well discussed through the structure analysis of Fourier transform infrared spectra and x-ray photoelectron spectra. The surface states of N, S-CDs embody more complicated functional groups, and S element exists as –SSO3, –C–SO3, and SO-42groups due to the introduction of sodium sulfite. The sulfur-containing groups passivate the surface of the CDs, and the relatively high sulfur groups may reduce the non-radiation centers. The fluorescence is affected by the hydroxyl group of the solvent. The quenching of Fe3+ ion to fluorescence and the sensitivity of fluorescence to p H were also investigated.展开更多
The Zhalong wetland,a Ramsar listed wetland in China,which is located in the lower reaches of theWuyu’er River,perennially takes in lots of nutrient input of N and P from around the catchment.Nutrient substanceswere ...The Zhalong wetland,a Ramsar listed wetland in China,which is located in the lower reaches of theWuyu’er River,perennially takes in lots of nutrient input of N and P from around the catchment.Nutrient substanceswere especially accumulated in the shallowlakes owning to the low-lying topography.The Xianhe Lake,where is loca-ted in buffer zone of the Zhalong wetland reserve,was chosen as our target area.The spatial variation of nutrient sub-stances in the shallow lakes was discussed and its influence factors were pointed out.The results showed that nitrogenand phosphorus in the wetland water existed mainly in the form of organic ones.The concentration of total nitrogen(TN)ranged from 0.65 mg/L to 10.64 mg/L and total phosphorus(TP) ranged from 0.013 mg/L to 0.052 mg/L.Ratio ofN/P was between 25.6 and 206.5.The water quality of the Xianhe Lake has been contaminated and is in heavy eutroph-ication.Total P has been acting as the major limiting factor.The distribution pattern of nitrogen and phosphorus in wet-land water showed characteristics of internal release except for the stream mouth area.There,the vertical distributions ofnitrogen and phosphorus nutrients were from both exterior source and internal release,and was mainly influenced by ex-terior source during flood period.Strong hydrodynamic disturb contributed to nitrogen and phosphorus nutrients suspen-ding and releasing in the sediments.The nutrients distribution in the water varied independent on regional changes ofdifferent frequency of hydrodynamic disturb.Mineralization and denitrification might be promoted in high frequency hy-drodynamic disturb area.In growing period,the absorption ofPhragmitesto nutrients was an important mechanism of nu-trients descending and spatial variation in the shallow lake.展开更多
The rhizosphere is the most active soil area for material transformation and energy flow of soil,root,and microorganism,which plays an important role in soil biochemical cycling.Although the rhizospheric nitrogen(N)an...The rhizosphere is the most active soil area for material transformation and energy flow of soil,root,and microorganism,which plays an important role in soil biochemical cycling.Although the rhizospheric nitrogen(N)and phosphorous(P)were easily disturbed in the agroecosystem,the effects of rhizosphere on the dynamics of soil N and P cycling have not yet been systematically quantified globally.We summarized the magnitude,direction,and driving forces of rhizosphere