Co3O4/CeO2的氧化还原性能及反应条件对其CO氧化活性的影响

采用沉淀氧化法制备了Co₃O₄/CeO₂催化剂。运用XRD、BET和TPR表征手段,考察了不同钴铈比及焙烧温度对钴铈复合氧化物物理及化学性能的影响,并分别在干、湿条件下进行了一氧化碳氧化反应研究。结果表明,与纯的Co₃O₄相比,在不同比例的Co₃O₄/CeO₂均经723 K焙烧的各种催化剂中,钴铈原子比为9∶1的复合氧化物粒径较小,比表面积较大,说明适当比例铈的添加能使Co₃O₄具有较小的粒径。此氧化物经538 K温度焙烧制得的钴铈比为9∶1的复合氧化物中Co₃O₄平均粒径为7.2 nm, BET比表面积为167.6 m²/g。经TPR考察发现其具有最优的氧化还原性能。     

RgCo双金属催化剂的研究IV. Rh2Co2/Al2O3上的吸附中心类型及吸附性能

利用CO和NO作为双探针分子对Rh2Co2/Al2O3的吸附中心类型和吸附性能进行了详细的研究。结果表明Rh2Co2/Al2O3上存在Rh上的孪生和桥式CO吸附中心以及Co上的线式CO吸附中心。其中Rh上的孪生和桥式CO吸附中心对CO和NO的吸附性能与Rh4/Al2O3上的孪生和桥式CO中心相似。Co上的线式CO吸附中心以预吸附的CO能被NO取代, 预吸附的NO不能被CO取代而区别于Rh4/Al2O3上的Rh的线式CO吸附中心; 又以既能吸附CO又能吸附NO而不同于Co2/Al2O3和Rh+Co/Al2O3上的Co中心。与母体簇的结构相关联, 表明H2还原后的Rh2Co2/Al2O3上Rh2Co2(CO)12簇结构仍保持, 且Rh-Co相互作用强。     

NF/rGO/Co_3O_4/NiO电极的制备及在超级电容器中的应用

以泡沫镍(NF)为集流体,在优化好的电位、时间和浓度下,将还原氧化石墨烯(rGO)、金属氧化物(Co_3O_4和NiO)直接生长在泡沫镍上,制备了NF/rGO/Co_3O_4和NF/rGO/Co_3O_4/NiO电极.运用三电极体系对电极材料进行了恒流充放电(GCD)和交流阻抗(EIS)等测试.结果表明,复合材料NF/rGO/Co_3O_4/NiO具有较高的比容量(电流密度为2 A/g时,比容量达到1188.6 F/g)和较好的循环稳定性(2000周充放电后,稳定性达到80.5%).该材料还具有较高的倍率性能,当电流密度由2 A/g增至12 A/g时,倍率性能仍能达到75.7%.     

The donor ability of the chelated carbonate ligand: protonation and metallation of [(L)Co(O2CO)]+ complexes in aqueous solution

The syntheses and X-ray structures of [Co(Me-tpa)O(2)COZnCl(3)], [Co(pmea)O(2)COZnCl(3)].H(2)O [Co(trpyn)O(2)COZn(OH(2))(4)OCO(2)Co(trpyn)](ZnCl(4))(2).H(2)O, [Co(trpyn)(O(2)COH)]ZnCl(4).3H(2)O and [Co(trpyn)(O(2)CO)]ClO(4) are reported (Me-tpa = [(6-methyl-2-pyridyl)methyl]bis(2-pyridylmethyl)amine, pmea = bis(2-pyridylmethyl)-2-(2-pyridylethyl)amine, trpyn = tris(2-(1-pyrazolyl)ethyl)amine). The chelated bicarbonate complex [Co(trpyn)(O(2)COH)]ZnCl(4).3H(2)O is isolated as a crystalline solid from an acidic solution of the parent carbonate [Co(trpyn)(O(2)CO)]ClO(4), and X-ray structural analysis shows that lengthening of the C[double bond, length as m-dash]O(exo) bond and shortening of the C-O(endo) bond accompanies protonation. The bimetallic complex [Co(Me-tpa)O(2)COZnCl(3)] results from the unexpected coordination of ZnCl(3)(-) to the exo O atom of a chelated carbonate ligand. This complex is obtained from both acidic and neutral solutions in which [Zn(2+)] = 1.0 M, while the structurally similar complex [Co(pmea)O(2)COZnCl(3)].H(2)O is isolated from an analogous neutral solution. The trimetallic complex [Co(trpyn)O(2)COZn(OH(2))(4)OCO(2)Co(trpyn)](ZnCl(4))(2).H(2)O crystallises on prolonged standing of [Co(trpyn)(O(2)CO)]ClO(4) in a neutral solution having [Zn(2+)] = 1.0 M. The Zn-O bond lengths in all three complexes are indicative of bonds of significant strength. DFT calculations show that the nature of the bonding interaction between the Co(iii) ion and the endo O atoms of the carbonate ligand remain essentially unaffected by coordination of Zn(2+) to the exo O atom. They also show that such coordination of Zn(2+) decreases the C-O(exo) bond order.     

