基于金属钴配合物的均相光催化还原二氧化碳研究进展

本文综述了自20世纪80年代以来基于钴配合物的均相光催化二氧化碳还原研究成果,以钴配合物催化剂的结构分类并结合时间顺序回顾了近四十年来该领域的发展轨迹,重点总结了用于光催化二氧化碳还原研究的金属钴配合物的结构、催化活性以及光催化体系的构成等特点,分析了该领域面临的挑战并展望了未来的发展方向。     

CO2对Cu-Ce-O催化剂催化氧化CO活性的影响

用CO作为探针研究CeO。的表面性质,以及研究CO和CO。与CeO。的相互作用,已有不少报导［‘－’1．Br。ysse等人发现CO在CeO。上的吸附,总伴随着催化剂的还原和COZ的生成;CO。在CeO。上的吸附不总是可逆的,CO。的存在会降低其对CO的催化氧化活性,对反应有抑制的影响,甚至会使表面中毒问．也有报导在CO或COZ气氛下,有证据表明CeO。有不利干活性的碳酸盐物种形成;反应中生成的C（）。也可能吸附在表面上形成稳定的碳酸盐,从而抑制反应的继续进行k‘］．＊0。对O;－O－（）催化剂在催化氧化以）中的影响报导比较少问．…     

PRODUCTION OF LIGHT OLEFINS FROM CO2 HYDROGENATION OVER Fe/SILICALITE-2 CATALYST. I.CATALYTIC REACTIVI-FY AND REACTION MECHANISM

K-Fe-MnO/Silicalite-2 is a desirable catalyst for the production of light olefins from CO2 hydrogenation The activity can be improved greatly with increasing the Fe loading, and the selectivities to hydrocarbons rise with Fe loading increase However, an ambiguous effect of Fe loading on the selectivity of light olefin in hydrocarbon products is observed. The CO2 hydrogenation containing a two-step mechanism CO2+H2=CO+H2O, a reversible water gas shift reaction, and CO+(m/2n+1)H2 =1/nCnHm+H2O2, a Frscher-Tropsch reaction, is suggested by the results of CO2-TPD and CO2/H2-TPSR as well as CO/H2-TPSR characterizations.     

Versatile behavior of the fluorophosphinidene ligand in iron carbonyl chemistry

Fluorophosphinidene (PF) is a versatile ligand found experimentally in the transient species M(CO)(5)(PF) (M = Cr, Mo) as well as the stable cluster Ru(5)(CO)(15)(μ(4)-PF). The PF ligand can function as either a bent two-electron donor or a linear four-electron donor with the former being more common. The mononuclear tetracarbonyl Fe(PF)(CO)(4) is predicted to have a trigonal bipyramidal structure analogous to Fe(CO)(5) but with a bent PF ligand replacing one of the equatorial CO groups. The tricarbonyl Fe(PF)(CO)(3) is predicted to have two low-energy singlet structures, namely, one with a bent PF ligand and a 16-electron iron configuration and the other with a linear PF ligand and the favored 18-electron iron configuration. Low-energy structures of the dicarbonyl Fe(PF)(CO)(2) have bent PF ligands and triplet spin multiplicities. The lowest energy structures of the binuclear Fe(2)(PF)(CO)(8) and Fe(2)(PF)(2)(CO)(7) derivatives are triply bridged structures analogous to the experimental structure of the analogous Fe(2)(CO)(9). The three bridges in each Fe(2)(PF)(CO)(8) and Fe(2)(PF)(2)(CO)(7) structure include all of the PF ligands. Other types of low-energy Fe(2)(PF)(2)(CO)(7) structures include the phosphorus-bridging carbonyl structure (FP)(2)COFe(2)(CO)(6), lying only ~2 kcal/mol above the global minimum, as well as an Fe(2)(CO)(7)(μ-P(2)F(2)) structure in which the two PF groups have coupled to form a difluorodiphosphene ligand unsymmetrically bridging the central Fe(2) unit.     

Sugar acetates as novel,renewable CO(2)-philes

Acetylation of carbohydrates is proposed as a method for the synthesis of inexpensive CO2-philes that can easily be modified for a wide variety of green chemistry applications in liquid and supercritical CO2. The deliquescence of peracetylated sugars in contact with CO2 is reported in this communication as well as the unparalleled solubility of these compounds in supercritical CO2.     