effects on agroecosystem's N and P dynamics by 1063 observations and 15 variables from 122 literature.Rhizosphere effects increased available N(AN,9%),available P(AP,11%),and total P(TP,5%),and decreased nitrate N(NO_(3)-N,18%)and ammonia N(NH_(4)-N,16%).The effect of rhizosphere on total N(TN)was not significant.These effects improved AN in tropical(12%)and subtropical(14%)regions.The effect of rhizosphere on TP was greater under subtropical conditions than in other climates.The most substantial effects of the rhizosphere on TP and AP were observed under humid conditions.Rhizosphere effects increased AN and AP in vegetables more than in other crop systems.Application of N>30o kg ha^(-1) had the most significant and positive rhizosphere effects on TN and AN.P application of 100-150 kg ha^(-1) had the greatest rhizosphere effects on TP and AP.These effects also improved the microbial(biomass N and P)and enzymatic aspects(urease,acid phosphatase,and alkaline phosphatase)of soil P and N cycling.Structural equation modeling suggested that aridity indices,fertilizer application rate,soil pH,microbial biomass,and soil enzymes strongly influence the magnitude and direction of the rhizosphere's effect on the P and N cycles.Overall,these findings are critical for improving soil nutrient utilization efficiency and modeling nutrient cycling in the rhizosphereforagricultural systems.展开更多
合成氨(NH_(3))的发展是现代工业进程和人类生存的基石。受氮气(N_(2))化学惰性的限制,当前的合成氨工业能源消耗高并且排放大量的二氧化碳。电化学氮气还原反应(NRR),是有望取代高能耗的Haber-Bosch(HB)合成法的一种绿色可持续的合成...合成氨(NH_(3))的发展是现代工业进程和人类生存的基石。受氮气(N_(2))化学惰性的限制,当前的合成氨工业能源消耗高并且排放大量的二氧化碳。电化学氮气还原反应(NRR),是有望取代高能耗的Haber-Bosch(HB)合成法的一种绿色可持续的合成氨工艺。然而,因氮气以及析氢竞争富反应(HER)导致电催化氮气还原极低的NH_(3)产率和能量转换效率一直是目前人工固氮领域面临的挑战。在本文中,我们报道了一种具有丰富孔结构的磷掺杂碳(PC)负载Zn_(3)(PO_(4))_(2)/Zn_(2)P_(2)O_(7)纳米复合材料(h-PC/Zn_(3)(PO_(4))_(2)/Zn_(2)P_(2)O_(7)),在酸性和中性介质中将N_(2)高效催化转化为NH_(3)。其独特的分级多孔结构提高了表面粗糙度并加快了氮气在催化剂体相中的扩散,这有利于延长氮气在催化剂表面的停留时间以及提高活性位点的利用效率。而多组分的均匀分布可以调节电子结构并优化反应中间体的吸附行为,进而提高活性位点的本征活性。在0.1mol·L^(-1)HCI电解液中,h-PC/Zn_(3)(PO_(4))_(2)/Zn_(2)P_(2)O_(7)在-0.2 V vs.可逆氢电极(RHE)电位下NH_(3)的产率可以达到38.7±1.2μg·h^(-1)·mgcat^(-1),法拉第效率为19.8%±0.9%。此外;h-PC/Zn_(3)(PO_(4))_(2)/Zn_(2)P_(2)O_(7)在0.1 mol·L^(-1)Na_(2)SO_(4)溶液中同样展现出优异的电催化氮气还原合成氨性能,NH_(3)产率及法拉第效率分别为17.1±0.8μg·h^(-1)·mgcat^(-1)和15.g%±0.6%,明显优于PC/Zn_(3)P_(2)、C/ZnO和大多数报道的非贵金属电催化剂。这种优异的性能主要归因于多孔结构有利于传质及多组分活性位点协同效应。此外,我们采用非原位X射线光电子能谱(XPS)、透射电子显微镜(TEM)和X射线衍射(XRD)等表征手段对NRR测试前后h-PC/Zn_(3)(PO_(4))_(2)/Zn_(2)P_(2)O_(7)的组成和结构变化进行了剖析。在反应后检测到了新增的N物种信号,证明催化剂确实发生了氮气还原反应。本研究提供了一种通过同步构建传质通道并耦合不同的活性位点以协同增强NRR活性和选择性的新思路,这对加快绿色制氨工业化具有重大意义。展开更多
Oxidation-absorption technology is a key step for NOxremoval from low-temperature gas.Under the condition of low O_(3)concentration(O_(3)/NO molar ratio = 0.6), F-TiO_(2)(F-TiO_(2)), which is cheap and environmentally...Oxidation-absorption technology is a key step for NOxremoval from low-temperature gas.Under the condition of low O_(3)concentration(O_(3)/NO molar ratio = 0.6), F-TiO_(2)(F-TiO_(2)), which is cheap and environmentally friendly, has been prepared as ozonation catalysts for NO oxidation. Catalytic activity tests performed at 120℃showed that the NO oxidation efficiency of F-TiO_(2)samples was higher than that of TiO_(2)(about 43.7%), and the NO oxidation efficiency of F-TiO_(2)-0.15 was the highest, which was 