Hydrogen Oxidation and Evolution Reaction Kinetics on Platinum: Acid vs Alkaline Electrolytes
Hydrogen Oxidation and Evolution Reaction Kinetics on Platinum: Acid vs Alkaline Electrolytes
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DOI：
10.1149/1.3483106
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发表时间：
2010-01-01
影响因子：
3.9
通讯作者：
Shao-Horn, Yang
中科院分区：
文献类型：
--
作者：
Sheng, Wenchao;Gasteiger, Hubert A.;Shao-Horn, Yang
采用旋转圆盘电极（RDE）研究了多晶铂[Pt（pc）]和高比表面积碳载铂纳米颗粒（Pt/C）在0.1 M KOH中的氢氧化反应（HOR）和析氢反应（HER）动力学。在对交流阻抗法测得的非补偿溶液电阻和HOR分支中氢的质量传递进行修正后，采用传递系数α = 0.5将动力学电流密度拟合为Butler-Volmer方程，得到了Pt（pc）和Pt/C上的HOR/HER交换电流密度，并对碱性溶液中的HOR/HER机理进行了讨论。与碱性溶液中Pt电极上的HOR/HER速率不同，0.1 M HClO（4）中Pt电极上的HOR/HER速率完全受到氢扩散的限制，这使得HOR/HER动力学的定量不可能通过常规RDE测量。基于80 ℃下HOR/HER的比交换电流密度的氢阳极性能的模拟说明，除了阴极上的氧还原反应电池电压损失之外，对于低铂负载，较慢的HOR动力学预计会导致碱性燃料电池中显著的阳极电势损失（在0.05 mg（Pt）/cm（阳极）（2）和1.5 A/cm（阳极）（2）下> 130 mV），与质子交换膜燃料电池的报道相反。(C)2010年电化学学会。[DOI：10.1149/1.3483106]保留所有权利。
The kinetics of the hydrogen oxidation reaction (HOR) and hydrogen evolution reaction (HER) on polycrystalline platinum [Pt(pc)] and high surface area carbon-supported platinum nanoparticles (Pt/C) were studied in 0.1 M KOH using rotating disk electrode (RDE) measurements. After corrections of noncompensated solution resistance from ac impedance spectroscopy and of hydrogen mass transport in the HOR branch, the kinetic current densities were fitted to the Butler-Volmer equation using a transfer coefficient of alpha = 0.5, from which HOR/HER exchange current densities on Pt(pc) and Pt/C were obtained, and the HOR/HER mechanisms in alkaline solution were discussed. Unlike the HOR/HER rates on Pt electrodes in alkaline solution, the HOR/HER rates on a Pt electrode in 0.1 M HClO(4) were limited entirely by hydrogen diffusion, which renders the quantification of the HOR/HER kinetics impossible by conventional RDE measurements. The simulation of the hydrogen anode performance based on the specific exchange current densities of the HOR/HER at 80 degrees C illustrates that in addition to the oxygen reduction reaction cell voltage loss on the cathode, the slow HOR kinetics are projected to cause significant anode potential losses in alkaline fuel cells for low platinum loadings (> 130 mV at 0.05 mg(Pt)/cm(anode)(2) and 1.5 A/cm(anode)(2)), contrary to what is reported for proton exchange membrane fuel cells. (C) 2010 The Electrochemical Society. [DOI: 10.1149/1.3483106] All rights reserved.