Factors affecting 13C-natural abundance measurement of breath carbon dioxide during surgery: absorption of carbon dioxide during endoscopic procedures

The aim of this paper is to review the factors which may affect breath (13)CO(2)/(12)CO(2) natural abundance in patients undergoing surgery or intensive care. Intravenous glucose administration is a major determinant of the (13)CO(2)/(12)CO(2) of breath as intravenous glucose preparations are almost all derived from cornstarch. In addition, the oxidation of endogenous substrates can affect the (13)CO(2)/(12)CO(2) ratio. During many endoscopic procedures, such as laparoscopic surgery, carbon dioxide insufflation is used to provide a working space. As medical CO(2) is relatively depleted in (13)CO(2) compared with endogenous and exogenous metabolic CO(2) sources, breath (13)CO(2)/(12)CO(2) measurements can be used to estimate CO(2) absorption during these procedures. However, all these factors may also be affected by the bicarbonate pool, making a definitive attribution of changes in breath (13)CO(2)/(12)CO(2) to a single factor problematic.     

可逆与不可逆吸附CO在合成甲醇反应中的作用

合成甲醇反应是CO+H_2反应系列中较简单的反应之一,它与同系列的甲烷化反应有着不同的反应条件.从热力学观点来看,甲烷化反应和合成甲醇反应同是体积缩小反应,加压应该有利于两反应的进行,实际上合成甲醇反应需加压,而甲烷化反应却不一定需要加压.最近我们用动态分析技术对烃的临氢转化、乙炔加氢和苯加氢反应研究发现,在实际反应条件下,反应物在催化剂表面上的吸附可分为可逆与不可逆吸附两类,它们在多相催化反应中对活性、选择性和稳定性均有影响,但是它们对操作压力的依赖程度是不一样的.因此研究     

Crocodile Oil Modulates Inflammation and Immune Responses in LPS-Stimulated RAW 264.7 Macrophages

Crocodile oil (CO) is generated from the fatty tissues of crocodiles as a by-product of commercial aquaculture. CO is extensively applied in the treatment of illnesses including asthma, emphysema, skin ulcers, and cancer, as well as wound healing. Whether CO has anti-inflammatory properties and encourages an immune response remains uncertain. The impact of CO on inflammatory conditions in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells and the mechanisms behind it were examined in this work. Cells were treated with 0.125–2% CO dissolved in 0.5% propylene glycol with or without LPS. The production and expression of inflammatory cytokines and mediators were also examined in this research. CO reduced the synthesis and gene expression of interleukin-6 (IL-6). Consistently, CO inhibited the expression and synthesis of inflammatory markers including cyclooxygenase-2 (COX-2), prostaglandin E2 (PGE2), nitric oxide (NO), and nuclear factor kappa B (NF-κB). Furthermore, CO reduced the effects of DNA damage. CO also increased the cell-cycle regulators, cyclins D2 and E2, which improved the immunological response. CO might thus be produced as a nutraceutical supplement to help avoid inflammatory diseases.     

CO2在金属表面活化的UBI-QEP方法研究

应用UBI-QEP方法估算了金属表面上形成的活化吸附态CO₂^-在Cu(111),Pd(111),Fe(111)和Ni(111)表面上的吸附热,计算了各种相关反应的活化能垒.结果表明,CO₂^-在4种过渡金属表面的相对稳定性的顺序为Fe>Ni>Cu>Pd;在Fe和Ni表面上CO₂^-较易生成,且容易进一步发生解离反应,在Fe表面会解离成C和O吸附原子,而在Ni表面上解离的最终产物为CO和O;在Cu表面上,CO₂^-虽较难形成,但其加氢反应的活化能比解离反应低,因此加氢反应是其进一步活化的有效模式;在Pd表面上,CO₂^-吸附态在能量上很不稳定,所以CO₂在Pd表面上不容易活化.     