65.3%. Combined with physicochemical characteristics of catalysts and the analysis of active species, it was found that there was a synergistic effect between F sites and oxygen vacancies on F-TiO_(2), which could accelerate the transformation of monomolecular O_(3)into multi-molecule singlet oxygen(1O_(2)), thus promoting the selective oxidation of NO to NO_(2). The oxidation reaction of NO on F-TiO_(2)-0.15 follows the Eley-Rideal mechanism, that is, gaseous NO reacts with adsorbed O_(3)and finally form NO_(2).展开更多
In order to explore the effects of different silicon preparations on the soil fertility of paddy fields,a pot experiment with Dongnong 427 was carried on.Different types of silicon preparations,including Si-50-G,Si-60...In order to explore the effects of different silicon preparations on the soil fertility of paddy fields,a pot experiment with Dongnong 427 was carried on.Different types of silicon preparations,including Si-50-G,Si-60-G,Si-RH,Si-50 and Si-60,were sprayed on the leaves of rice at the tillering stage,and CK was set in the control stage.The contents of alkali nitrogen,available phosphorus,available potassium and available silicon in soil were determined in the tillering stage,booting stage and maturity stage of rice.The results showed that spraying different silicon preparations at the tillering stage could promote the activation and release of soil available nutrients in different degrees.展开更多
A novel Ag@nitrogen-doped porous carbon(Ag-NPC) composite was synthesized via a facile hydrothermal method and applied as an anode material in lithium-ion batteries(LIBs). Using this method, Ag nanoparticles(Ag NPs) w...A novel Ag@nitrogen-doped porous carbon(Ag-NPC) composite was synthesized via a facile hydrothermal method and applied as an anode material in lithium-ion batteries(LIBs). Using this method, Ag nanoparticles(Ag NPs) were embedded in NPC through thermal decomposition of Ag NO_3 in the pores of NPC. The reversible capacity of Ag-NPC remained at 852 m Ah g^(-1)after 200 cycles at a current density of 0.1 A g^(-1), showing its remarkable cycling stability. The enhancement of the electrochemical properties such as cycling performance,reversible capacity and rate performance of Ag-NPC compared to the NPC contributed to the synergistic effects between Ag NPs and NPC.展开更多
以葡萄糖为碳源、NaNO3为模板和造孔剂,通过高温炭化法以及NH3高温后处理合成了多级孔氮掺杂碳材料NC-X-T[X为NaNO3与葡萄糖的质量比,T为温度(℃)]。采用N2吸附-脱附、XRD、XPS、SEM、TEM对NC-X-T的比表面积、孔径分布、晶体结构、化学...以葡萄糖为碳源、NaNO3为模板和造孔剂,通过高温炭化法以及NH3高温后处理合成了多级孔氮掺杂碳材料NC-X-T[X为NaNO3与葡萄糖的质量比,T为温度(℃)]。采用N2吸附-脱附、XRD、XPS、SEM、TEM对NC-X-T的比表面积、孔径分布、晶体结构、化学组成以及形貌进行了表征与测试。以NC-X-T为催化剂、过硫酸氢钾(PMS)为氧化剂,在不同条件下进行了苯酚的降解。结果表明,造孔和掺氮过程的协同可极大提升NC-X-T的催化性能。0.005 g NC-0.5-800及质量浓度1.0 g/L PMS在40 min内可将100 mL 5.3×10^(–4)mol/L苯酚完全降解,反应速率常数高达0.397 min^(–1),优于大多数金属及非金属催化剂。利用XPS对降解过程中NC-X-T的稳定性进行了研究,证实碳材料的氧化是其失活的主要原因,经过高温无氧处理可以恢复其部分催化活性。展开更多
Phosphorus has recently received extensive attention as a promising anode for lithium ion batteries (LIB ) due to its high theoretical capacity of 2,596
基金supported by the Program of Shandong Modern Agricultural Technology and Industry System–Cultivation and Soil Fertilizer(SDAIT0107)the Major Application Technology Innovation Projects in Shandong Province and the Key Research and Development Projects of Shandong Province.
