2,6-Diacetylpyridinesalicylaldazine complexes of bivalent metal ions

Summary 2,6-Diacetylpyridinesalicylaldazine (H₂daps) forms complexes [Ni(H₂daps)ClH₂O]Cl, [M(H₂daps)Cl₂H₂O] (M = Mn, Co, Cu or Zn) and [M(daps)(H₂O)₂] (M = Mn, Co, Ni, Cu or Zn) which have been characterized by elemental analyses, physicochemical methods, spectroscopy and X-ray powder diffraction.     

Synthesis, characterization and antiproliferative activity of transition metal complexes with 3-(4,5-diphenyl-1,3-oxazol-2-yl)propanoic acid (oxaprozin)

A series of novel Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) complexes with oxaprozin (Hoxa), a non-steroidal anti-inflammatory drug, has been synthesized. The drug and complexes have been characterized by elemental and thermogravimetric (TG) analysis, Fourier transform (FT)-IR, 1H-NMR, 13C-NMR, UV-Vis spectroscopy and magnetic susceptibility measurements. The (pseudo)octahedral geometry has been proposed for all complexes based on electronic spectra and magnetic moments. With exception of the Cu(II) complex, where bridging bidentate mode of COO groups has been found, FT-IR spectra confirmed chelately coordinated COO groups in the other complexes. The general formula of the complexes is [M(H2O)2(oxa)2 ·χH2O, with χ=2 for M=Mn, Co and Ni and χ=1.5 for Zn. The binuclear Cu(II) complex, [Cu2(H2O)2(OH)(oxa)3]·2H2O, has strong Cu-Cu interactions of antiferromagnetic type. The complexes and Hoxa did not exhibit the cytotoxic effect to peritoneal macrophages. For the first time these complexes have been tested for their in vitro antiproliferative activity against human colon and breast cancer cell lines, HCT-116 and MDA-231, respectively. For all investigated compounds significant antiproliferative effects have been observed. Ni(II) complex has been shown to be a promising antiproliferative agent exerting excellent activity against HCT-116 even in nanomolar concentrations.     

Triangular trinuclear metal-N4 complexes with high electrocatalytic activity for oxygen reduction

A new class of macrocyclic metal-N(4) complexes [MN(4)](n) (M = Co and Fe) were designed and synthesized based on a triangular ligand. Their unique triangular trinuclear structure provides a high density of active sites and facilitates the reduction of dioxygen via a four-electron pathway. Among them, a [CoN(4)](3)/C catalyst (20 wt %) exhibits high catalytic activity and long-time stability for the oxygen reduction reaction (ORR) in alkaline conditions, superior to the commercial Pt/C catalyst. Such structurally well-defined [MN(4)](n) complexes provide a platform for a new generation of nonprecious metal catalysts (NPMCs) for fuel cell applications.     

Electrocatalytic activity of carbon-supported metallophthalocyanine catalysts toward oxygen reduction reaction in alkaline solution

Carbon-supported metallophthalocyanine catalysts, composed of a transition central metal M (M = Co, Mn, Ni, Fe) in the phthalocyanine ring, were synthesized in this work. As cathodic reaction in a fuel cell, the oxygen reduction reaction (ORR) was investigated in alkaline medium with linear scanning voltammetry at the surface of these electrocatalysts deposited onto a rotating disk electrode (RDE). It was found that the number of electrons transferred depended on the nature of the metallic cation in the catalyst. Evidences provided with Koutecky-Levich approach showed that iron phthalocyanine (FePc) exhibited the better electrocatalytic ability toward the ORR with four electrons exchanged and low activation overpotential. Among these different as-prepared materials, MnPc and FePc led to a four-electron pathway, while CoPc and NiPc proceeded by a two-electron route. The latter reaction process was also determined with a rotating ring-disk electrode (RRDE), which allowed the determination of hydrogen peroxide formed as O₂ reduction intermediate in a small amount, i.e., less than 1.2 %.     

