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Effects of acid etching on the structure of PtNi catalyst and total exposed active sites
Author(s) -
Yang Bin,
Zhao Yanting,
Fang Liudang
Publication year - 2020
Publication title -
surface and interface analysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.52
H-Index - 90
eISSN - 1096-9918
pISSN - 0142-2421
DOI - 10.1002/sia.6787
Subject(s) - x ray photoelectron spectroscopy , cyclic voltammetry , catalysis , scanning electron microscope , analytical chemistry (journal) , etching (microfabrication) , hydrogen , chemistry , binding energy , electrode , electrochemistry , materials science , inorganic chemistry , chemical engineering , layer (electronics) , nanotechnology , organic chemistry , composite material , physics , nuclear physics , engineering
The integration technology of hydrogen preparation–hydrogen storage not only can utilize hydrogen energy efficiently but also can improve the selectivity of the electrode maximally. In the present work, the structure and composition of the PtNi catalyst was characterized by X‐ray diffraction (XRD); and its electrochemical properties, morphology, and surface binding energy were analyzed by cyclic voltammetry (CV) and linear scanning voltammetry (LSV), scanning electron microscopy equipped with energy‐dispersive spectrometry (SEM‐EDS), and X‐ray photoelectron spectroscopy (XPS), respectively. The effects of different acid etching treatments (e.g., etching time, etchant concentration, and etching temperature) on the structure and surface active sites were investigated by the orthogonal experiment. The experimental results reveal that after etching with 0.5 mol/L of perchloric acid for 0.5 h at 60°C, the electrode weight loss of the PtNi catalyst is mainly attributed to the large loss of Ni atoms in film layer. This results in the reduced alloy phase in film layer and the appearance of Pt characteristic diffraction peak. The relative content of Pt on the surface of the film electrode increases significantly, and the total number of active sites also increases correspondingly. The binding energy of Pt4f 7/2 decreases by 0.19 eV, and the number of active sites involved in hydrogen release decreases, indicative of the reduced promotion effect of the PtNi catalyst on hydrogen release.