共查询到17条相似文献,搜索用时 187 毫秒
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分别以硼氢化钠和乙二醇为还原剂,经络合还原法制备了炭载钯(Pd/C)催化剂。透射电镜(TEM)和X射线粉末衍射谱(XRD)结果表明,以乙二醇为还原剂制备的Pd/C催化剂中Pd粒子具有较小的粒径、均匀的粒径分布和较大的相对结晶度,Pd粒子的平均粒径和相对结晶度分别为4.2±2 nm和1.88。电化学测试结果显示,以乙二醇为还原剂制备的Pd/C催化剂具有较大的电化学活性面积,对甲酸氧化表现出较高的电催化活性和稳定性。 相似文献
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通过微波辅助多元醇方法以XC-72碳黑作为基体材料制备了Pd/C材料,对其进行惰性气氛下热活化处理,制备了热活化Pd/C催化剂,并对不同温度制备的Pd/C催化剂的电催化甲酸氧化反应的性能进行了探究。在电化学测试中,热活化后的Pd/C催化剂的电催化活性和长时间运行稳定性都得到了显著提升。此外,在对热活化温度优化后,发现当热活化温度达到500℃时,所制备的Pd/C-500℃催化剂的甲酸电氧化活性和稳定性达到最佳水平。分析认为,催化性能的提升来源于Pd纳米颗粒的结晶性的提高,以及更强的金属载体的相互作用。 相似文献
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A new carbon-supported PdNi (PdNi/C) catalyst is prepared by a simple simultaneous reduction reaction with sodium borohydride
in glycol solution. The results show that the performance of PdNi/C catalyst for formic acid oxidation is greatly improved
compared with that of Pd/C. X-ray diffraction (XRD) results show that Ni exists in the catalyst both as NiO and as PdNi alloy.
The value of the apparent activation energy shows that the activity of formic acid oxidation on the PdNi/C is more sensitive
to temperature compared with Pd/C. 相似文献
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To improve the electrochemical performance of Pd‐based catalysts for formic acid oxidation, a carbon supported nanoporous PdNi catalyst is prepared by dealloying high‐Ni‐content PdNi alloy nanoparticles in acid solution. The structure of nanoporous PdNi/C catalyst is characterized by X‐ray diffraction, transmission electron microscopy and X‐ray photoelectron spectroscopy. The electrocatalytic results show that the activity of the nanoporous PdNi/C catalyst is higher than that of nonporous Pd/C catalyst. The results demonstrate that the carbon‐supported nanoporous PdNi catalyst has a potential for application in direct formic acid fuel cells. 相似文献
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Jae Ho Choi Soon Young Noh Sam Duck Han Soo Kyung Yoon Chang-Soo Lee Taek-Sung Hwang Young Woo Rhee 《Korean Journal of Chemical Engineering》2008,25(5):1026-1030
The oxidation of formic acid by the palladium catalysts supported on carbon with high surface area was investigated. Pd/C
catalysts were prepared by using the impregnation method. 30 wt% and 50 wt% Pd/C catalysts had a high BET surface area of
123.7 m2/g and 89.9 m2/g, respectively. The fuel cell performance was investigated by changing various parameters such as anode catalyst types,
oxidation gases and operating temperature. Pd/C anode catalysts had a significant effect on the direct formic acid fuel cell
(DFAFC) performance. DFAFC with Pd/C anode catalyst showed high open circuit potential (OCP) of about 0.84 V and high power
density at room temperature. The fuel cell with 50 wt% Pd/C anode catalyst using air as an oxidant showed the maximum power
density of 99 mW/cm2. On the other hand, a fuel cell with 50 wt% Pd/C anode catalyst using oxygen as an oxidant showed a maximum power density
of 163 mW/cm2 and the maximum current density of 590 mA/cm2 at 60 °C. 相似文献
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Pd catalyst supported on Vulcan XC‐72 carbon black was prepared by a modified polyol process. Its performance was compared with that of Pd/C catalyst prepared by impregnation reduction method by using NaBH4 as a reducing agent for formic acid electrooxidation. Their physical characterisations were tested by means of energy dispersive analysis of X‐ray, X‐ray diffraction and transmission electron micrographs. Their activities were presented by cyclic voltammetry and chronoamperometry. The results show that the particle sizes of Pd/C catalysts prepared by modified polyol process and impregnation reduction method are 3.9 and 7.9 nm, respectively. The size dispersion of the former is narrower and more homogeneous than that of the latter. However, both of Pd/C catalysts display the characteristic diffraction peaks of a Pd face‐centred cubic (f.c.c.) crystal structure. The results of electrochemical measurements present that the Pd/C catalyst prepared by modified polyol process has the higher electrocatalytic activity and stability for formic acid electrooxidation in comparison to the Pd/C one by impregnation reduction method due to the particle size effect, and its peak current density of CV and the current of chronoamperometric curve at 1,000 s reach 33.2 and 11.2 mA cm–2, respectively. 相似文献
