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高催化活性、低成本、良好工艺兼容性以及高稳定性的析氢催化剂是实现一体化光电化学水解制氢器件的关键, 然而传统的贵金属催化剂由于储量稀缺、成本高昂而严重限制了光电化学水解制氢器件的产业化进程. 本文在室温下通过湿法化学合成法制备了高催化活性、成本低廉以及工艺兼容性好的非金属非晶三硫化钼析氢催化剂, 并研究了不同催化剂滴涂量对其催化活性以及串联制氢器件制氢性能的影响. 结果表明, 存在最优化非晶三硫化钼催化剂滴涂量以获得最佳催化活性(10 mA/cm2电流密度对应电势达260 mV vs. RHE(可逆氢电极), 塔菲尔斜率达68 mV/dec), 其粗糙表面以及多孔结构可获得更大的电化学接触面积以促进析氢反应. 进一步将其作为光阴极应用于串联制氢器件, 可有效降低过电势损失和提高光生电流密度输出, 与光阳极结合有望提高制氢效率. 相似文献
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纳米TiO2光催化降解有机污染物研究与应用新进展 总被引:12,自引:2,他引:12
在参考近两年国内外大量文献基础上,对纳米TiO2的光催化机理、催化剂性能的改进方法和影响催化剂性能的环境因素进行了评述和探讨;介绍了催化剂表面声光能辐射处理以及电场、微波、超声波助催化技术等新型增效、助效技术的研究进展;并综述了最近两年纳米TiO2在水环境污染物去除、小空间空气处理和材料表面抗菌抗蚀自洁净方面的应用研究新进展。 相似文献
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甲酸具有来源广、成本低、质量储氢密度高等优势,成为潜在的化学储氢载体之一,然而,现在甲酸脱氢技术存在催化剂易失活、产物CO浓度高等挑战。开发高性能甲酸脱氢催化剂并实现脱氢产物的选择性调控是推动甲酸制氢技术长效发展的关键。本文提出以生物炭为载体、含钯双金属合金为活性组分,构筑Pd-M/BC(M=Cu, Ni, Fe, Co;BC为生物炭)催化剂,实现甲酸低温、高转化率及低CO选择性制氢。考察了不同热解温度生物炭载体、活性组分对甲酸脱氢性能的影响,结果表明,150°C、0.006 mL/min甲酸流率下可得到最低的CO选择性(1.31%)与高甲酸转化率(74.88%),该研究可为Pd-M/BC催化甲酸脱氢技术的发展提供理论指导。 相似文献
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本文研究TiO2以及金属(Cu、Ni)掺杂TiO2催化剂水解制氢的两种不同析氢反应机理,计算了不同反应过程催化反应活化能,同时考察了系列催化剂电子激发态的催化活性.结果表明:催化剂电子激发态的催化活性增强,说明光照有助于降低反应的活化能,提高催化剂的活性.金属(Cu、Ni)掺杂TiO2有助于降低水解制氢反应的活化能,且Cu的掺杂催化效果更明显,这与实验报道的结果一致. 相似文献
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本文系统研究了臭氧修饰对(001)主导晶面锐钛矿型TiO2光催化剂降解甲苯性能的影响. 利用自行搭建的光催化VOCs降解装置对催化剂光降解甲苯的性能进行了测试. 通过多种表征手段,结合原位DRIFTS和DFT计算研究了臭氧表面修饰及甲苯吸附和降解机理. 结果表明,用臭氧进行表面修饰可以显著提高(001)主导晶面TiO2光催化降解甲苯的性能. (001)晶面上丰富的5c-Ti不饱和配位是臭氧分子的吸附位点,其解离后形成的Ti-O键与H2O分子结合,在表面生成大量孤立的Ti5c-OH. Ti5c-OH 是甲苯分子的吸附位,它的形成显著提高了对甲苯分子的吸附能力. 在光照下Ti5c-OH与光生空穴结合能形成·OH自由基. 通过臭氧解离产生的O2也可以与光生电子结合形成超氧自由基. 这些具有强氧化性活性自由基的形成促进了对气相甲苯的光催化降解速率. 相似文献
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The production of hydrogen via steam reforming of ethanol (SRE) is favourable for the use of hydrogen as an alternative fuel. Co–Mo6S8 possesses high activity and stability for SRE to sustainably produce hydrogen. The competition among reaction pathways related to C–H, O–H, C–C, C–O cleavage and H2 formation was studied. The adsorption and reaction of related intermediates in the ESR reaction pathway are described. The results indicated that the most feasible route for the decomposition of ethanol catalysed by Co–Mo6S8 is CH3CH2OH*→CH3CH2O*→CH3CHO*→CH2CHO*→CHCHO*→CHCO*→CH*+CO*. The CH* can be decomposed into C*+H*, and CO* can be oxidised via the redox mechanism of the water gas shift (WGS) reaction. Thus the final products are CO2 and H2. The present result may help people to design an SRE catalyst, which has the ability to break C–C to form CO and H2, then CO react with H2O in the WGS reaction generating CO2 and H2. 相似文献
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通过高分辨的扫描隧道显微术研究并比较了金红石型TiO2(110)-(1×1)和锐钛矿型TiO2(001)-(1×4)两种表面的活性位点. 在金红石型TiO2(110)-(1×1)表面, 观察到氧空位缺陷是O2和CO2分子的活性吸附位点,而五配位的Ti原子是水分子和甲醇分子的光催化反应活性位点.在锐钛矿型TiO2(001)-(1×4)表面,观察到完全氧化的表面,Ti原子更可能是六配位的,H2O和O2分子均不易在这些Ti原子上吸附.经还原后表面出现富Ti的缺陷位点, 这些缺陷位点对H2O和O2分子表现出明显的活性. 锐钛矿型TiO2(001)-(1×4)表面的吸附和反应活性并不具有很高的活性,某种程度上其表现出的活性似乎低于金红石型TiO2(110)-(1×1)表面. 相似文献
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本文利用循环伏安法和电化学原位红外光谱的联用,研究了Pt(111)和Pt膜电极在CO2饱和的酸性溶液中氢析出和CO2还原的竞争. 发现:(i)在pH>2的溶液中,主要反应是氢析出,界面pH值随着氢析出突然增加;(ii)通过红外光谱检测,COad是CO2还原过程中唯一的吸附中间体;(iii)COad生成速率随着欠电位沉积氢(UPD-H)覆盖的增加而增大,并在氢析出的起始电位达到最大值;(iv)在氢析出时,COad的减少与CO2吸附和还原所必需的的中间产物(Had)有限的可用位点和停留时间相关. 相似文献
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研究了通过有机金属化学气相沉积技术及单源分子前躯体方法制备的Ni/Al2O3纳米复合材料的氢吸附(存储). 在冷壁的有机金属化学气相沉积反应器中,通过降解Ni(acac)2粉末基底上的[H2Al(OtBu)]2制备的Ni/Al2O3纳米复合材料. 通过X射线粉末衍射、扫描电镜、透射电镜以及能量色散型X射线荧光光谱等技术表征该复合材料. 采用自制Sievert's设备研究该复合材料的氢吸附(存储),可以储存约2.9%(重量比)的氢. 相似文献