Co3O4/聚吡咯/石墨烯碱性溶液中电化学还原氧

燃料电池具有较高的能量密度和发电效率,以清洁能源为原料,零污染排放,是一种具有发展前景的能量储存和转化装置.阴极氧还原反应(ORR)在燃料电池中起着关键作用.ORR广泛采用贵金属铂基催化剂,但是它们价格昂贵,电子动力学转移速率慢,碱性条件下易团聚,这些亟需解决的问题阻碍了燃料电池商业化进程.近期,一些非贵金属催化剂被广泛研究,例如氮掺杂碳材料、Fe/N/C和Co/N/C材料等,它们有可能在未来替代铂基催化剂.我们的目标是合成新型高催化活性的Co/N/C及其衍生非贵金属材料,用于ORR催化反应.由于石墨烯具有独特的形貌、较大的比表面积和良好的导电性,其表面含有功能化的官能团,所以我们选择石墨烯作为碳载体.首先,用改性休克尔方法合成了氧化石墨烯(GO),为了提高其催化活性,采用聚吡咯作为氮源对其进行了氮掺杂,制备了聚吡咯/氧化石墨烯(Ppy/GO).通过ORR催化性能测试发现,GO对ORR具有一定的催化活性,它的起始电位和阴极电流电位分别为–0.31 V vs SCE和–0.38 V vs SCE;Ppy/GO的起始电位和阴极电流电位分别为–0.20 V vs SCE和–0.38 V vs SCE,氮掺杂对GO的催化活性有所提高.采用水热法沉积氧化钴合成了Co3O4/聚吡咯/氧化石墨烯(Co3O4/Ppy/GO).其形貌为Co3O4分散在氮掺杂GO表面.在KOH电解质(0.1 mol/L)中测试,Co3O4/Ppy/GO的起始电位和阴极电流电位分别为–0.20 V和–0.38 V vs SCE.经过800℃高温煅烧处理后,Co3O4/Ppy/GO-800的催化活性明显提高,起始电位和阴极电流电位分别达到–0.10 V和–0.18 V vs SCE.ORR电子转移数为3.4,接近于4电子反应途径.Co3O4/Ppy/GO对ORR的催化活性及4电子催化选择性较高,可能是由于纳米形态的Co3O4和Ppy/GO之间具有较强的表面作用力,聚吡咯掺杂的氧化石墨烯具有较强的电子储存及释放能力.综上,我们通过水热法制备了钴、氮共掺杂的GO,并研究了其对ORR的催化活性和电子转移选择性.结果表明Co3O4/Ppy/GO是一种高效的非贵金属电催化剂,在碱性电解质中具有很高的ORR催化活性,在燃料电池阴极催化剂方面很有前景.     

Synthesis, spectroscopy, and characterization of some bis-nicotinamide metal(II) dihalide complexes

We report synthesis of six new bis-nicotinamide metal(II) dihalide complexes [M(nia)(2)Cl(2); M = Mn, Co; nia:nicotinamide, M(nia)(2)Br(2); M = Mn, Hg; M(nia)(2)I(2); M = Cd, Cu], and their characterization by combining infrared spectroscopy with density functional theory (DFT) calculations. Infrared spectra indicate that ring-nitrogen is the active donor cite, and the atomic structure of the complexes is determined to be polymeric octahedral or distorted polymeric octahedral. Spin polarized electronic ground state is obtained for Mn, Co, and Cu halide complexes. The colors of the complexes also support the conclusion of octahedral coordination around the metal atoms, in agreement with DFT results.     

Spectral, magnetic and biological studies of 1,4-dibenzoyl-3-thiosemicarbazide complexes with some first row transition metal ions

The ligand 1,4-dibenzoyl-3-thiosemicarbazide (DBtsc) forms complexes [M(DBtsc-H)(SCN)] [M = Mn(II), Co(II) or Zn(II)], [M(DBtsc-H) (SCN)(H₂O)] [M = Ni(II) or Cu(II)], [M(DBtsc-H)Cl] [M = Co(II), Ni(II), Cu(II) or Zn(II)] and [Mn(DBtsc)Cl₂], which have been characterized by elemental analyses, magnetic susceptibility measurements, UV/Vis, IR,¹H and¹³C NMR and FAB mass spectral data. Room temperature ESR spectra of the Mn(II) and Cu(II) complexes yield <g> values, characteristic of tetrahedral and square planar complexes respectively. DBtsc and its soluble complexes have been screened against several bacteria, fungi and tumour cell lines.     