文摘In recent years,in order to improve nutrient use efficiency,especially nitrogen use efficiency,fertilizer valueadded technology has been developed rapidly.However,the mechanism of the effect of synergistic fertilizer on plant nitrogen utilization is not clear.A study was,therefore,conducted to explore the activities and gene expression of key enzymes for nitrogen assimilation and the gene expression of nitrogen transporters in wheat after the application of synergistic fertilizer.Soil column experiment was set up in Qingdao Agricultural University experimental base from October 2018 to June 2019.Maleic acid and itaconic acid were copolymerized with acrylic acid as cross-linking monomer to make a fluid gel,which was sprayed on the fertilizer surface to make nitrogen and phosphorus synergistic fertilizer.A total of 6 treatments was set according to different nitrogen and phosphorus fertilizer ratios:(1)100%common nitrogen fertilizer+100%common phosphate fertilizer(2)70%nitrogen synergistic fertilizer+100%phosphorus synergistic fertilizer;(3)100%nitrogen synergistic fertilizer+70%phosphorus synergistic fertilizer;(4)100%nitrogen synergistic fertilizer+100%phosphorus synergistic fertilizer;(5)70%nitrogen synergistic fertilizer+70%phosphorus synergistic fertilizer;(6)100%commercial nitrogen synergistic fertilizer+100%commercial phosphorus synergistic fertilizer.The results are as follows:(1)the enzyme activities of wheat plants under synergistic fertilizer condition were higher than those under ordinary fertilizer,except under the treatment that nitrogen and phosphorus synergistic fertilizer were both reduced;(2)the expression level of the genes under the treatment“100%nitrogen synergistic fertilizer+100%phosphorus synergistic fertilizer”was significantly higher than those in other treatments.Combined with the higher performance of nitrogen concentration in various parts of the plant under the condition of applying synergistic fertilizer,this study indicated that the application of synergistic fertilizer can improve the nitrogen metabolism of the plant by increasing the nitrogen level in the rhizosphere soil,inducing the expression of nitrogen transporter genes and key assimilation enzymes genes.
基金funded jointly by the National Natural Science Foundation of China (Grant Nos. 41021004, 20777071 and 20477044)the Key Project of Knowledge Innovation Program from the Chinese Academy of Sciences (KZCX2-YW-432)the Hundred Talents Project from the Chinese Academy of Sciences
文摘An increase in atmospheric nitrogen (N) deposition can promote soil acidification, which may increase the release of ethylene (C2H4) under forest floors. Unfortunately, knowledge of whether increasing N deposition and C2H4 releases have synergistic effects on soil methane (CH4) uptake is limited and certainly deserves to be examined. We conducted some field measurements and laboratory experiments to examine this issue. The addition of (NH4)2SO4 or NH4Cl at a rate of 45 kg N ha-1 yr-1 reduced the soil CH4 uptake under a temperate old-growth forest in northeast China, and there were synergistic effects of N amendments in the presence of C2H4 concentrations equal to atmospheric CH4 concentration on the soil CH4 uptake, particularly in the NH4Cl-treated plots. Effective concentrations of added C2H4 on the soil CH4 uptake were smaller in NH+4 -treated plots than in KNO3-treated plots. The concentration of ca 0.3 μl C2H4 L-1 in the headspace gases reduced by 20% soil atmospheric CH4 uptake in the NH4Cl-treated plots, and this concentration was easily produced in temperate forest topsoils under short-term anoxic conditions. Together with short-term stimulating effects of N amendments and soil acidification on C2H4 production from forest soils, our observations suggest that knowledge of synergistic effects of NH+4 , rather than NO3- , amendments and C2H4 on the in situ soil CH4 uptake is critical for understanding the role of atmospheric N deposition and cycling of C2H4 under forest floors in reducing global atmospheric CH4 uptake by forests. Synergistic functions of NH4+ -N deposition and C2H4 release due to soil acidification in reducing atmospheric CH4 uptake by forests are discussed.
