Ho改性的Mn-Ce/TiO_2催化剂低温脱硝性能的评价和表征（英文）

作为引起酸雨、光化学烟雾、雾霾等大气污染问题的主要根源,氮氧化物(NO_x)的防治已成为亟待解决的问题。选择性催化还原技术作为最成熟有效的脱硝技术,目前已经被广泛应用于各燃煤电厂.低温脱硝催化剂具有优秀的低温活性,使得脱硝装置可以安放在脱硫装置和除尘装置下游,受到了学者广泛的研究.目前低温脱硝催化剂的研究主要是对催化剂进行改性以提高催化剂的性能,已有许多研究报道了Sn、Ni、Co、Zr、Cr、Ni等对催化剂的改性影响.Ho作为一种改性元素被应用于光催化领域,能提高TiO_2的光催化能力.但Ho应用于脱硝领域的研究鲜有报道,其氧化物具有酸性位点有助于脱硝反应,因此研究Ho对低温SCR催化剂的改性作用具有重要意义.本文采用浸渍法制备Ho掺杂的Mn-Ce/TiO_2催化剂,研究了Ho的掺杂对于Mn-Ce/TiO_2催化剂低温脱硝性能的影响,同时还研究了烟气中的SO_2和H_2O对催化剂活性的影响,并利用XPS、XRD、H_2-TPR、NH_3-TPD等表征方法从物理性质和化学性质两方面对Ho改性的影响机理进行了研究.研究发现,Ho的掺杂能提高Mn-Ce/TiO_2催化剂的脱硝能力,有助于催化剂N_2选择性的提高.分析表明,Ho的掺杂有助于催化剂比表面积的提升,且能提高催化剂的酸性,有利于催化剂对NH_3的吸附,从而提高催化剂的性能.XPS表征结果表明Ho掺杂后的催化剂具有更高的化学吸附氧浓度和较高的Mn~(4+)/Mn~(3+)比例,使得脱硝反应更容易进行.改性后催化剂的抗水抗硫实验结果表明,Ho的掺杂能够提高催化剂的抗水抗硫性能.XRD结果表明,抗水抗硫实验后催化剂表面形成了硫酸铵盐,硫酸铵盐的形成会堵塞催化剂表面的活性位,限制脱硝反应的进行,从而影响催化剂的脱硝活性.同时,400℃下进行再生实验后的催化剂活性有所恢复,但是未能达到抗水抗硫实验前的活性,表明在抗水抗硫实验中催化剂表面形成了除硫酸铵盐以外的其他硫酸盐类.结合XPS和XRD表征结果,推断生成的盐类物质为硫酸锰和硫酸铈,从而导致再生后的催化剂的脱硝活性无法恢复到最初的活性水平.由此可以看出,硫酸盐的形成是催化剂在含硫气氛中失活的主要原因.     

Ho掺杂对Mn-Ce/TiO_2低温SCR催化剂的脱硝性能影响

采用浸渍法制备了五种掺杂不同比例的Ho的低温选择性催化还原(SCR)催化剂Mn0.4Ce0.07Hox/TiO_2。研究了Ho的引入对于Mn-Ce/TiO_2催化剂低温脱硝性能的影响,并采用XPS、XRF、BET、XRD、NH3-TPD等手段对催化剂的物理化学性质进行表征。结果表明,掺杂适量的Ho能够有效提高Mn-Ce/TiO_2催化剂的低温脱硝性能,当Ho/Ti掺杂比例为0.1时催化剂Mn0.4Ce0.07Ho0.1/TiO_2活性表现最佳,在200℃左右催化效率达到最高,为91.17%,在140-240℃催化效率达到80%以上。结果表明,Ho的掺杂能够增大催化剂的比表面积,提高催化剂化学吸附氧的浓度以及Ce的附着量。     

低温选择性催化还原脱硝Mn-Ce/TiO2催化剂的Pb中毒与再生研究

考察了Pb对Mn-Ce/TiO2低温选择性催化还原(SCR)脱硝活性的影响,并对Pb中毒的催化剂进行了再生;结合氮吸附、SEM、XRD、FT-IR、H2-TPR和NH3-TPD等表征结果,研究了Mn-Ce/TiO2催化剂Pb中毒和再生活性恢复的原因.结果表明,Pb对Mn-Ce/TiO2催化剂脱硝活性有明显的抑制作用;当...     

