Structure and hydrogen evolution performance of nano-porous PtCu/C membrane catalysts
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摘要: 采用离子束溅射(Ion Beam Sputtering, IBS)与Pt、Cu移动双靶技术,结合真空退火及酸蚀处理等后处理工艺,制备出PtCu/C薄膜催化剂。采用高分辨透射电镜(HRTEM & STEM)、原子力显微镜测试(AFM)、X射线衍射(XRD)测试薄膜催化剂的表面形貌及组织结构。通过循环伏安法(CV)和线性扫描伏安法(LSV)测试薄膜催化剂的电化学析氢性能。结果表明,经过真空退火(400 ℃保温1 h)及酸蚀处理(1 mol/L HNO3,50 ℃,120 h)后的薄膜催化剂出现类蜂窝状纳米多孔结构,其电化学析氢交换电流密度达到0.004 27 A/cm2,相较于未后处理样品的铂载量降低8.77%,催化性能提升20.62%。Abstract: PtCu/C membrane catalysts were prepared by ion beam sputtering (IBS) with moving bimetallic Pt and Cu targets; they were post-processed by vacuum annealing in combination with acid etching. High resolution transmission electron microscopy (HRTEM & STEM) and atomic force microscope (AFM) were employed to characterize the surface morphology of post-processed samples; the alloying degree of Pt and Cu was determined by the X-ray diffraction (XRD). Through cyclic voltammetry (CV) and linear sweep voltammetry (LSV), the electrochemical hydrogen evolution properties of the PtCu/C membrane catalysts were investigated. The results indicated that the PtCu/C membrane catalyst annealed at 400 ℃ and etched by HNO3 exhibits honeycomb nano-porous structure; the loading of Pt is reduced by about 8.77%, whereas the catalytic activity is enhanced by about 20.62%, in comparison compared with the original PtCu/C membrane catalyst.
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Key words:
- ion beam sputtering /
- PtCu/C /
- membrane /
- post-processing /
- catalytic activity
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表 1 薄膜镀制参数
Table 1 Parameters for Ion Beam Sputtering (IBS)
Distance of movement d/mm Time t/s Screen voltageV/kV Beam currentI/mA Acceleration voltageV/kV Cleaning 0 300 0.8 70 200 Sputtering 20-50 600 2.6 70 140 表 2 样品后处理参数
Table 2 post-Processing conditions of samples
Sample Annealing temperature t/℃ Etching time t/h a - - b 400 - c - 120 d 400 120 表 3 样品a、d及Pt/C金属载量及i0值
Table 3 Metal loadings in the membrane and i0 values of various samples
Sample Pt/(mg·cm-2) Cu/(mg·cm-2) Pt/Cu(mol ratio) i0/(A·cm-2) a 0.057 0.051 0.36 0.00354 Pt/C 0.138 - - 0.00390 d 0.052 0.023 0.72 0.00427 表 4 AFM检测的高度参数
Table 4 Height parameters for various samples
Sample Sq /nm Ssk Sku Sp /nm Sv /nm Sz /nm Sa /nm a 0.52 1.04 9.14 6.54 2.07 8.61 0.40 d 10.90 0.14 2.71 37.50 30.80 68.30 8.76 -
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