화학공학소재연구정보센터
Journal of the Electrochemical Society, Vol.154, No.6, F111-F121, 2007
A study of anodically grown hydroxide films on an amorphous Ni78Si8B14 alloy
Films grown on amorphous Ni78Si8B14 alloy and on polycrystalline Ni by polarization in 1 M KOH solution were analyzed by X-ray photoelectron spectroscopy (XPS) and scanning tunneling spectroscopy (STS). XPS investigations showed that the films formed on both the amorphous Ni78Si8B14 alloy and polycrystalline Ni at open-circuit potential and after polarization at 0.4 V-RHE consist of Ni(OH)(2), while the films formed after polarization at 0.5 V-RHE consist of NiOOH. No traces of B or Si in the uppermost of the hydroxide films produced on the amorphous Ni78Si8B14 alloy were found. STS showed that all films formed on the amorphous Ni78Si8B14 had more n-type semiconductor character than those formed on polycrystalline Ni. Electrochemical investigations indicated that the amorphous Ni78Si8B14 alloy is a better electrocatalyst for the oxygen evolution reaction than polycrystalline Ni. We discuss whether this can be attributed to an enhanced electron density on the Ni sites in the alloy leading to an increase in the tunneling probability of the electrons on the surface film. This can subsequently enhance its catalytic action towards the oxygen evolution reaction. (c) 2007 The Electrochemical Society.