TiO_2载体掺杂对Mn-Ce/TiO_2催化剂低温脱硝性能影响研究

以TiO_2、TiO_2-Al_2O_3及TiO_2-SiO_2为载体,选取Mn为活性组分,Ce为活性助剂,采用分布共混法制备低温SCR催化剂,分析了TiO_2载体掺杂Al_2O_3、SiO_2改性后对Mn-Ce/TiO_2催化剂低温脱硝活性的影响,运用BET、SEM、XRD、H2-TPR以及NH_3-TPD等测试手段对催化剂进行了表征。结果表明,TiO_2载体经掺杂改性后,Mn-Ce/TiO_2催化剂的比表面积、孔结构参数以及表面孔结构形貌均得到改善和提高;Mn-Ce/TiO_2-Al_2O_3和Mn-Ce/TiO_2-SiO_2催化剂中TiO_2的结晶度均有不同程度降低;经TiO_2载体掺杂改性后的催化剂表面低温还原峰面积及催化剂表面酸性位种类及酸性大小显著改善,这都有助于提高催化剂的脱硝活性。通过对TiO_2载体掺杂SiO_2和Al_2O_3改性后,催化剂的脱硝活性明显提高,反应温度在80-140℃时,催化剂SCR脱硝活性的顺序是:Mn-Ce/TiO_2-SiO_2M n-Ce/TiO_2-Al_2O_3M n-Ce/TiO_2。     

元素掺杂提高低温选择性催化还原法催化剂抗水抗硫性研究

H2O和SO2是烟气中的固有成分,而低温选择性催化还原法（LT-SCR）催化剂易受烟气中H2O和SO2中毒。元素掺杂改性是最有效的提高SCR催化剂抗水、抗硫性方法之一。本文介绍了元素掺杂改性提高Mn基、V基、Ce基、Fe基等低温SCR催化剂抗水、抗硫性方法,以及理论计算在抗水、抗硫低温脱硝催化剂设计中的应用。研究结果为提高低温SCR催化剂抗水、抗硫性优化设计及构建提供理论基础。     

改性菱铁矿催化剂的催化脱硝活性及抗硫性研究

采用混合搅拌法制备了Ce、Zr掺杂改性的菱铁矿SCR脱硝催化剂,研究了Ce、Zr共同掺杂对催化剂催化脱硝性能及抗硫性的影响。结果表明,3%Ce+3%Zr掺杂菱铁矿催化剂(Ce_(0.03)/Zr_(0.03)-菱铁矿)具有优异的催化脱硝活性,在180-330℃,催化脱硝效率均在92%以上,该催化剂同时具有良好的抗SO_2性能,在210℃下通入体积分数为0.01%的SO_2,8 h后仍有95%以上的催化脱硝效率。通过XRF、BET、XRD、NH_3-TPD、TG等实验手段对催化剂成分、微观孔结构、晶相等进行表征。表征结果显示,Ce、Zr的掺杂能明显提高催化剂的比表面积以及表面结晶分散度,增强催化剂的表面酸性,促进硫酸铵盐在催化剂表面的分解。因此,催化剂具有优异的中低温催化脱硝活性及抗硫性。     

Mn/Ce改性菱铁矿催化剂在SCR脱硝反应中的特性研究（英文）

富含过渡元素的菱铁矿是用于制备选择性催化还原(SCR)脱硝催化剂的理想材料。在本研究中,对菱铁矿掺杂了Mn和Ce,并研究了Mn-Ce共掺杂改性菱铁矿在NH_3-SCR反应中去除NO_x的活性。结果表明,经过450℃煅烧后菱铁矿的主要成分FeCO_3能够转化为Fe_2O_3。菱铁矿掺杂Mn和Ce后能够提高比表面积和表面酸度,降低硫酸铵盐在催化剂表面上的热稳定性。因此,Mn-Ce共掺杂改性菱铁矿催化剂表现出较高的SCR脱硝活性和抗硫性。3%Mn1%Ce-菱铁矿催化剂在脱硝效率高于90%的温度窗口能够拓宽至180-300℃,同时在引入SO_2 7.5 h后该催化剂的脱硝效率仍高于75%。     