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混酸法预处理了载体碳纳米管(CNTs),采用两步法制备PtPb/CNTs和PtB i/CNTs催化剂。以甲酸为研究对象,首次采用循环伏安法长时间连续性扫描的方法研究催化剂的抗CO中毒能力。研究发现,添加了Pb、B i金属后,增强了Pt/CNTs催化剂性能,如甲酸的起始氧化电位明显降低、氧化电流密度增大且抗毒性能增强。PtPb/CNTs、PtB i/CNTs催化甲酸的起始氧化电位都低于Pt/CNTs(0.099V),依次为-0.108和-0.004V(Vs.Ag/AgC l);在0.6V处,PtPb/CNTs、PtB i/CNTs催化氧化甲酸产生的电流密度都明显大于Pt/CNTs(0.79 mA/cm2),依次为3.10和1.77mA/cm2;PtPb/CNTs、PtB i/CNTs催化剂的寿命依次为Pt/CNTs催化剂的4倍和5倍。本文主要进行燃料电池电催化剂材料的研究,对于制造新型电催化剂有一定的探索作用。 相似文献
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Characterization and application of electrodeposited Pt, Pt/Pd, and Pd catalyst structures for direct formic acid micro fuel cells 总被引:1,自引:0,他引:1
In this work, we study the preparation, structural characterization, and electrocatalytic analysis of robust Pt and Pd-containing catalyst structures for silicon-based formic acid micro fuel cells. The catalyst structures studied were prepared and incorporated into the silicon fuel cells by a post CMOS-compatible process of electrodeposition, as opposed to the more common introduction of nanoparticle-based catalyst by ink painting. Robust, high surface area, catalyst structures consisting of pure Pt, pure Pd, and Pt/Pd = 1:1 were obtained. In addition, Pt/Pd catalyst structures were obtained via spontaneous deposition on the electrodeposited pure Pt structure. The catalyst structures were characterized electrochemically using cyclic voltammetry and chronoamperometry. All Pd-containing catalyst structures facilitate formic acid oxidation at the lower potentials and deliver higher oxidation currents compared to pure Pt catalyst structures. Fuel cells of these catalyst structures show that pure Pd catalyst structures on the anode exhibit the highest peak power density, i.e. as high as 28.0 mW/cm2. The MEMS compatible way of catalyst electrodeposition and integration presented here has yielded catalyst structures that are highly active towards formic acid oxidation and are sufficiently robust to be compatible with post-CMOS processing. 相似文献
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Sam Duck Han Jae Ho Choi Soon Young Noh Kunyik Park Soo Kyung Yoon Young Woo Rhee 《Korean Journal of Chemical Engineering》2009,26(4):1040-1046
Palladium particles supported on porous carbon of 20 and 50 nm pore diameters were prepared and applied to the direct formic
acid fuel cell (DFAFC). Four different anode catalysts with Pd loading of 30 and 50 wt% were synthesized by using impregnation
method and the cell performance was investigated with changing experimental variables such as anode catalyst loading, formic
acid concentration, operating temperature and oxidation gas. The BET surface areas of 20 nm, 30 wt% and 20 nm, 50 wt% Pd/porous
carbon anode catalysts were 135 and 90 m2/g, respectively. The electro-oxidation of formic acid was examined in terms of cell power density. Based on the same amount
of palladium loading with 1.2 or 2 mg/cm2, the porous carbon-supported palladium catalysts showed higher cell performance than unsupported palladium catalysts. The
20 nm, 50 wt% Pd/porous carbon anode catalyst generated the highest maximum power density of 75.8 mW/cm2 at 25 °C. Also, the Pd/porous carbon anode catalyst showed less deactivation at the high formic acid concentrations. When
the formic acid concentration was increased from 3 to 9 M, the maximum power density was decreased from 75.8 to 40.7 mW/cm2 at 25 °C. Due to the high activity of Pd/porous carbon catalyst, the cell operating temperature has less effect on DFAFC
performance. 相似文献