Co-M(M=La,Ce, Fe,Mn, Cu,Cr)复合金属氧化物催化分解N2O

通过共沉淀法制备了一系列Co-M(M= La, Ce, Fe, Mn, Cu, Cr)复合金属氧化物及纯Co3O4催化剂, 考察了其催化分解N2O 的活性. 结果表明在研究的系列催化剂中, Co-Ce 复合氧化物催化剂具有最好的催化分解N2O的活性; 其活性与Ce/Co 摩尔比有直接的关系, 当Ce/Co 摩尔比为0.05 时(CoCe0.05 催化剂)催化活性最佳; 当有NO 和O2共存时, 可能在催化剂活性中心上形成表面硝酸盐或亚硝酸盐吸附物种而使其活性受到较大影响. 通过对Co-M 催化剂的XRD、BET、O2-TPD及H2-TPR 等表征结果的分析, 发现作为主要活性位的Co2+的氧化还原能力是影响催化剂活性的主要原因. 这是因为根据反应机理, N2O 的表面分解步骤与Co2+氧化成Co3+的能力相关, 而吸附氧的脱附与Co3+还原成Co2+的能力相关. 在所研究的催化剂中, 添加除CeO2之外的其它过渡金属氧化物时, 催化剂中Co3+/Co2+的氧化还原能力降低, 因此其催化性能降低. 另外, 添加不同过渡金属氧化物也改变了N2O 催化分解反应的速控步骤.     

Cobalt(III) corroles as electrocatalysts for the reduction of dioxygen: reactivity of a monocorrole, biscorroles, and porphyrin-corrole dyads

Three series of cobalt(III) corroles were tested as catalysts for the electroreduction of dioxygen to water. One was a simple monocorrole represented as (Me(4)Ph(5)Cor)Co, one a face-to-face biscorrole linked by an anthracene (A), biphenylene (B), 9,9-dimethylxanthene (X), dibenzofuran (O) or dibenzothiophene (S) bridge, (BCY)Co(2) (with Y = A, B, X, O or S), and one a face-to-face bismacrocyclic complex, (PCY)Co(2), containing a Co(II) porphyrin and a Co(III) corrole also linked by one of the above rigid spacers (Y = A, B, X, or O). Cyclic voltammetry and rotating ring-disk electrode voltammetry were both used to examine the catalytic activity of the cobalt complexes in acid media. The mixed valent Co(II)/Co(III) complexes, (PCY)Co(2), and the biscorrole complexes, (BCY)Co(2), which contain two Co(III) ions in their air-stable forms, all provide a direct four-electron pathway for the reduction of O(2) to H(2)O in aqueous acidic electrolyte when adsorbed on a graphite electrode, with the most efficient process being observed in the case of the complexes having an anthracene spacer. A relatively small amount of hydrogen peroxide was detected at the ring electrode in the vicinity of E(1/2) which was located at 0.47 V vs SCE for (PCA)Co(2) and 0.39 V vs SCE for (BCA)Co(2). The cobalt(III) monocorrole (Me(4)Ph(5)Cor)Co also catalyzes the electroreduction of dioxygen at E(1/2) = 0.38 V with the final products being an approximate 50% mixture of H(2)O(2) and H(2)O.     