Mn/Ce改性菱铁矿催化剂在SCR脱硝反应中的特性研究

富含过渡元素的菱铁矿是用于制备选择性催化还原（SCR）脱硝催化剂的理想材料。在本研究中,对菱铁矿掺杂了Mn和Ce,并研究了Mn-Ce共掺杂改性菱铁矿在NH₃-SCR反应中去除NO_x的活性。结果表明,经过450℃煅烧后菱铁矿的主要成分FeCO₃能够转化为Fe₂O₃。菱铁矿掺杂Mn和Ce后能够提高比表面积和表面酸度,降低硫酸铵盐在催化剂表面上的热稳定性。因此,Mn-Ce共掺杂改性菱铁矿催化剂表现出较高的SCR脱硝活性和抗硫性。3% Mn1% Ce-菱铁矿催化剂在脱硝效率高于90%的温度窗口能够拓宽至180-300℃,同时在引入SO₂ 7.5 h后该催化剂的脱硝效率仍高于75%。     

水热法制备铁锰催化剂脱硝性能及抗水抗硫性能研究

采用水热法制备了MnO_x-FeO_y催化剂,在固定床模拟燃煤烟气气氛下考察其脱硝活性,并研究催化剂的抗水抗硫性能;采用XRD、BET、TEM、TG、XPS和H2-TPR技术对催化剂进行了表征.结果表明,一步水热法制备的MnO_x-FeO_y(Fe/(Fe+Mn)=0.5)催化剂,在80℃时NO_x脱除率为90%,120℃脱硝效率达到99%.表征发现一步水热法合成的催化剂Mn和Fe之间存在较强的相互作用,Fe的掺杂可降低锰的起始还原温度,促进低温NH_3-SCR反应.且其较大的比表面积以及较低的晶化程度使其具有较高的催化NO_x活性.采用液相沉积-两步水热法制备的催化剂Fe/(Fe+Mn)=0.5HT在温度区间为150~250℃内,NO_x脱除效率达到98%以上,同时该催化剂表现出较优的抗水抗硫性能,10%H_2O和0.6%SO_2同时作用8 h,NO转化率仍维持在73%左右,优于一步水热法合成的催化剂,且经500℃活化再生后,催化剂活性可基本恢复.这可能是由于Fe/(Fe+Mn)=0.5HT催化剂中,FeO_y分散在MnO_x表面,减少了硫酸铵盐和硫酸锰的沉积,提高了催化剂抗硫抗水性能.     

SO_2和H_2O对CeO_2/TiO_2/堇青石催化剂选择催化还原NO_x性能的影响

采用浸渍法制备了以堇青石为基底、氧化铈为活性组分的整体式脱硝催化剂CeO2/TiO2/堇青石催化剂。通过与商业钒基催化剂(V2O5-WO3/TiO2/堇青石)的对比研究发现,CeO2/TiO2/堇青石催化剂表现出了优良的抗硫抗水性能,经过30 h抗硫抗水实验,CeO2/TiO2/堇青石催化剂的氮氧化物转化率仍能保持在70%以上,仅下降了5%。BET、XRD、FT-IR和TG表征结果表明,在含硫含水气氛中反应时,CeO2/TiO2/堇青石和V2O5-WO3/TiO2/堇青石催化剂表面均有硫酸铵盐的生成,且前者的生成量明显低于后者。NH3-DRIFT分析结果表明,在含硫含水气氛中两种催化剂表面Brnsted酸性都被增强,而Lewis酸性有所减弱。进一步的XPS分析结果表明,烟气中的SO2+H2O会使催化剂表面Ce4+向Ce3+发生转化,从而导致化学吸附氧含量增加,这是CeO2/TiO2/堇青石催化剂具有优良抗硫抗水性能的重要原因。     

Synthesis of novel MnOx@TiO2 core-shell nanorod catalyst for low-temperature NH3-selective catalytic reduction of NOx with enhanced SO2 tolerance

In this study, a MnO_x@TiO₂ core-shell catalyst prepared by a two-step method was used for the low-temperature selective catalytic reduction of NO_x with NH₃. The catalyst exhibits high activity, high stability, and excellent N₂ selectivity. Furthermore, it displays better SO₂ and H₂O tolerance than its MnO_x, TiO₂, and MnO_x/TiO₂ counterparts. The prepared catalyst was characterized systematically by transmission electron microscopy, high-resolution transmission electron microscopy, X-ray diffraction, Raman, BET, X-ray photoelectron spectroscopy, NH₃ temperature-programmed desorption and H₂ temperature-programmed reduction analyses. The optimized MnO_x@TiO₂ catalyst exhibits an obvious core-shell structure, where the TiO₂ shell is evenly distributed over the MnO_x nanorod core. The catalyst also presents abundant mesopores, Lewis-acid sites, and high redox capability, all of which enhance its catalytic performance. According to the XPS results, the decrease in the number of Mn⁴⁺ active centers after SO₂ poisoning is significantly lower in MnO_x@TiO₂ than in MnO_x/TiO₂. The core-shell structure is hence able to protect the catalytic active sites from H₂O and SO₂ poisoning.     

