二(β-二亚胺基)二价稀土配合物催化醛/酮与亚磷酸二乙酯的氢磷化反应

研究了一系列二(β-二亚胺基)二价稀土配合物[Eu(L^(2,6-ipr2))_2·CH_3C_6H_5,L^(2,6-ipr2)=[N(2,6-^(i)Pr_2C_6H_3)C(Me)]_2CH^-(1);Eu(L^(2,6-Me2))_2(THF),L^(2,6-Me2)=[N(2,6-Me_2C_6H_3)C(Me)]_2CH^-(2);Eu(L^(2,4,6-Me3))_2(THF),L^(2,4,6-Me3)=[N(2,4,6-Me_3C_6H_2)-C(Me)]_2CH^-(3);Eu(L^(2,6-ipr2)Ph)2,L^(2,6-ipr2)Ph=[(2,6-iPr_2C_6H3_)NC(Me)CHC(Me)N(C_6H_5)]–(4);Sm(L^(2,6-ipr2))_2·CH_3C_6H_5(5);Yb(L^(2,6-ipr2)Ph)2(6);Yb(L^(2-Me))2(THF),L^(2-Me)=[N(2-Me C6H4)C(Me)]2CH–(7)]对醛/酮与亚磷酸二乙酯的氢磷化反应的催化行为.发现所有配合物都可以在温和条件下,高效地催化芳醛以及杂环芳醛与亚磷酸二乙酯的氢磷化反应,在催化剂用量为0.08 mol%,25℃,无溶剂条件下反应5 min,α-羟基膦酸酯的收率可以达到90%~99%.催化活性有赖于β-二亚胺基的结构,其活性顺序为L^(2,6-Me2)<L^(2,4,6-Me3)<L^(2,6-ipr2)≈L^(2,6-ipr2)Ph.该催化体系具有优秀的醛底物适应能力.这类二价稀土配合物也可以有效地催化未活化的酮与亚磷酸二乙酯的反应,并显示良好的底物适应能力.

汽车发动机活塞环金属材料的锰磷化处理

汽车发动机活塞环的材料有铸铁、低合金钢、高合金钢等。本文用阐述了车用金属材料的锰磷化的原理、步骤,并结合实际生产介绍了如何控制汽车发动机活塞环金属材料锰磷化处理的粗糙度问题。

磷化废水处理中膜生物反应器的应用研究

本文介绍了化学沉淀作为预处理工艺,膜生物反应器(MBR)作为主体工艺处理磷化废水,系统出水满足《污水综合排放标准》(GB8978-1996)一级标准,可以作为生产生活杂用水回用,减少新鲜水的消耗与废水排放,对同类企业有较好的借鉴意义。

碳纳米颗粒掺杂过渡金属磷化物的制备及其析氢性能研究

目的过渡金属因其优异的电催化性能被广泛研究,然而过渡金属磷化物较差的析氢活性和在酸中的不稳定性阻碍了其进一步应用。碳纳米颗粒(CNPs)具有低成本、制备工艺简单、高稳定性和高导电性等优点,可以通过添加碳材料对过渡金属磷化物的结构进行有效调控,从而提高材料的析氢活性和稳定性。方法以葡萄糖为碳源制备了富含羟基和羧基官能团的碳纳米颗粒(P-CNPs),以具有高比表面积的泡沫镍为基底,通过水热法制备掺杂P-CNPs的NiCo前驱体,再经过磷化反应得到掺杂P-CNPs的过渡金属磷化物NiCoP-PC/NF。结果在0.5 mol/L H_(2)SO_(4)和1 mol/L KOH中的阴极极化曲线表明,在电流密度10 mA/cm^(2)、碳纳米颗粒浓度50 mg/L时,NiCoP-50PC/NC的过电位分别低至59 mV和90 mV,均远小于商业Pt/C;同时,NiCoP-50PC/NF在0.5 mol/L H_(2)SO_(4)和1 mol/L KOH中的阴极极化曲线几乎重合,表明析氢活性没有发生明显的衰减,具有良好的电化学稳定性。结论碳纳米颗粒掺杂方法为提高过渡金属材料析氢性能提供了一种新的思路。