Intrinsic peroxidase-like activity and catalase-like activity of Co3O4 nanoparticles

We demonstrate that Co(3)O(4) nanoparticles (NPs) exhibit intrinsic peroxidase-like activity and catalase-like activity. The peroxidase-like activity of the Co(3)O(4) NPs originates from their ability of electron transfer between reducing substrates and H(2)O(2), not from ˙OH radical generated. As peroxidase mimetics, Co(3)O(4) NPs were used for colorimetric determination of H(2)O(2) and glucose.     

固相法制备纳米Co3O4催化剂及其催化甲苯完全氧化性能

采用环境友好的固相法制备了高活性甲苯氧化Co3O4催化剂,通过与传统沉淀法和柠檬酸络合-燃烧法制备的Co3O4催化剂比较,固相合成法制备的Co3O4-SR催化剂在催化甲苯完全氧化反应中表现了很好的活性和稳定性,甲苯转化率为95%时的反应温度T95为230℃,反应60 h活性没有下降.通过XRD,Raman,FT-IR,XPS等手段对Co3O4催化剂的结构和表面性能进行了表征,结果表明固相法制备的Co3O4催化剂具有较多的表面缺陷,催化剂表面Co—O键较弱,具有较强的活化氧的能力,表现出突出的甲苯完全氧化的催化活性.     

溶剂热法合成不同形貌的Co3O4及其电容特性

采用溶剂热法以不同的钴盐在水-正丁醇体系中合成了不同形貌及尺寸的纳米Co3O4. 采用XRD和TEM对产物的物相和形貌进行表征. 结果表明, 通过改变反应体系中阴离子的种类, 可以控制产物Co3O4的形貌与晶粒尺寸. 通过循环伏安法、恒流充放电和交流阻抗法对Co3O4电极材料的电化学性能进行表征. 结果表明, Co3O4的形貌与晶粒尺寸对其电化学性能有显著影响. 在2 mol·L-1 KOH溶液中, 在-0.40 - 0.55 V (vs SCE)电位范围内, 由Co(NO3)2制备的球形Co3O4表现出更好的电容特性,单电极初始比容量达362.0 F·g-1, 经过400 次循环后比容量仍保持90%.     

超微粒CO3O4的合成与表征

本文用胶溶法合成了纳米级超微粒Co_3O_4,初步探讨了合成Co_3O_4超微粒的最佳实验条件,对产品的结构性能测试表明,所得超微粒子Co_3O_4粒度均匀,平均粒度为4.0nm.200℃热处理时,产品为无定形,在许多有机溶剂中具有良好的分散性和透明性;400℃热处理得到立方Co_3O_4纳米晶体,平均粒度为6.0nm,热稳定性好。     

Fe3O4 and gamma-Fe2O3 nanoparticles for the adsorption of Co2+ from aqueous solution

The adsorption of Co2+ ions from nitrate solutions using iron oxide nanoparticles of magnetite (Fe3O4) and maghemite (gamma-Fe2O3) has been studied. The adsorption of Co2+ ions on the surface of the particles was investigated under different conditions of oxide content, contact time, solution pH, and initial Co2+ ion concentration. It has been found that the equilibrium can be attained in less than 5 min. The maximum loading capacity of Fe3O4 and gamma-Fe2O3 nanoparticles is 5.8 x 10(-5) and 3.7 x 10(-5) mol m(-2), respectively, which are much higher than the previously studied, iron oxides and conventional ion exchange resins. Co2+ ions were also recovered by dilute nitric acid from the loaded gamma-Fe2O3 and Fe3O4 with an efficiency of 86 and 30%, respectively. That has been explained by the different mechanisms by including both the surface and structural loadings of Co2+ ions. The surface adsorption of Co2+ on Fe3O4 and gamma-Fe2O3 nanoparticles has been found to have the same mechanism of ion exchange reaction between Co2+ in the solution and proton bonded on the particle surface. The conditional equilibrium constants of surface adsorption of Co2+ on Fe3O4 and gamma-Fe2O3 nanoparticles have been determined to be log K=-3.3+/-0.3 and -3.1+/-0.2, respectively. The structural loading of Co2+ ions into Fe3O4 lattice has been found to be the ion exchange reaction between Co2+ and Fe2+ while that into gamma-Fe2O3 lattice to fill its vacancy. The effect of temperature on the adsorption of Co2+ was also investigated, and the value of enthalpy change was determined to be 19 kJ mol(-1).     