One-step synthesized SO42–-TiO2 with exposed (001) facets and its application in selective catalytic reduction of NO by NH3

A sample of sulfated anatase TiO₂ with high-energy (001) facets (TiO₂-001) was prepared by a simple one-step hydrothermal route using SO₄^2– as a morphology-controlling agent. After doping ceria, Ce/TiO₂-001 was used as the catalyst for selective catalytic reduction (SCR) of NO with NH₃. Compared with Ce/P25 (Degussa P25 TiO₂) and Ce/P25-S (sulfated P25) catalysts, Ce/TiO₂-001 was more suitable for medium- and high-temperature SCR of NO due to the high surface area, sulfation, and the excellent properties of the active-energy (001) facets. All of these facilitated the generation of abundant acidity, chemisorbed oxygen, and activated NO_x-adsorption species, which were the important factors for the SCR reaction.     

Mechanistic study of Ce-modified MnO<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript>/TiO<Subscript>2</Subscript> catalysts with high NH<Subscript>3</Subscript>-SCR performance and SO<Subscript>2</Subscript> resistance at low temperatures

A series of Ce–MnO _x /TiO₂ catalysts were prepared using a novel sol–gel template method and investigated for low-temperature selective catalytic reduction (SCR) of NO with NH₃ at temperatures ranging from 353 to 473 K. The 0.07Ce–MnO _x /TiO₂ catalyst showed the highest activity and best resistance to SO₂ poisoning. The structure and properties of the catalysts were characterized using X-ray diffraction (XRD) analysis, thermogravimetric analysis (TGA), thermogravimetry (TG)–differential scanning calorimetry (DSC)–mass spectroscopy (MS), high-resolution transmission electron microscopy (HRTEM), Brunauer–Emmett–Teller (BET) measurements, H₂-temperature-programmed reduction (TPR), and NH₃-temperature-programmed desorption (TPD). The superior catalytic activity of the 0.07Ce–MnO _x /TiO₂ catalyst was probably due to a change in the active components, an increase in surface active oxygen and surface acid sites, and lower crystallinity and larger surface area with Ce doping. Furthermore, the reduction ability also became stronger. The SO₂ poisoning resistance of the 0.07Ce–MnO _x /TiO₂ catalyst improved because doping with Ce can effectively decrease the formation of ammonium salt on the catalyst surface and the sulfation of MnO _x . In situ diffuse-reflectance infrared Fourier-transform (DRIFT) spectroscopy experiments indicated that addition of Ce could promote adsorption of NH₃ and inhibit generation of some nitryl species. The SCR reactions over the catalysts mainly followed the Eley–Rideal mechanism accompanied with a partial Langmuir–Hinshelwood mechanism.     

Promotional effect of Ce on the SCR of NO with NH<Subscript>3</Subscript> at low temperature over MnO<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript> supported by nitric acid-modified activated carbon

Different amounts of Mn and Ce oxides were loaded onto nitric acid-modified activated carbon (ACN) by wet impregnation. The series of catalysts were employed for the selective catalytic reduction of NO _x by NH₃ at temperatures between 100 and 250 °C. Cerium-modified catalysts exhibited higher de-NO _x performance than those modified with Mn/ACN, even with the same total loadings. The precursor solution with a molar ratio for Ce/(Mn + Ce) of 0.4 exhibited the highest catalytic activity. Enhanced resistance to SO₂ and H₂O and better stability were observed for 10%Mn–Ce(0.4)/ACN relative to 10%Mn/ACN. The catalysts were further characterized by N₂ physisorption, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), hydrogen temperature-programmed reduction (H₂-TPR), and temperature-programmed desorption of ammonia (NH₃-TPD). The N₂ physisorption and XRD results suggested that co-doping Ce with Mn increased the surface area and promoted the dispersion of Mn–Ce binary metal oxides. H₂-TPR the NH₃-TPD results demonstrated that the interaction between manganese oxide and cerium oxide species enhanced the redox and surface acidity of 10%Mn–Ce(0.4)/ACN.     