基金Project by the National Natural Science Foundation of China(Grant Nos.51571085,11805052,and 61705062)the Research Project for Basic and Forefront Technology of Henan Province,China(Grant No.162300410219)the Doctor Foundation of Henan Polytechnic University,China(Grant No.B2014049)
文摘The nitrogen and sulfur co-doped carbon dots(N, S-CDs) with increased luminescence were synthesized by a hydrothermal process in one green pot by using glucose, and a new sulfur-doping source of sodium sulfite was developed.The synergistic effect of the N and S groups was well discussed through the structure analysis of Fourier transform infrared spectra and x-ray photoelectron spectra. The surface states of N, S-CDs embody more complicated functional groups, and S element exists as –SSO3, –C–SO3, and SO-42groups due to the introduction of sodium sulfite. The sulfur-containing groups passivate the surface of the CDs, and the relatively high sulfur groups may reduce the non-radiation centers. The fluorescence is affected by the hydroxyl group of the solvent. The quenching of Fe3+ ion to fluorescence and the sensitivity of fluorescence to p H were also investigated.
基金President Scholarship of Chinese Academy of Sciences
文摘The Zhalong wetland,a Ramsar listed wetland in China,which is located in the lower reaches of theWuyu’er River,perennially takes in lots of nutrient input of N and P from around the catchment.Nutrient substanceswere especially accumulated in the shallowlakes owning to the low-lying topography.The Xianhe Lake,where is loca-ted in buffer zone of the Zhalong wetland reserve,was chosen as our target area.The spatial variation of nutrient sub-stances in the shallow lakes was discussed and its influence factors were pointed out.The results showed that nitrogenand phosphorus in the wetland water existed mainly in the form of organic ones.The concentration of total nitrogen(TN)ranged from 0.65 mg/L to 10.64 mg/L and total phosphorus(TP) ranged from 0.013 mg/L to 0.052 mg/L.Ratio ofN/P was between 25.6 and 206.5.The water quality of the Xianhe Lake has been contaminated and is in heavy eutroph-ication.Total P has been acting as the major limiting factor.The distribution pattern of nitrogen and phosphorus in wet-land water showed characteristics of internal release except for the stream mouth area.There,the vertical distributions ofnitrogen and phosphorus nutrients were from both exterior source and internal release,and was mainly influenced by ex-terior source during flood period.Strong hydrodynamic disturb contributed to nitrogen and phosphorus nutrients suspen-ding and releasing in the sediments.The nutrients distribution in the water varied independent on regional changes ofdifferent frequency of hydrodynamic disturb.Mineralization and denitrification might be promoted in high frequency hy-drodynamic disturb area.In growing period,the absorption ofPhragmitesto nutrients was an important mechanism of nu-trients descending and spatial variation in the shallow lake.
基金supported by National Natural Science Foundation of China(42007073)。
文摘The rhizosphere is the most active soil area for material transformation and energy flow of soil,root,and microorganism,which plays an important role in soil biochemical cycling.Although the rhizospheric nitrogen(N)and phosphorous(P)were easily disturbed in the agroecosystem,the effects of rhizosphere on the dynamics of soil N and P cycling have not yet been systematically quantified globally.We summarized the magnitude,direction,and driving forces of rhizosphere effects on agroecosystem's N and P dynamics by 1063 observations and 15 variables from 122 literature.Rhizosphere effects increased available N(AN,9%),available P(AP,11%),and total P(TP,5%),and decreased nitrate N(NO_(3)-N,18%)and ammonia N(NH_(4)-N,16%).The effect of rhizosphere on total N(TN)was not significant.These effects improved AN in tropical(12%)and subtropical(14%)regions.The effect of rhizosphere on TP was greater under subtropical conditions than in other climates.The most substantial effects of the rhizosphere on TP and AP were observed under humid conditions.Rhizosphere effects increased AN and AP in vegetables more than in other crop systems.Application of N>30o kg ha^(-1) had the most significant and positive rhizosphere effects on TN and AN.P application of 100-150 kg ha^(-1) had the greatest rhizosphere effects on TP and AP.These effects also improved the microbial(biomass N and P)and enzymatic aspects(urease,acid phosphatase,and alkaline phosphatase)of soil P and N cycling.Structural equation modeling suggested that aridity indices,fertilizer application rate,soil pH,microbial biomass,and soil enzymes strongly influence the magnitude and direction of the rhizosphere's effect on the P and N cycles.Overall,these findings are critical for improving soil nutrient utilization efficiency and modeling nutrient cycling in the rhizosphereforagricultural systems.