氧还原和析氧反应的双功能电催化剂--氮磷共掺碳负载四氧化三钴

金属-空气电池具备诸多优势,譬如绿色环保、能量转化率高、启动快速、能量密度高、使用寿命和干态存储时间长等.与燃料电池相比,金属-空气电池结构简单,放电电压平稳,成本低,但依然存在一些制约发展的问题,如阴极催化剂.阴极催化剂在金属-空气电池中发挥催化氧还原反应(oxygen reduction reaction, ORR)和析氧反应(oxygen evolution reac-tion, OER)的关键作用.铂及其合金常用作 ORR的单功能催化剂,而钌和铱等是目前 OER催化效率最高的,但 ORR活性很低,因此需要开发出一种廉价而又具备双功能催化作用的催化剂.单异原子掺杂的碳基催化剂的研究集中在 ORR催化性能上,而多异原子共掺碳最近有研究表明具有双催化氧的性质,如氮磷共掺碳.在这些氮磷共掺的碳架中,氮磷共掺物起着 OER催化作用,掺氮物为 ORR催化的活性位点,而掺磷物起着强化作用.异原子掺杂负载的钴基催化剂(如掺氮还原氧化石墨烯载 Co3O4)是近年来双功能催化剂研究的另一个热点.钴基催化剂有着催化 ORR和 OER的多价价态,然而其本身导电性能差,这一缺陷可通过杂化石墨化碳来弥补,石墨化碳有着优良的导电性能.据我们所知,目前仍没有关于氮磷共掺碳负载的 Co3O4双催化氧的研究.我们合成了氮磷共掺碳(NPC)负载的 Co3O4(Co3O4/NPC),并首次探索了其氧还原和析氧性能. Co3O4/NPC合成分两步进行.首先通过三聚氰胺与植酸之间的酯化或缩聚覆盖在导电炭黑颗粒表面,在保护气氛下焙烧得到 NPC,然后经溶剂热反应以及空气中氧化合成 Co3O4/NPC.催化剂的性能综合考虑了催化活性和稳定性两方面.采用线性扫描伏安法评估了 OER和 ORR的催化活性.对于 OER, Co3O4/NPC的起始电势是0.54 V (以饱和甘汞电极为参比电极),在0.80 V时电流密度达到21.95 mA/cm2,均优于 Co3O4/C和 NPC. Co3O4/NPC的高效 OER催化可归因于氮磷共掺物与 Co3O4之间的协同作用.对于 ORR, Co3O4/NPC的催化效率与商用 Pt/C相近,它们的扩散极限电流密度分别为–4.49和–4.76 mA/cm2(E =–0.80 V).在 ORR过程中, Co3O4起到主要的催化作用.采用计时电流(电流-时间)法评估了催化剂的稳定性.经6 h测定,对于 OER, Co3O4/NPC剩46%电流;而对于 ORR,剩95%电流.整体而言, Co3O4/NPC在 OER和 ORR中都表现出高的催化效率以及良好的稳定性.     

Boxes, helicates, and coordination polymers: a structural and magnetochemical investigation of the diverse coordination chemistry of simple pyridine-alcohol ligands

