Fabrication and characterization of TiO2-NTs based hollow carbon fibers/carbon film composite electrode with NiOx decorated for capacitive application

Abstract This work designs a novel structure of TiO 2 nanotubes (TiO 2 -NTs) based hollow carbon nanofibers (HCFs)/carbon film (CF) composite electrode with NiO x decorated for capacitive deionization application. The TiO 2 -NTs array is obtained through anode oxidation method on the titanium substrate, while the HCFs/CF is synthesized by thermal decomposition of a mixture of C 6 H 12 O 6 and Ni(CH 3 COO) 2 ·4H 2 O inside the nanochannels and over the caps of TiO 2 -NTs array, then followed by carbonization and HNO 3 activation. The nickel possesses multi-functional effects during the synthesis process as carbon catalyst (Ni(II)), molecule binder (NiTi) and pseudo-capacitance supplier (NiO x ). FE-SEM, XRD, Raman spectroscopy and water contact angle measurement reveal a uniform carbon distribution, favorable nickel dispersion, high stability and ideal hydrophilicity for this structure. With the addition of C 6 H 12 O 6 and Ni(Ac) 2 ·4H 2 O controlled at 10% (wt) and 2% (wt), respectively, a composite electrode with specific capacitance of 244.9 F·g −1 , high oxygen evolution potential of 2.15 V and low water contact angle of 41.77° is obtained as well as minimum polarization impedance and efficient capacitive ability, which exhibits promising applications for practical employment.