铝合金表面磷化工艺研究

介绍了铝合金表面磷化膜形成的基本反应机理,详细分析了铝合金磷化反应前处理,磷化反应过程中三个区域的作用及磷化速度的影响因素,并对影响磷化膜质量的因素如磷化工艺参数、磷化液成分及磷化前后处理等进行了研究。

镍铁钴磷化物纳米片阵列的制备及其电催化析氧性能

采用溶剂热法将镍、铁和钴的硝酸盐溶液在180℃条件下反应24 h,经过后续磷化反应,在泡沫镍基底上生长镍铁钴磷化物纳米片阵列(NiFeCoP@NF).采用X射线衍射、扫描电子显微镜、透射电子显微镜、X射线光电子能谱等测试手段对材料进行了表征,并用电化学工作站研究了镍铁钴磷化物纳米片阵列的析氧性能.结果表明:当电流密度达到10 mA/cm^ 2时,需要的过电势仅为160 mV,并且在恒定电流密度下,过电势可保持24 h.研究结果对于研究纳米结构的过渡金属磷化物电催化剂具有借鉴意义.

低温磷化液的研制及开发

本文介绍了华夏磷化有限公司研制的低温磷化液的配方。

成膜处理剂(Ⅱ)

20 钙离子的质量浓度对磷化的影响 Ca^2＋的质量浓度过低或过高,对磷化都不利.过低时,膜层不均匀、泛黄、颜色浅;过高时,虽然磷化膜的耐蚀性较好,但磷化反应慢（反应时间延长至8～15 min）,气泡小而少.同时Ca^2＋过多,在配槽溶液使用过程中容易产生沉淀.此时适当升高游离酸度.此外,钙系磷化液有不稳定性.因为Ca^2＋对SO4^2-,F^-的敏感性大,不易得到均匀磷化膜.

Influence of phosphoric anions on oxygen reduction reaction activity of platinum, and strategies to inhibit phosphoric anion adsorption

Nation-membrane-based proton exchange fuel cells （PEMFCs） typically operate at below 100 ℃. However, H3PO4-doped polybenzimidazole （PBI）-based PEMFCs can operate at 100-200 ℃. This is advantageous because of accelerated reaction rates and enhanced tolerance to poisons such as CO and S02, which can arise from reformed gas or the atmosphere. However, the strong adsorption of phosphoric anions on the Pt surface dramatically decreases the electrocatalytic activity. This study exploits the ＂third-body effect＂, in which a small amount of organic molecules are pre-adsorbed on the Pt surface to inhibit the adsorption of phosphoric anions. Pre-adsorbate species inhibit the ad- sorption of phosphoric anions, but can also partially occlude active sites. Thus, the optimum pre-adsorbate coverage is studied by correlating the oxygen reduction reaction （ORR） activity of Pt with pre-adsorbate coverage on the Pt surface. The influence of the pre-adsorbate molecule length is investigated using the organic amines, butylamine, octylamine, and dodecylamine, in both 0.1 mol/L HCI04 and 0.1 mol/L H3P04. Such amines readily bond to the Pt surface. In aqueous HCI04 electrolyte, the ORR activity of Pt decreases monotonically with increasing pre-adsorbate coverage. In aqueous H3P04 electrolyte, the ORR activity of Pt initially increases and then decreases with in- creasing pre-adsorbate coverage. The maximum ORR activity in H3P04 occurs at a pre-adsorbate coverage of around 20%. The effect of molecular length of the pre-adsorbate is negligible, but its coverage strongly affects the degree to which phosphoric anion adsorption is inhibited. Butylamine adsorbs to Pt at partial active sites, which decreases the electrochemically active surface area. Ad- sorbed butylamine may also modify the electronic structure of the Pt surface. The ORR activity in the phosphoric acid electrolyte remains relatively low, even when using the pre-adsorbate modified Pt/C catalysts. Further development of the catalyst and electrolyte is required before the commercialization of H3PO4-PBl-based PEMFCs can be realized.