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MoO3 and Mo samples containing copper were treated with different hydrocarbon/hydrogen gas mixtures. The formation of Mo2C was followed by X-ray photoelectron spectroscopy (XPS). Spectra taken in the Mo 3d, C 1s, O 1s, Cu 2p and Cu KLL regions demonstrated that the treatment with the hydrocarbon/hydrogen gas mixtures led to the formation of Mo2C. From the comparison of the effects of various hydrocarbons on the XP spectra of Mo 3d we can state that the reduction of MoO3 starts at the lowest temperature for C2H6/H2 (600 K) followed by CH4/H2 (700 K) and C4H10/H2 (723 K). Binding energies of Mo 3d5/2 characteristic for Mo2C are measured in the range of 227.7-228.0 eV. These values were attained at 900 K for CH4/H2, at 800 K for C2H6/H2 and at 873 K for C4H10/H2. Addition of copper to MoO3 catalyzed its reduction and promoted the carburization process. 相似文献
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High roughness and a greater number of defects were created by lithium niobate (LN; LiNbO3) processes such as traditional grinding and mechanical polishing (MP), should be decreased for manufacturing LN device. Therefore, an alternative process for gaining defect-free and smooth surface is needed. Chemical mechanical planarization (CMP) is suitable method in the LN process because it uses a combination approach consisting of chemical and mechanical effects. First of all, we investigated the LN CMP process using commercial slurry by changing various process conditions such as down pressure and relative velocity. However, the LN CMP process time using commercial slurry was long to gain a smooth surface because of lower material removal rate (MRR). So, to improve the material removal rate (MRR), the effects of additives such as oxidizer (hydrogen peroxide; H2O2) and complexing agent (citric acid; C6H8O7) in a potassium hydroxide (KOH) based slurry, were investigated. The manufactured slurry consisting of H2O2-citric acid in the KOH based slurry shows that the MRR of the H2O2 at 2 wt% and the citric acid at 0.06 M was higher than the MRR for other conditions. 相似文献
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Luciano A. Leal Wiliam F. da Cunha Luiz F. Roncaratti Geraldo M. e Silva 《Molecular physics》2016,114(3-4):440-445
ABSTRACTBased on ab initio calculations, our research group has built an analytical ground-state potential energy surface (PES) for hydrogen peroxide– noble gas (Ng) interactions, such as H2O2–He, H2O2–Ne, H2O2–Ar, H2O2–Kr, and H2O2–Xe complexes. From this PES, it was verified that the Ng presence does not affect the equilibrium values of the H2O2 dihedral angles. This happens because the H2O2 intramolecular barriers have much higher energies than the atom–bond interaction within these complexes. From this point of view, it is indeed reasonable to consider the H2O2 system as a rigid rotor, frozen at its equilibrium configuration. We present in this work the torsional motion for the H2O2 isolated system, the vibration–rotation energy levels and spectroscopic constants for hydrogen peroxide–noble gas by using the aforementioned PES. The predicted H2O2 torsional motions are in good agreement with both theoretical and experimental results available in the literature. Regarding H2O2–Ng ro-vibrational energies and spectroscopic constants, it is the first time that these calculations are presented in the literature. The current theoretical predictions are expected to be useful in the future experimental investigations. 相似文献