Effect of SO<Subscript>2</Subscript> on SCR activity of MnOx/PG catalysts at low temperature

Palygorskite (PG)-supported manganese oxide catalysts (MnOx/PG) were prepared for the selective catalytic reduction (SCR) of NO with ammonia in the presence of SO₂ at low temperature. The influence of gaseous SO₂ on the performance of the catalyst was studied by means of specific surface area (Brunauer-Emmett-Teller, BET) analysis, scanning electron microscopy (SEM), thermogravimetric (TG) analysis, temperature-programmed desorption (TPD) and X-ray photoelectron spectroscopy (XPS). The results showed that the SCR activity of Mn10/PG was significantly inhibited by gaseous SO₂ at temperatures below 300°C. However, the SCR activity of Mn10/PG was markedly promoted by SO₂ in a higher temperature range of 300°C to 500°C. The sulphating of surface active species (MnOx) was suggested to inhibit the oxidation of NH₃ to NO leading to enhancement of the SCR activity at a higher temperature range of 300°C to 500°C and decrease in the SCR activity at temperatures below 300°C.     

Comparative study of Co/TiO<Subscript>2</Subscript>, Co–Mn/TiO<Subscript>2</Subscript> and Co–Mn/Ti–Ce catalysts for oxidation of elemental mercury in flue gas

The Co–Mn/Ti–Ce catalyst prepared by sol–gel and impregnation method was evaluated for catalytic oxidation of Hg⁰ in the simulated flue gas compared with Co/TiO₂ and Co–Mn/TiO₂. The results showed that Co–Mn/Ti–Ce catalyst exhibited higher catalytic activity (around 93% Hg⁰ removal efficiency in the temperature of 150 °C with 6% O₂, 400 ppm NO, 200 ppm SO₂ and 3% H₂O) than Co/TiO₂ and Co–Mn/TiO₂. Based on the characterization results of N₂ adsorption–desorption, XRD, UV–Vis, XPS, H₂-TPR and Hg-TPD, it could be concluded that the lower band gap, better reducibility and mercury adsorption capability and the presence of Co³⁺/Co²⁺, Mn⁴⁺/Mn³⁺ and Ce⁴⁺/Ce³⁺ redox couples as well as surface oxygen species contributed to the excellent Hg⁰ oxidation removal performance. In addition, well dispersion of active components and a synergetic effect among Co, Mn and Ce species might improve the activity further. A Mars–Maessen mechanism is thought to be involved in the Hg⁰ oxidation. The lattice oxygen derived from MnO _x or CoO _x would react with adsorbed Hg⁰ to form HgO and the consumption of lattice oxygen could be replenished by O₂. For Co–Mn/Ti–Ce, MnO _x?1 could be alternatively reoxidized by the lattice oxygen derived from adjacent CoO _x and CeO _x which is beneficial to the Hg⁰ oxidation.     

Ho改性Fe-Mn/TiO_2低温SCR脱硝催化剂硫中毒及热还原再生研究

以Ho改性Fe-Mn/TiO_2低温SCR脱硝催化剂为研究对象,通过活性评价和一系列表征技术对其低温抗硫性能和催化剂的热还原再生进行研究。结果表明,硫酸铵((NH_4)_2SO_4)在催化剂表面的沉积以及活性组分硫酸化(MnSO_4)是催化剂硫中毒的主要原因。当烟气中的SO_2体积分数低于0.04%时,Fe_(0.3)Ho_(0.1)Mn_(0.4)/TiO_2催化剂呈现出良好的抗硫性。在此条件下,当切断SO_2的供应时催化剂的脱硝活性可获得显著恢复。当通入的SO_2体积分数增加至0.1%时,催化剂会发生不可逆失活。在体积分数5%NH_3气氛下,失活催化剂经过350℃的热还原再生处理60 min后,其微观结构和理化性质能够得到明显恢复,且NO_x转化率可以回升至80%左右。     

Chemical deactivation of Cu-SAPO-18 deNOx catalyst caused by basic inorganic contaminants in diesel exhaust