过渡金属（Cu，Fe，Mn，Co）改性高分散V2O5/TiO2作为高效NH3-SCR脱硝催化剂

选择性催化还原(SCR)是目前固定源及移动源中控制NOx排放最为有效的技术手段之一.工业上应用最广泛的商业SCR催化剂是钒基催化剂.钒基催化剂经钨(钼)改性后具有较好的活性、稳定性和抗水抗硫性能,但在应用过程中仍存在N2选择性较低、活性温度窗口(300–400 oC)较窄及高温下V2O5极易流失等不足,且钨(钼)的价格十分昂贵.因此,用廉价组分提高钒基催化剂的催化性能在实际工业应用中仍具有重要意义.研究发现,很多非贵金属(如Cu, Fe, Mn, Co, Ce, Zr, Nb, Sn, La等)都可以代替钨(钼)用来提高钒基催化剂的选择性、活性温度窗口和(热)稳定性能等.引入的金属通常以氧化物或钒酸盐形式存在,并与活性组分钒物种有很强的相互作用,从而提高钒物种的氧化还原性能及分散度,同时增大表面酸性位数量,抑制锐钛矿向金红石相转变.近年来很多研究发现,经金属改性的钒基催化剂以钒酸盐形式存在时可有效提高催化剂活性和 N2选择性,尤其可显著提高催化剂的(热)稳定性.本文采用浸渍法以廉价易得、储量丰富的过渡金属改性钒基催化剂,得到高度分散的M-V/TiO2(M = Cu, Fe, Mn, Co)脱硝催化剂.结果发现, Cu-V/TiO2和Fe-V/TiO2催化剂表现出较好的催化活性和N2选择性以及优异的稳定性和抗H2O/SO2性能,其中Cu-V/TiO2的工作温度窗口扩展到225–375oC. X射线衍射、拉曼光谱和EDX-mapping表征结果证明,钒物种及引入的金属高度分散在TiO2载体表面,并生成了钒酸盐.氢气程序升温还原结果表明,钒酸盐的形成导致钒物种的还原峰向低温区移动,有利于催化剂氧化还原性能的提升. X射线光电子能谱结果表明, Cu-V/TiO2催化剂表面具有更多的活性氧物种(Oα),且具有较强的电子间相互作用,是SCR活性提高的关键原因之一. NH3程序升温脱附和原位红外光谱实验结果表明,金属的引入可以提高酸量和酸强度; Cu-V/TiO2催化剂表面主要为Lewis酸性位,而Fe-V/TiO2催化剂表面主要为Br?nsted酸性位,两者可能导致不同的SCR反应机理,但均可以提高催化剂在高温下的N2选择性.综上所述,过渡金属改性的钒基催化剂中Cu-V/TiO2具有最好的活性和N2选择性以及较强的稳定性和抗H2O/SO2性能,可能得益于其表面更多的活性氧物种和更多更强的酸性位.     

Mn_xCo_(2.5-x)Al_(0.5)O_4尖晶石型三元复合氧化物催化分解N_2O(英文)

用溶胶凝胶法制备了一组Mn_xCo_(2.5-x)Al_(0.5)O_4尖晶石型三元复合氧化物,用于有氧气氛下的N_2O催化分解反应.用N_2物理吸附、X射线衍射(XRD)、扫描电镜(SEM)、H_2程序升温还原(H_2-TPR)、O_2程序升温脱附(O_2-TPD)、X射线光电子能谱(XPS)等技术对催化剂进行了结构表征,考察了催化剂组成、母液pH、K负载量等制备参数对其催化活性的影响.结果表明:K的加入弱化了催化剂表面的金属-氧化学键,有利于表面氧物种的脱除,改性催化剂有较高的催化活性和抗水性,其中母液pH=2、K/(Mn+Co)比为0.02的K/Mn_(0.2)Co_(2.3)Al_(0. 5)O_4催化剂活性较高,该催化剂在有氧、有氧有水气氛400℃连续反应50 h,N_2O转化率分别达98.5%和76.5%.     

Structural studies of metal complexes containing amide ligands

Complexes of Mn(II), Fe(II), Co(II), Ni(II), Cu(II) and Pd(II) with di-N-phenyl pyromellitic diimide (PhPMDI) and di-N-pyridyl pyromellitic diimide (PyPMDI) were prepared and characterized based on analytical, molar conductance, magnetic, IR, PMR, electronic and ESR data. Based on analytical and molar conductance, the complexes have been formulated as [M(PhPMDA)(H₂O)₂]_n (M = Mn, Fe, Co, Ni), [Cu(PhPMDA)]_n [Pd₂(PhPMDA)Cl₂(H₂O)₂], [M(PyPMDA)]_n (M = Mn, Fe, Co, Ni and Cu) and [Pd₂(PyPMDA)Cl₂] In all these complexes PhPMDA acts as a mononegative bidentate ligand whereas PyPMDA acts as a mononegative tridentate one in the form of amide rather than imide. The geometries of the complexes have been proposed based on the electronic spectra. The various bonding parameters have been calculated from the ESR spectra of Cu(II) complexes.     