文摘合成氨(NH_(3))的发展是现代工业进程和人类生存的基石。受氮气(N_(2))化学惰性的限制,当前的合成氨工业能源消耗高并且排放大量的二氧化碳。电化学氮气还原反应(NRR),是有望取代高能耗的Haber-Bosch(HB)合成法的一种绿色可持续的合成氨工艺。然而,因氮气以及析氢竞争富反应(HER)导致电催化氮气还原极低的NH_(3)产率和能量转换效率一直是目前人工固氮领域面临的挑战。在本文中,我们报道了一种具有丰富孔结构的磷掺杂碳(PC)负载Zn_(3)(PO_(4))_(2)/Zn_(2)P_(2)O_(7)纳米复合材料(h-PC/Zn_(3)(PO_(4))_(2)/Zn_(2)P_(2)O_(7)),在酸性和中性介质中将N_(2)高效催化转化为NH_(3)。其独特的分级多孔结构提高了表面粗糙度并加快了氮气在催化剂体相中的扩散,这有利于延长氮气在催化剂表面的停留时间以及提高活性位点的利用效率。而多组分的均匀分布可以调节电子结构并优化反应中间体的吸附行为,进而提高活性位点的本征活性。在0.1mol·L^(-1)HCI电解液中,h-PC/Zn_(3)(PO_(4))_(2)/Zn_(2)P_(2)O_(7)在-0.2 V vs.可逆氢电极(RHE)电位下NH_(3)的产率可以达到38.7±1.2μg·h^(-1)·mgcat^(-1),法拉第效率为19.8%±0.9%。此外;h-PC/Zn_(3)(PO_(4))_(2)/Zn_(2)P_(2)O_(7)在0.1 mol·L^(-1)Na_(2)SO_(4)溶液中同样展现出优异的电催化氮气还原合成氨性能,NH_(3)产率及法拉第效率分别为17.1±0.8μg·h^(-1)·mgcat^(-1)和15.g%±0.6%,明显优于PC/Zn_(3)P_(2)、C/ZnO和大多数报道的非贵金属电催化剂。这种优异的性能主要归因于多孔结构有利于传质及多组分活性位点协同效应。此外,我们采用非原位X射线光电子能谱(XPS)、透射电子显微镜(TEM)和X射线衍射(XRD)等表征手段对NRR测试前后h-PC/Zn_(3)(PO_(4))_(2)/Zn_(2)P_(2)O_(7)的组成和结构变化进行了剖析。在反应后检测到了新增的N物种信号,证明催化剂确实发生了氮气还原反应。本研究提供了一种通过同步构建传质通道并耦合不同的活性位点以协同增强NRR活性和选择性的新思路,这对加快绿色制氨工业化具有重大意义。
基金financially supported by the Natural Science Foundation for the Major National R & D projects of China (No.2017YFB0601805)the Higher Education Institutions of Anhui Province of China (Nos.KJ2020A0236, KJ2018A0638, andKJ2019A0079)the Open Project Program of Key Laboratory of Metallurgical Emission Reduction and Resources Recycling (Anhui University of Technology), Ministry of Education (No.JKF 20-04)。
文摘Oxidation-absorption technology is a key step for NOxremoval from low-temperature gas.Under the condition of low O_(3)concentration(O_(3)/NO molar ratio = 0.6), F-TiO_(2)(F-TiO_(2)), which is cheap and environmentally friendly, has been prepared as ozonation catalysts for NO oxidation. Catalytic activity tests performed at 120℃showed that the NO oxidation efficiency of F-TiO_(2)samples was higher than that of TiO_(2)(about 43.7%), and the NO oxidation efficiency of F-TiO_(2)-0.15 was the highest, which was 65.3%. Combined with physicochemical characteristics of catalysts and the analysis of active species, it was found that there was a synergistic effect between F sites and oxygen vacancies on F-TiO_(2), which could accelerate the transformation of monomolecular O_(3)into multi-molecule singlet oxygen(1O_(2)), thus promoting the selective oxidation of NO to NO_(2). The oxidation reaction of NO on F-TiO_(2)-0.15 follows the Eley-Rideal mechanism, that is, gaseous NO reacts with adsorbed O_(3)and finally form NO_(2).