A structurally diverse array of polynuclear complexes has been identified and structurally characterized from the reaction of 6-methylpyridine-2-methanol (1) with a range of cobalt(II) salts under a variety of reaction conditions. A tetranuclear cubane, [Co4(1-H)4Cl4(H2O)3(CH3OH)], was isolated from the reaction of 1 with CoCl2.6H2O and NaOH in MeOH, and a tetranuclear double cubane, [Co4(1-H)6(NO3)2], was isolated from the reaction of 1 with Co(NO3)2.6H2O and NEt3 in MeOH. A bowl-shaped trinuclear complex, [Co3(1-H)3Cl3(dmso)], which features a triply bridging dmso ligand, assembled upon mixing 1 and CoCl2.6H2O in dmso. A 1-D coordination polymer, [Co(1)2(SO4)](infinity), where the sulfate ligands bridge "[Co(1)2]" units in a mu2:eta1 fashion to build up the polymer structure, was isolated from the reaction of 1 with CoSO4.7H2O. The reaction of the structurally related ligand 8-hydroxyquinaldine (2) with a mixture of CoCl2.6H2O and Co(OAc)2.4H2O lead to the formation of the tetranuclear double cubane, [Co4(2-H)6Cl2]. Temperature-dependent magnetic measurements have also been performed for these five complexes along with the hydrogen-bonded helicate [Co2(1)2(1-H)2]. The hydrogen bonds of the helicate mediate antiferromagnetic interactions between the cobalt(II) centers (J = -3.18(9) cm(-1), g = 2.25(2)). The sulfate bridging ligands of [Co(1)2(SO4)](infinity) are poor mediators of magnetic exchange. The Co(II) centers in the double-cubane complexes [Co4(1-H)6(NO3)2] and [Co4(2-H)6Cl2] are strongly antiferromagnetically coupled to each other at low temperature to give an S = 0 ground state. [Co4(1-H)4Cl4(H2O)3(MeOH)] exhibits rather complicated magnetic behavior; however, we did not observe any evidence for single-molecule magnetism as was seen for structurally related complexes.     

Pd掺杂对Co3O4催化CH4燃烧反应的影响:密度泛函理论计算

研究发现,Pd和Co3O4催化剂均可有效地催化甲烷燃烧反应,且Pd掺杂的Co3O4催化剂上甲烷反应活性优于单纯的Pd和Co3O4催化剂,可见两者存在明显的协同效应.然而由于Co3O4本身复杂的表面配位环境,相关理论模拟研究依然较少.同时,由于甲烷分子中C–H键有着非常高的键能,且该分子具有很高的对称性,导致C–H键活化往往是甲烷选择转化和完全燃烧反应中最困难的一步.由于Co3O4表面电子结构比较复杂,因此本文基于Co3O4(001)晶面的两种不同暴露面来构建和模拟Pd掺杂Co3O4表面Pd?O位点的甲烷反应活性.对于Co3O4(001)–A晶面,暴露面金属离子只有未饱和的八面体Coo,而(001)–B晶面,还有四面体Cot.由于Pd取代Cot后所形成的Pd/(001)–B面更不稳定,因而选择了较稳定的Pd替换Coo结构模型.基于第一性原理PBE+U计算的Pd/(001)表面甲烷活化能垒来探讨Pd掺杂对Co3O4表面催化活性的影响.计算表明,甲烷在Pd掺杂的(001)面上最低解离能垒为0.68 eV,明显低于在Co3O4(001)和(011)面的(分别为0.98和0.89 eV),表明Pd掺杂的(001)表面催化活性要远高于纯的Co3O4(001)和(011)表面.为了进一步理解Pd掺杂影响Co3O4表面甲烷反应活性的原因,我们计算了反应位点相关原子的Bader电荷.结果表明,当CH3δ–吸附于Pd/(001)–A面Pd位点时,Pd较(001)面上Co位点能从CH3δ–获得更多电子,这与Pd较Co有更强的氧化性一致.我们也对比了(001)–A,(001)–B,Pd/(001)–A和Pd/(001)–B在氧气分压为常压及不同温度下表面能的大小,并发现在与反应相关的温度区间(001)–A表面较(001)–B表面更为稳定,同样地Pd/(001)–A表面也较Pd/(001)–B表面更为稳定,且Pd/(001)–A表面与(001)–A表面稳定性差别不大,因此Pd单原子掺杂的(001)表面模型在热力学上较为稳定,且根据计算的能垒,(001)–A和Pd/(001)–A表面对甲烷活化的贡献最大.为了更好与实验结果对比,我们构建了简单的动力学模型,并计算了甲烷在Co3O4(001),(011)和1%,2%,3%Pd掺杂的Co3O4(001)表面的甲烷燃烧速率.计算表明即使较低量的Pd也可明显提高甲烷燃烧速率,与实验数据吻合较好,表明掺杂Pd显著增加Co3O4催化甲烷燃烧.     