Formation of 1 D and 3 D coordination polymers in the solid state induced by mechanochemical and annealing treatments: bis(3-cyano-pentane-2,4-dionato) metal complexes

Bis(3-cyano-pentane-2,4-dionato) (CNacac) metal complex, [M(CNacac)(2)], which acts as both a metal-ion-like and a ligand-like building unit, forms supramolecular structures by self-assembly. Co-grinding of the metal acetates of Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) with CNacacH formed a CNacac complex in all cases: mononuclear complex was formed in the cases of Mn(II), Cu(II) and Zn(II), whereas polymeric ones were formed in the cases of Fe(II), Co(II) and Ni(II). Subsequent annealing converted the mononuclear complexes of Mn(II), Cu(II) and Zn(II) to their corresponding polymers as a result of dehydration of the mononuclear complexes. The resultant Mn(II), Fe(II), Co(II), Ni(II) and Zn(II) polymeric complexes had a common 3 D structure with high thermal stability. In the case of Cu(II), a 1 D polymer was obtained. The Mn(II), Cu(II) and Zn(II) polymeric complexes returned to their original mononuclear complexes on exposure to water vapour but they reverted to the polymeric complexes by re-annealing. Co-grinding of metal chlorides with CNacacH and annealing of the mononuclear CNacac complexes prepared from solution reactions were also examined for comparison. [Mn(CNacac)(2)(H(2)O)(2)], [M(CNacac)(2)(H(2)O)] (M=Cu(II) and Zn(II)) and [M(CNacac)(2)](infinity) (M=Mn(II), Fe(II) and Zn(II)) are new compounds, which clearly indicated the power of the combined mechanochemical/annealing method for the synthesis of varied metal coordination complexes.     

Bisphosphonate metal complexes as selective inhibitors of Trypanosoma cruzi farnesyl diphosphate synthase

In the search for a pharmacological answer to treat Chagas disease, eight metal complexes with two bioactive bisphosphonates, alendronate (Ale) and pamidronate (Pam), were described. Complexes of the formula [M(2)(II)(Ale)(4)(H(2)O)(2)]·2H(2)O, with M = Cu, Co, Mn, Ni, and ([CuPam]·H(2)O)(n) as well as [M(II)(Pam)(2)(H(2)O)(2)]·3H(2)O, with M = Co, Mn and Ni, were synthesized and fully characterized. Crystal structure of [Cu(2)(II)(Ale)(4)(H(2)O)(2)]·2H(2)O, [Co(II)(Pam)(2)(H(2)O)(2)] and [Ni(II)(Pam)(2)(H(2)O)(2)] were solved by X-ray single crystal diffraction methods and the structures of [M(2)(II)(Ale)(4)(H(2)O)(2)]·2H(2)O complexes M = Co, Mn and Ni were studied by X-ray powder diffraction methods. All obtained complexes were active against the amastigote form of Trypanosoma cruzi (T. cruzi), etiological agent of Chagas disease. Most of them were more active than the corresponding free ligands showing no toxicity for mammalian cells. The main mechanism of the antiparasitic action of bisphosphonates, inhibition of parasitic farnesyl diphosphate synthase (TcFPPS), remains in the obtained metal complexes and an increase in the inhibiting enzyme levels was observed upon coordination. Observed enzymatic inhibition was selective for TcFPPS as the metal complexes showed no or little inhibition of human FPPS. Additionally, metal complexation might improve the bioavailability of the complexes through the hindrance of the phosphonate group's ionization at physiological pH and, eventually, through the ability of plasma proteins to work as complex transporters.     

Synthesis,structure and infrared spectral studies of some new metal (II) complexes of 3-phenyl-4-acetyl-5-isoxazolone (HPAI)

The divalent metal complexes of Mn, Co, Ni, Cu, Zn, Mg, Cd and Pb with 3-phenyl-4-acetyl-5-isoxazolone (HPAI) have been prepared for the first time. The complexes were characterized by utilising elemental analysis, conductivity measurements, i.r. and proton NMR spectroscopy. It has been shown that HPAI behaves as a bidentate ligand forming neutral metal chelates through the carbonyl and hydroxyl groups of the enolic form. The MO stretching frequencies for the transition metals show good agreement with the Irwing—Williams stability order Cu ⪢ Ni ⪢ Co ⪢ Zn ⪢ Mn.     

Coordination polymers with end-on azido and pyridine carboxylate N-oxide bridges displaying long-range magnetic ordering with low dimensional character

