Ethylene glycol + H2O + Na2CO3: A new electrolyte system to anodically grow Ni-Ti-O nanopores on NiTi alloy

Abstract

We report on a new electrolyte system to fabricate Ni-Ti-O nanopores with small diameter and high Ni content by anodizing nearly equiatomic NiTi alloy. In the electrolyte composed of ethylene glycol, 5 vol% H2O, and 0.23–0.9 wt% Na2CO3, uniform Ni-Ti-O nanopores with diameter of about 25 nm and Ni/Ti atomic ratio exceeding 0.30 can be anodically grown on the NiTi alloy under proper applied voltage (20–40 V). The small diameter (high specific surface area) and high Ni content enable the nanopores promising in electrochemical energy storage, electrocatalysis, gas/bio-sensing, and other emerging fields.