CoNiP/NC polyhedrons derived from cobalt-based zeolitic imidazolate frameworks as an active electrocatalyst for oxygen evolution

The oxygen evolution reaction(OER)plays an important role in the development of energy conversation and storage technologies including water splitting and metal-air batteries,where the development of electrocatalysts is paramount.In this study,cobalt-nickel phosphide/N-doped porous carbon polyhedron electrocatalysts(CoNiP/NC)were prepared by a facile two-step carbonization method and subsequent phosphorization calcination in an Ar atmosphere using cobalt-based zeolitic imidazolate frameworks(ZIFs)as precursors.Among the electrocatalysts obtained by controlling the carbonization and phosphorization temperature,the CoNiP/NC700 catalyst,where 700 refers to the calcination temperature(°C),exhibited superior electrocatalytic activity for the OER with an onset overpotential of approximate 220 mV and an overpotential of approximate 300 mV in alkaline solution at a current density of 10 mA/cm2.The CoNi/NC and Co/NC Samples were also tested for comparison and CoNiP/NC exhibited the better electrocatalytic activity at all the temperatures tested.The superior electrocatalytic activity of the phosphorization hybrid material can be attributed to the superior synergistic effect of Co,Ni,P and C due to their strong electron coupling interactions.The interconnected amorphous carbon anchored the active Co compounds to avoid aggregation and maintained conducting channels for electron transfer.The composite electrocatalyst prepared herein is a promising candidate for use in electrocatalytic OERs.

Strategies on improving the electrocatalytic hydrogen evolution performances of metal phosphides

Among the sustainable energy sources,hydrogen is the one most promising for alleviating the pollution issues related to the usage of conventional fuels,as it can be produced in an efficient and eco-friendly way via electrocatalytic water splitting.The hydrogen evolution reaction(HER,a half-reaction of water splitting)plays a pivotal role in decreasing the price and increasing the catalytic efficiency of hydrogen production and is efficiently promoted by metal phosphides in different electrolytes.Herein,we summarize the recent advances in the development of metal phosphides as HER electrocatalysts,focus on their synthesis(post-treatment,in situ generation,and electrodeposition methods)and the enhancement of their electrocatalytic activity(via elemental doping,interface and vacancy engineering,construction of specific supports and nanostructures,and the design of bior polymetallic phosphides),and highlight the crucial issues and challenges of future development.

Identification and Metabolic Mechanism of Non-fermentative Short-cut Denitrifying Phosphorus-removing Bacteria

To investigate the characteristics and metabolic mechanism of short-cut denitrifying phospho- rus-removing bacteria （SDPB） that are capable of enhanced biological phosphorus removal （EBPR） using nitrite as an electron acceptor, an aerobic/anoxic sequencing batch reactor was operated under three phases. An SDPB-strain YC was screened after the sludge enrichment and was identified by morphological, physiological, biochemical properties and 16S rDNA gene sequence analysis. Denitrifying phosphorus-removing experiments were conducted to study anaerobic and anoxic metabolic mechanisms by analyzing the changes of chemical oxygen demand （COD）, phosphate, nitrite, poly-fl-hydroxybutyrate （PHB）, and glycogen. The results show that strain YC is a non-fermentative SDPB similar to Paracoccus denitrificans. As a kind of non-fermentative bacteria, the energy of strain YC was mainly generated from phosphorus release （96.2%） under anaerobic conditions with 0.32 mg P per mg synthesized PHB. Under anoxic conditions, strain YC accumulated 0.45 mg P per mg degraded PHB, which produced most of energy for phosphate accumulation （91.3%） and a little for glycogen synthesis （8.7%）. This metabolic mechanism of strain YC is different from that of traditional phosphorus-accumulating organisms （PAOs）. It is also found that PHB, a kind of intracellular polymer, plays a very important role in denitrifying and accumulating phosphorus by supplying sufficient energy for phosphorous accumulation and carbon sources for denitrification. Therefore, monitoring AP/APHB and ANO2 -N/APHB is more necessary than monitoring AP/ACOD, ANO2 -N/ACOD, or AP / ANO2 -N.

Effects of phosphate precursors on morphology and oxygen evolution reaction activity of NiFe(oxy)hydroxide on nickel foams

NiFe(oxy)hydroxides nanosheets were synthesized on nickel foams via co-precipitation and electrochemical activation. It is found that the phosphate precursors(Na_(3)PO_(4), Na_(2)HPO_(4)and NaH_(2)PO_(4)) have diverse effects on the morphology and thus the oxygen evolution reaction activity of the formed final catalysts. The resulting NiFe(oxy)hydroxides nanosheets prepared with Na_(2)HPO_(4)demonstrate a low overpotential of 205 m V to achieve a current density of 50 mA/cm^(2) with a Tafel slope down to 30 mV/dec in 1 mol/L KOH, and remain stable for 20 h during stability test.