Room temperature carbon monoxide oxidation over Pt/Co2SnO4 and Pt/(Co3O4+SnO2) catalysts

Catalytic activities of Pt/Co2SnO4, Pt/(Co3O4+SnO2), Pt/SnO2, and Pt/Co3O4 catalysts for CO oxidation were investigated by varying CO concentration at room temperature. Reaction rates over Pt/Co2SnO4 and Pt/Co3O4 catalysts were not affected from increase in CO concentration. This revised version was published online in June 2006 with corrections to the Cover Date.     

Thermal decomposition and cobalt species transformation of carbon nanotubes supported cobalt catalyst for Fischer-Tropsch synthesis

The effect of calcination condition on the cobalt species and Fischer-Tropsch synthesis (FTS) was studied. It was found that higher calcination temperature resulted in decreased FTS activities because CNTs were consumed by oxidation in air at temperature higher than 230°C. Cobalt species went through transformation from Co3O4 to metallic Co in Ar by autoreduction at temperature over 500°C. The autoreduction route might be Co3O4→CoO→Co or Co3O4→Co2C→Co. Reduction at temperature higher than 500°C also resulted in decreased FTS activities due to the methanation of CNTs in hydrogen.     

孔状Co_3O_4纳米片和纳米棒的选择性合成和表征(英文)

利用两步实验选择性合成孔状Co3O4纳米片和纳米棒:首先,以Co(NO3)2·6H2O,NaOH和不同量的NH4F为原料在120℃水热6h的条件下合成了Co(OH)2-Co3O4纳米片(S1)和Co(OH)F-Co3O4纳米棒(S2);然后将所得纳米片和纳米棒在400℃时加热2h即得到多孔的Co3O4纳米片和纳米棒。所得产物用X射线衍射(XRD)、场发射扫描电子显微镜(FE-SEM)和透射电子显微镜(TEM)进行了表征。此外电化学测试表明Co3O4纳米棒的电容量比Co3O4纳米片的更大。     

Reaction mechanism of aerobic oxidation of alcohols conducted on activated-carbon-supported cobalt oxide catalysts

Catalytic performances and the reaction mechanism of Co(3)O(4)/AC (AC=activated carbon) for aerobic oxidation of alcohols carried out in the liquid phase were investigated. Co(3)O(4)/AC shows a high activity for aerobic oxidation of benzyl alcohol, comparable to noble metal catalysts (e.g., Au/AC) even in the absence of additives or promoters (e.g., NaOH). Changing preparation conditions, such as treatment temperature and/or time, can affect the catalytic performances of Co(3)O(4)/AC, due to decomposition of surface groups of the carbon support. Careful studies show that low alcohol conversions are obtained with either Co(3)O(4) or AC alone, which indicates that the high conversion observed over the Co(3)O(4)/AC is due to a synergistic effect between Co(3)O(4) and AC. Parallel experiments using a high-surface-area covalent triazine framework or oxygen-inert carbon nitride as support for the Co(3)O(4) catalyst also show lower conversions, which suggest that the ability of AC (in Co(3)O(4)/AC) to activate molecular oxygen is essential for the reaction. FTIR and XPS spectra taken from catalysts before and after the reaction confirm that oxygen activation proceeds mainly on the carbon support. As a result, it can be assumed that the alcohol dehydrogenation step proceeds on the metal oxide, whereas the oxygen activation step occurs mainly on the carbon support.     

四氧化三钴负载金钯纳米催化剂催化消除甲苯和邻二甲苯

挥发性有机物(VOCs,例如甲苯和二甲苯)不仅危害人身健康,而且对大气环境造成严重污染.由于去除效率高、无二次污染以及耗能低等优点,催化氧化法被认为是消除VOCs的有效方法之一.该方法的关键是高效催化剂的研发.由于具有良好的低温催化氧化性能,过渡金属氧化物负载的贵金属催化剂备受关注.相比于单组分贵金属负载型催化剂,双组分贵金属负载型催化剂的催化活性、水热稳定性能和抗硫中毒性能均有显著提高.本文采用熔融盐法和聚乙烯醇保护的硼氢化钠还原法制备了八面体状Co3O4负载的AuPd(x(AuPdy)/Co3O4;AuPd负载量x=(0.18,0.47,0.97)wt%;Pd/Au摩尔比y=1.85,1.93,1.92)合金纳米催化剂.采用X射线衍射、扫描电子显微镜、透射电子显微镜、选区电子衍射、氢气程序升温还原、氧气程序升温脱附和X射线光电子衍射等技术对催化剂物化性质进行了表征.利用固定床微型反应器评价了催化剂对甲苯和邻二甲苯完全氧化反应的催化性能.研究结果表明,采用熔融盐法制得的Co3O4具有规整八面体形貌,棱长约为300 nm.AuPd合金纳米粒子均匀分布在Co3O4表面,粒径为2.7–3.2 nm.在所得催化剂中,0.96(AuPd1.92)/Co3O4催化剂对甲苯和邻二甲苯完全氧化反应表现出较高的催化活性.在空速为40000 mL/(g·h)时,甲苯和邻二甲苯转化率达到90%所需的温度分别为180和187 oC.我们认为0.96(AuPd1.92)/Co3O4催化剂较为优异的催化性能与AuPd纳米粒子和Co3O4之间的强相互作用和较高的吸附氧浓度有关.     