Contaminants (K, Na, Ca, and Mg) were introduced into Cu-SAPO-18 via incipient wetness impregnation to investigate their effect on the selective catalytic reduction of NO_x with NH₃ (NH₃-SCR) over Cu-SAPO-18. After the introduction of contaminants into Cu-SAPO-18, the quantity of acidic sites and Cu²⁺ species in catalyst decreases owing to the replacement of H⁺ and Cu²⁺ by K⁺, Na⁺, Ca²⁺, and Mg²⁺. Furthermore, the loss of isolated Cu^{2+ induces the generation of CuO and CuAl₂O₄-like phases, which causes further loss in the Brunauer-Emmett-Teller surface area of the catalyst. Consequently, the deNO_x performance of the contaminated Cu-SAPO-18 catalysts drops. Such decline in NH₃-SCR performance becomes more pronounced by increasing the contaminant contents from 0.5 to 1.0 mmol/g_catal. In addition, the deactivation influence of the contaminants on Cu-SAPO-18 is presented in the order of K> Na > Ca > Mg, which is consistent with the order of reduction of acidic sites. To a certain degree, the effect of the acidic sites on the deactivation of Cu-SAPO-18 might be more significant than that of isolated Cu2+ and the catalyst framework. Moreover, kinetic analysis of NH₃-SCR was conducted, and the results indicate that there is no influence of contaminants on the NH₃-SCR mechanism.}     

Study of Fe-doped V<Subscript>2</Subscript>O<Subscript>5</Subscript>/TiO<Subscript>2</Subscript> catalyst for an enhanced NH<Subscript>3</Subscript>-SCR in diesel exhaust aftertreatment

Selective catalytic reduction (SCR) with ammonia has been considered as the most promising technology, as its effect deals with the NO_X. Novel Fe-doped V₂O₅/TiO₂ catalysts were prepared by sol–gel and impregnation methods. The effects of iron content and reaction temperature on the catalyst SCR reaction activity were explored by a test device, the results of which revealed that catalysts could exhibit the best catalytic activity when the iron mass ratio was 0.05%. It further proved that the VTiFe (0.05%) catalyst performed the best in denitration and its NO_X conversion reached 99.5% at 270 °C. The outcome of experimental procedures: Brunauer–Emmett–Teller surface area, X-ray powder diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, temperature-programmed reduction and adsorption (H₂-TPR, NH₃-TPD) techniques showed that the iron existed in the form of Fe³⁺ and Fe²⁺ and the superior catalytic performance was attributed to the highly dispersed active species, lots of surface acid sites and absorbed oxygen. The modified Fe-doped catalysts do not only have terrific SCR activities, but also a rather broad range of active temperature which also enhances the resistance to SO₂ and H₂O.     

Mn负载量对nMnO_x/TiO_2催化剂NH_3-SCR催化性能的影响

MnO_x/TiO_2催化剂由于具有优异的低温脱硝性能,已成为SCR催化剂的研究热点之一.我们通过浸渍法制备了一系列不同Mn负载量的nMnO_x/TiO_2(n=2.5%, 5%, 10%, 15%)(质量分数)催化剂,考察Mn负载量对催化剂脱硝性能的影响.利用N_2物理吸附, X-Ray Diffraction (XRD), Scanning Electron Microscope(SEM),Temperature Programmed Reduction with H_2(H_2-TPR),Temperature Programmed Desorption with NH_3(NH_3-TPD)和X-Ray Photoelectron Spectroscopy (XPS)对其结构进行表征.结果表明,催化剂的脱硝性能随着Mn负载量(2.5%～15%)(质量分数)的变化呈现"火山型"曲线,当Mn负载量为10%(质量分数)时,催化剂的脱硝性能最佳. H_2-TPR和XPS结果表明nMnO_x/TiO_2催化剂上表面氧比例和表面Mn~(4+)浓度均随着Mn负载量的增大,先增大后减小,具体顺序为10MnO_x/TiO_(2 ) 15MnO_x/TiO_(2 )5MnO_x/TiO_(2 ) 2.5MnO_x/TiO_2,与脱硝性能顺序完全一致.进一步关联表面氧的比例与T_(50)发现,催化剂的表面氧的比例与T_(50)呈线性关系,即表面氧比例越高, T_(50)越小,脱硝活性越高. NH_3-TPD结果表明,弱酸酸量的增加有助于低温脱硝活性的提高.这些结果揭示了Mn负载量影响脱硝性能的作用规律,为今后开发高效的锰基低温脱硝催化剂提供了技术支撑.