Denitrification and Dephosphatation by Anaerobic/Anoxic Sequencing Batch Reactor

Removal of denitrifying phosphorus was verified in a laboratory anaerobic/anoxic sequencing batch reactor (A/A SBR). The results obtained demonstrated that the anaerobic/anoxic strategy can enrich the growth of denitrifying phosphorus removing bacteria (DPB) and take up phosphate under anoxic condition by using nitrate as the electron acceptor. The phosphorus removal efficiency was higher than 90% and the effluent phosphate concentration was lower than 1 mg·L-1 after the A/A SBR was operated in a steady-state. When the chemical oxygen demand(COD) of influent was lower than 180mg· L-1, the more COD in the influent was, the higher efficiency of phosphorus removal could be attained under anoxic condition. However, simultaneous presence of carbon and nitrate would be detrimental to denitrifying phosphorus removal. Result of influence of sludge retention time (SRT) on denitrifying phosphorus removal suggested that the decrease of SRT caused a washout of DPB and consequently the enhanced biological phosphorus removal decreased with 8 days SRT. When the SRT was restored to 16 days, however, the efficiency of phosphorus removal was higher than 90%.

Mitotic phosphorylation of PRC1 at Thr470 is required for PRC1 oligomerization and proper central spindle organization

During cell division, chromosome segregation is orchestrated by the interaction of spindle microtubules with the centromere. A dramatic remodeling of interpolar microtubules into an organized central spindle between the separating chromatids is required for the initiation and execution ofcytokinesis. Central spindle organization requires mitotic kinesins, the chromosomal passenger protein complex, and microtubule bundling protein PRC 1. PRC 1 is phosphorylated by Cdc2 at Thr470 and Thr481 during mitosis. However, the functional relevance of PRC 1 phosphorylation at Thr470 has remained elusive. Here we show that expression of the non-phosphorylatable mutant PRC 1T470A but not the phospho-mimicking mutant PRC 1^T470E causes aberrant organization of the central spindle. Immunoprecipitation experiment indicates that both PRC 1^T470A and PRC 1^T470E mutant proteins associate with wild-type PRC 1, suggesting that phosphorylation of Thr470 does not alter PRC 1 self-association. In addition, in vitro co-sedimentation experiment showed that PRC 1 binds to microtubule independent of the phosphorylation state of Thr470. Gel-filtration experiment suggested that phosphorylation of Thr470 promotes oligomerization of PRC 1. Given the fact that prevention of the Thr470 phosphorylation inhibits PRC 1 oligomerization in vitro and causes an aberrant organization of central spindle in vivo, we propose that this phosphorylation-dependent PRC 1 oligomerization ensures that central spindle assembly occurs at the appropriate time in the cell cycle.

CMAS corrosion resistance characteristics of RE_(50)Ta_(x)Zr_(50-x)O_(175+0.5x)thermal barrier oxides in RE_(2)Zr_(2)O_(7)-RETaO_(4)systems

The corrosion resistance characteristics of RE-rich RE_(50)Ta_(x)Zr_(50-x)O_(175+0.5x)oxides in RE_(2)Zr_(2)O_(7)-RETaO_(4)systems to calcium-magnesium-alumino-silicate(CMAS)at 1300°C,and the influence of RE^(3+)and Ta^(5+)on chemical reactions and reactive crystallization of CMAS melts were investigated.The results show that following the thermochemical reactions,apatite,pyrochlore,reprecipitated fluorite and residual Yb(Y)TaO4phases were the predominant reaction products.Formation abilities of apatite and pyrochlore were found to be proportional to the ionic radius of RE^(3+).The increase of Ta^(5+)amount can decrease the number of available RE^(3+)to form apatite.Moreover,the resistance characteristic to CMAS corrosion in RE_(50)Ta_(x)Zr_(50-x)O_(175+0.5x)systems was decided by the combined action of apatite and pyrochlore phases.The cohesive mixture of apatite and pyrochlore phases can generate a dense layer near the reaction front,which had a positive effect on suppressing CMAS infiltration.The ability of the fluorite+RETaO4two-phase field was determined to be sufficient to mitigate CMAS corrosion.