Co3O4/CeO2 CO氧化的原位红外光谱研究

采用沉淀氧化法制备了Co₃O₄/CeO₂催化剂。分别在干、湿条件下进行了一氧化碳氧化反应研究。运用FT-IR表征手段,在钴铈复合氧化物上进行了CO吸附及CO/O₂共吸附研究。结果表明,与纯的Co₃O₄样品相比,Co₃O₄/CeO₂具有明显的抗湿气能力。Co₃O₄/CeO₂催化剂在进行CO氧化时,表面形成了类碳酸盐物种。当环境温度低于453 K时,催化剂上类碳酸盐的生成与形成类碳酸盐物种后受热分解存在着动态平衡。当环境温度高于493 K,催化剂上生成的类碳酸盐物全部受热分解。氧化铈的加入提高了催化剂的抗湿气性能。较小粒径的Co₃O₄与CeO₂产生的强相互作用可使CeO₂向Co₃O₄提供氧,因而间接提供了CO氧化需要的氧。     

Mesoporous and nanowire Co3O4 as negative electrodes for rechargeable lithium batteries

The conversion reactions associated with mesoporous and nanowire Co(3)O(4) when used as negative electrodes in rechargeable lithium batteries have been investigated. Initially, Li is intercalated into Co(3)O(4) up to x approximately 1.5 Li in Li(x)Co(3)O(4). Thereafter, both materials form a nanocomposite of Co particles imbedded in Li(2)O, which on subsequent charge forms CoO. The capacities on cycling increase on initial cycles to values exceeding the theoretical value for Co(3)O(4) + 8 Li(+) + 8e(-) --> 4 Li(2)O + 3 Co, 890 mAhg(-1), and this is interpreted as due to charge storage in a polymer layer that forms on the high surface area of nanowire and mesoporous Co(3)O(4). After 15 cycles, the capacity decreases drastically for the nanowires due to formation of grains that are separated one from another by a thick polymer layer, leading to electrical isolation. In contrast, the mesoporous Co(3)O(4) losses its mesoporosity and forms a morphology similar to bulk Co(3)O(4) (Co particles imbedded in Li(2)O matrix) with which it exhibits a similar capacity on cycling. In contrast to mesoporous lithium intercalation compounds, which show superior capacity at high rates compared to bulk materials, mesoporosity does not seem to improve the capacity of conversion reactions on extended cycling. If, however, mesoporosity could be retained during the conversion reaction, then higher capacities could be obtained in such systems.     

还原气氛下金属－半导体催化体系Pt／MoO_3和Pt／Co_3O_4中电荷和物种传递特性的研究

利用程序升温电导法（ＴＰＥＣ）和程序升温还原法（ＴＰＲ），研究比较了还原气氛下Ｐｔ／ＭｏＯ_３和Ｐｔ／Ｃｏ_３Ｏ_４体系中不同类型的半导体氧化物和吸附氢之间电荷和物种交换的规律．发现微量Ｐｔ通过吸附解离Ｈ_２成为原子氢，在较低温度下大大加快ｎ型半导体氧化物ＭｏＯ_３和氢之间电子传递速度，显著地降低ＭｏＯ_３的还原温度，但在同样条件下却不能有效地活跃ｐ型半导体氧化物Ｃｏ_３Ｏ_４和氢之间的电子传递，因而不能明显地促进Ｃｏ_３Ｏ_４的还原．导致此现象的原因，可能与不同类型的半导体导电机构不同而引起的对氢的敏感程度不同有密切关系．