CO adsorption on a Pt(111) surface partially covered with FeO_x nanostructures

The adsorption of CO on Pt group metals, as a most fundamental elementary reaction step, has been widely studied in catalysis and electrocatalysis. Particularly, the structures of CO on Pt(111) have been extensively investigated, owing to its importance to both fundamental and applied catalysis. Yet, much less is known regarding CO adsorption on a Pt(111) surface modulated by supported oxide nanostructures,which is of more relevance to technical catalysis. We thus investigated the coverage-dependent adsorption of CO on a Pt(111) surface partially covered by Fe Oxnanostructures, which has been demonstrated as a remarkable catalyst for low-temperature CO oxidation. We found that, due to its strong chemisorption, the coverage-dependent structure of CO on bare Pt is not influenced by the presence of Fe Ox. But,oxygen-terminated Fe Oxnanostructures could modulate the diffusivity of CO at their vicinity, and thus affect the formation of ordered CO superstructures at low temperatures. Using scanning tunneling microscopy(STM), we inspected the diffusivity of CO, followed the phase transitions of CO domains, and resolved the molecular details of the coverage-dependent CO structures. Our results provide a full picture for CO adsorption on a Pt(111) surface modulated by oxide nanostructures and shed lights on the inter-adsorbate interaction on metal surfaces.     

不同形态ZrO2负载Co催化剂上CO+H2吸附与反应行为研究

利用FTIR,TPSR和微量反应技术考察了CO和CO/H2在无定形、四方相和单斜相3种形态氧化锆为载体的钴基催化剂上的吸附和反应行为.结果表明,CO在以不同形态氧化锆为载体的催化剂上的吸附形式和转化行为具有较大差异.在单斜氧化锆为载体的催化剂上生成桥式和多桥式吸附的CO,并容易进一步加氢生成烃类物种,具有较高的反应活性和C5+烃的选择性.而以四方氧化锆为载体的催化剂上桥式吸附的CO较稳定,加氢反应活性较低.     

Binuclear manganese and rhenium carbonyls M2(CO)n (n = 10, 9, 8, 7): comparison of first row and third row transition metal carbonyl structures

The equilibrium geometries, thermochemistry, and vibrational frequencies of the homoleptic binuclear rhenium carbonyls Re2(CO)n (n = 10, 9, 8, 7) were determined using the MPW1PW91 and BP86 methods from density functional theory (DFT) with the effective core potential basis sets LANL2DZ and SDD. In all cases triplet structures for Re2(CO)n were found to be unfavorable energetically relative to singlet structures, in contrast to corresponding Mn2(CO)n derivatives, apparently owing to the larger ligand field splitting of rhenium. For M2(CO)10 (M = Mn, Re) the unbridged structures (OC)5M-M(CO)5 are preferred energetically over structures with bridging CO groups. For M2(CO)9 (M = Mn, Re) the two low energy structures are (OC)4M(micro-CO)M(CO)4 with an M-M single bond and a four-electron donor bridging CO group and (OC)4M[double bond, length as m-dash]M(CO)5 with no bridging CO groups and an M[double bond, length as m-dash]M distance suggesting a double bond. The lowest energy structures for Re2(CO)8 have Re[triple bond, length as m-dash]Re distances in the range 2.6-2.7 A suggesting the triple bonds required to give the Re atoms the favored 18-electron configuration. Low energy structures for Re2(CO)7 are either of the type (OC)(4)M[triple bond, length as m-dash]M(CO)3 with short metal-metal distances suggesting triple bonds or have a single four-electron donor bridging CO group and longer M-M distances consistent with single or double bonds. The 18-electron rule thus appears to be violated in these highly unsaturated Re2(CO)7 structures.     

Pt/Al2O3整体催化剂上选择性氧化脱除甲醇重整氢源中CO --副反应对CO脱除效果的影响分析

移动甲醇重整制氢是质子交换膜燃料电池（PEMFC）可行的供氢方式之一,包括水蒸气重整、部分氧化重整和自热重整。甲醇重整制氢方法不同,重整气体积组成在H245％～75％,CO215％～25％,CO1％～10％,H2O10％～20％和N20—20％变化。重整气进入PEMFC之前要经过CO水蒸气变换反应（如果采用水蒸气重整,不需要变换过程）,     

PRODUCTION OF LIGHT OLEFINS FROM CO_2 HYDROGENATION OVER Fe/SILICALITE-2 CATALYST Ⅰ.CATALYTIC REACTIVI-FY AND REACTION MECHANISM

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A Two‐Photon H2O2‐Activated CO Photoreleaser

Carbon monoxide (CO) is proposed as an active pharmaceutical agent with promising pharmaceutical prospects, as it has been involved in multifaceted modulation of diverse physiological and pathological processes. However, questions remain for therapeutic application of inhaled CO attributed to the inherent great affinity between CO and hemoglobin. Therefore, a robust platform with the function of CO transport and controllable release, depending on the local status of an organism, is of prominent significance for effectively avoiding the side effects of CO inhalation and optimizing the biological regulation function of CO. Utilizing the oxidative stress biomarker H₂O₂ as a trigger and combining with photo‐control, a two‐photon H₂O₂‐activated CO photoreleaser, FB, featuring highly sensitive and specific H₂O₂ sensing and photocontrollable CO release, was developed and the vasodilation effect of CO against angiotensin II was demonstrated.     