Recent developments in metal phosphide and sulfide electrocatalysts for oxygen evolution reaction

Oxygen evolution reaction(OER),as an important half‐reaction involved in water splitting,has been intensely studied since the last century.Transition metal phosphide and sulfide‐based compounds have attracted increasing attention as active OER catalysts due to their excellent physical and chemical characters,and massive efforts have been devoted to improving the phosphide and sulfide‐based materials with better activity and stability in recent years.In this review,the recent progress on phosphide and sulfide‐based OER electrocatalysts in terms of chemical properties,synthetic methodologies,catalytic performances evaluation and improvement strategy is reviewed.The most accepted reaction pathways as well as the thermodynamics and electrochemistry of the OER are firstly introduced in brief,followed by a summary of the recent research and optimization strategy of phosphide and sulfide‐based OER electrocatalysts.Finally,some mechanistic studies of the active phase of phosphide and sulfide‐based compounds are discussed to give insight into the nature of active catalytic sites.It is expected to indicate guidance for further improving the performances of phosphide and sulfide‐based OER electrocatalysts.

High activity and durability of carbon-supported core-shell PtPx@Pt/C catalyst for oxygen reduction reaction

Alloying Pt with transition metals can significantly improve the catalytic properties for the oxygen reduction reaction(ORR).However,the application of Pt-transition metal alloys in fuel cells is largely limited by poor long-term durability because transition metals can easily leach.In this study,we developed a nonmetallic doping approach and prepared a P-doped Pt catalyst with excellent durability for the ORR.Carbon-supported core-shell nanoparticles with a P-doped Pt core and Pt shell(denoted as PtPx@Pt/C)were synthesized via heat-treatment phosphorization of commercial Pt/C,followed by acid etching.Compositional analysis using electron energy loss spectroscopy and X-ray photoelectron spectroscopy clearly demonstrated that Pt was enriched in the near-surface region(approximately 1 nm)of the carbon-supported core-shell nanoparticles.Owning to P doping,the ORR specific activity and mass activity of the PtP_(1.4)@Pt/C catalyst were as high as 0.62 mA cm^(–2)and 0.31 mAμgPt–^(1),respectively,at 0.90 V,and they were enhanced by 2.8 and 2.1 times,respectively,in comparison with the Pt/C catalyst.More importantly,PtP_(1.4)@Pt/C exhibited superior stability with negligible mass activity loss(6%after 30000 potential cycles and 25%after 90000 potential cycles),while Pt/C lost 46%mass activity after 30000 potential cycles.The high ORR activity and durability were mainly attributed to the core-shell nanostructure,the electronic structure effect,and the resistance of Pt nanoparticles against aggregation,which originated from the enhanced ability of the PtP_(1.4)@Pt to anchor to the carbon support.This study provides a new approach for constructing nonmetal-doped Pt-based catalysts with excellent activity and durability for the ORR.

A Reduced Mechanism for Flame Inhibition by Phosphorus-containing Compounds Based on Level of Importance Analysis

A reduced mechanism for propane/air combustion and its flame inhibition by phosphorus-containing compounds (PCCs) is constructed with the level of importance (LOI) method. The analysis is performed on solutions of freely propagating premixed flames with detailed chemical kinetics involving 121 species and 682 reactions proposed by Jayaweera et al. For the non-homogeneous reaction-diffusion system, the chemical lifetime of each species is weighted by its diffusion timescale, and the characteristic flame timescale is used to normalize the chemical lifetime. The definition of sensitivity in LOI is extended so that multi-parameters can be used as sensitivity targets. Propane, oxygen, dimethyl methylphosphonate (DMMP), and flame speed are selected to be perturbed for sensitivity analysis, the species with low LOI index are removed, and reactions involving the redundant species are excluded from the mechanism. A skeletal mechanism is obtained, which consists of 57 species and 268 elementary reactions. Calculations for laminar flame speeds, key flame radicals and catalytic cycles using the skeletal mechanism are in good agreement with those by using the detailed mechanism over a wide range of equivalence ratio undoped and doped with DMMP.