A series of 2D and one 3D transition-metal-azido coordination polymers with pyridine carboxylate N-oxide, isonicotinate N-oxide (INO), and nicotinate N-oxide (NNO) as the coligands were synthesized by a hydrothermal method and structurally and magnetically characterized. These complexes have the formulas [M(L)(N3)(H2O)]n (L = INO and M = Mn, 1.Mn; Co, 2.Co; Ni, 3.Ni and L = NNO and M = Mn, 4.Mn; Co, 5.Co; Ni, 6.Ni) and [Cu(L)(N3)(H2O)(0.5)]n (L = INO, 7.Cu; NNO, 8.Cu). All complexes consist of end-on azido and syn-syn carboxylato mixed-bridged M-N(3)/COO chains that are further linked by the pyridine N-oxide group of the INO or NNO to give rise to 2D layered structures for 1.Mn, 2.Co, 3.Ni, 4.Mn, 5.Co, 6.Ni, and 8.Cu and a 3D framework for 7.Cu. The high-temperature magnetic susceptibilities are dominated by low-dimensional behavior while long-range ordering sets in at low temperatures. The Mn complexes are antiferromagnets, and the others are metamagnets. In addition, 5.Co exhibits slow magnetic relaxation behavior at low temperatures. The metamagnetism in each case is due to strong intrachain ferromagnetic interactions and weak interchain antiferromagnetic ones.     

Double-pillared cobalt Pacman complexes: synthesis, structures and oxygen reduction catalysis

The syntheses and structures of binuclear cobalt complexes of a double-pillared cofacial Schiff-base pyrrole macrocycle (L) were determined and their activity as catalysts for the oxygen reduction reaction evaluated. The new binuclear cobalt complex, [Co(2)(L)], 1 was formed in good yield using a salt-elimination method and was characterised as adopting a cofacial structure in solution by NMR spectroscopy and as its THF and pyridine solvates in the solid state by X-ray crystallography. Using a variety of spectroscopic techniques, this complex was found to react reversibly with dioxygen to form a new paramagnetic complex. Furthermore, the new aqua-hydroxy double salt [Co(2)(μ-H(3)O(2))(py)(2)(L)][BF(4)] 2 was characterised by X-ray crystallography. In acidified benzonitrile solution, 1 behaves as a catalyst for the selective four-electron reduction of dioxygen to water and showed a large improvement in efficacy compared to its o-phenylene Schiff-base analogues.     

乙酸乙酯在Al2O3-Ce0.5Zr0.5O2负载的金属氧化物催化剂上的催化燃烧

制备了Fe, Co, Cu, Cr和Mn金属氧化物催化剂, 所用载体为Al2O3-Ce0.5Zr0.5O2复合氧化物. 利用X射线衍射(XRD), 程序升温还原(TPR), 储氧量测试, BET比表面测试和光电子能谱(XPS)表征了催化剂. 并利用活性测试表征了各种催化剂对乙酸乙酯催化燃烧能力. 各种表征结果证实, 由于催化剂Mn/Al2O3-Ce0.5Zr0.5O2(1:2, 质量比)具有最多的可还原物种, Cu/Al2O3-Ce0.5Zr0.5O2(1:2)具有较多的可还原物种和最强的可还原能力, 使它们对乙酸乙酯催化燃烧表现出了最好的活性. 在催化剂Cu/Al2O3-Ce0.5Zr0.5O2(1:2)和Mn/Al2O3-Ce0.5Zr0.5O2(1:2)上, 乙酸乙酯于245 ℃转化了99%, 表明这两种催化剂具有广泛的应用潜力.     

Electrochemical metalloporphyrin-catalyzed reduction of chlorite

We measured the redox stoichiometry and rate constants for the electrochemical reduction of ClO(2)(-) at pH 7, catalyzed by a series of metalloporphyrins of Mn, Fe, and Co with different proximal and distal environments. A clean four-electron reduction was observed. The catalytic activity correlates well with that observed in reduction of H(2)O(2). The axial imidazole and/or a redox-active distal metal (Cu or Co) increases the turnover frequency in several compounds. The metalloporphyrins were inert to ClO(x)(-) (x = 3,4) and IO(3)(-) but catalyzed facile two-electron reduction of IO(4)(-); six-electron reduction of BrO(3)(-) was also observed.     

过渡金属氧化物催化剂上NH3 分解Claus反应机理研究

运用浸渍法制备了七种过渡金属氧化物催化剂.对于NH3 分解反应均可获得很高的NH3转化率;对于NH3分解Claus反应则可以获得较高的SO2转化率和单质硫选择性.通过比较发现Co3O4-TiO2和Fe2O3-TiO2催化剂的低温活性比较高.经过XRD表征发现,在NH3分解Claus反应中,催化剂的活性相可能是过渡金属硫化物.结合活性评价和XRD表征结果提出了NH3分解Claus反应的机理.