RhCo双金属催化剂的研究III. Rh+Co/Al2O3上表面羰基氢化物及其动态行为

利用连续流动微反研究了Rh+Co/Al2O3催化剂的CO加氢反应, 结果表明反应在220℃以上发生, 反应活性随着温度的升高和H2/CO值的增加而增加。利用TP-IR动态方法研究了Rh+Co/Al2O3上CO和H2共吸附及其动态行为。结果表明在Rh+Co/Al2O3的孪生及线式中心上, CO和H2室温共吸附时即有部分孪生及线式CO转化为相应的羰基氢化物, 随着温度的升高, 剩余的孪生和线式CO继续向相应的羰基氢化物转化。而羰基氢化物则向多羰基氢化物转化。在到达反应温度之前, 催化剂表面只存在羰基氢化物及相应的多氢羰基氢化物。在反应温度则导致产物CH4生成。与CO加氢反应和CO歧化的吸附态研究结果相关联, 作者认为Rh+Co/Al2O3上CO加氢生成CH4是经由羰基氢化物-多氢羰基氢化物途径。     

超细Cu-ZnO-ZrO2催化剂上甲醇合成的TPSR和TPD研究

采用ＭＳ－ＴＰＳＲ和ＭＳ－ＴＰＤ技术在不同粒度的超细Ｃｕ－ＺｎＯ－ＺｒＯ２催化上考查了ＣＯ２和ＣＯ加氢合成甲醇的反应过程和吸附活化特征。研究表明,ＣＯ２和ＣＯ都可以直接加氢合成甲醇。     

Spectroscopic identification of the CO-H2O 2-1 cluster trapped in an argon matrix

The infrared spectra of the carbon monoxide-water cluster as well as the CO monomer and dimer in an argon matrix at cryogenic temperatures have been reinvestigated on the basis of the isotope substitution experiment with 12CO and 13CO. Lines due to the CO-H2O 2-1 cluster in the matrix have been unambiguously identified in the CO and OH stretching regions. The isotope effect on the vibrational frequency of the cluster is observed in the CO stretching vibration but neither in the symmetric nor antisymmetric OH stretching vibrations. Each of the two vibrational lines due to the two CO vibrations of the CO-H2O 2-1 cluster is examined by comparing the expected spectral features at a 12CO/13CO ratio on a simulation with those observed experimentally. The migration of the trapped molecules (CO and H2O) in the matrix is discussed, in which the observed spectral change with the deposition temperature from 14 K to 30 K is explained.     

Nitrogen-doped graphene as an excellent candidate for selective gas sensing

The toxic gases,such as CO and NO,are highly dangerous to human health and even cause the death of person and animals in a tiny amount.Therefore,it is very necessary to develop the toxic gas sensors that can instantly monitor these gases.In this work,we have used the first-principles calculations to investigate adsorption of gases on defective graphene nanosheets to seek a suitable material for CO sensing.Result indicates that the vancancy graphene can not selectivly sense CO from air,because O2 in air would disturb the sensing signals of graphene for CO,while the nitrogen-doped graphene is an excellent candidate for selectivly sensing CO from air,because only CO can be chemisorbed on the pyridinic-like N-doped graphene accompanying with a large charge transfer,which can serve as a useful electronic signal for CO sensing.Even in the environment with NO,the N-doped graphene can also detect CO selectively.Therefore,the N-doped graphene is an excellent material for selectively sensing CO,which provides useful information for the design and fabrication of the CO sensors.     

PRODUCTION OF LIGHTOLEFINS FROM CO_2 HYDROGENATION OVER Fe/SILICALITE-2 CATALYST Ⅱ. PROMOTION EFFECT OF MnO PROMOTER

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