基金Supported by the National Natural Science Foundation of China(31340032)。
文摘In order to explore the effects of different silicon preparations on the soil fertility of paddy fields,a pot experiment with Dongnong 427 was carried on.Different types of silicon preparations,including Si-50-G,Si-60-G,Si-RH,Si-50 and Si-60,were sprayed on the leaves of rice at the tillering stage,and CK was set in the control stage.The contents of alkali nitrogen,available phosphorus,available potassium and available silicon in soil were determined in the tillering stage,booting stage and maturity stage of rice.The results showed that spraying different silicon preparations at the tillering stage could promote the activation and release of soil available nutrients in different degrees.
基金supported by the Scientific and Technological Innovation Platform of Fujian Province(2006L2003)
文摘A novel Ag@nitrogen-doped porous carbon(Ag-NPC) composite was synthesized via a facile hydrothermal method and applied as an anode material in lithium-ion batteries(LIBs). Using this method, Ag nanoparticles(Ag NPs) were embedded in NPC through thermal decomposition of Ag NO_3 in the pores of NPC. The reversible capacity of Ag-NPC remained at 852 m Ah g^(-1)after 200 cycles at a current density of 0.1 A g^(-1), showing its remarkable cycling stability. The enhancement of the electrochemical properties such as cycling performance,reversible capacity and rate performance of Ag-NPC compared to the NPC contributed to the synergistic effects between Ag NPs and NPC.
文摘以葡萄糖为碳源、NaNO3为模板和造孔剂,通过高温炭化法以及NH3高温后处理合成了多级孔氮掺杂碳材料NC-X-T[X为NaNO3与葡萄糖的质量比,T为温度(℃)]。采用N2吸附-脱附、XRD、XPS、SEM、TEM对NC-X-T的比表面积、孔径分布、晶体结构、化学组成以及形貌进行了表征与测试。以NC-X-T为催化剂、过硫酸氢钾(PMS)为氧化剂,在不同条件下进行了苯酚的降解。结果表明,造孔和掺氮过程的协同可极大提升NC-X-T的催化性能。0.005 g NC-0.5-800及质量浓度1.0 g/L PMS在40 min内可将100 mL 5.3×10^(–4)mol/L苯酚完全降解,反应速率常数高达0.397 min^(–1),优于大多数金属及非金属催化剂。利用XPS对降解过程中NC-X-T的稳定性进行了研究,证实碳材料的氧化是其失活的主要原因,经过高温无氧处理可以恢复其部分催化活性。
基金Acknowledgements The authors are grateful for financial support from the Gobal Challenge Program grant (University of wollongong), Australia Auto CRC 2020, Creative Research Initiative (NRF), and National Science Foundation (No. NSF-CMMI-1400274). The autors also want to thank Ms. Donghua Han, and Mr. Boyang Ruan for their great help.
文摘Phosphorus has recently received extensive attention as a promising anode for lithium ion batteries (LIB ) due to its high theoretical capacity of 2,596