A hollow titanium oxynitride nanorod array as an electrode substrate prepared by the hot ammonia-induced Kirkendall effect

Abstract

The Kirkendall effect has been widely employed for the preparation of hollow nanostructures along with galvanic replacement and Ostwald ripening as a non-templating method. Despite many successful demonstrations for Kirkendall void formation, they have been mostly confined to the synthesis of hollow metal oxides and sulfides. In this work, we explored the feasibility of the Kirkendall effect for the preparation of a nitride compound in an effort to extend its peculiar merits, and discovered a new mechanism of Kirkendall void formation in the synthesis of hollow titanium oxynitride arrays by the nitridation of TiO 2 . Our in-depth study revealed that the reduction power of hot NH 3 played a crucial role in the formation of the Kirkendall void. When employed as an electrode substrate for supercapacitor applications, the hollow titanium oxynitride array showed a superior capacitive performance, which is ascribed to its high electrical conductivity and low density.

Chemical modification at and within nanopowders: Synthesis of core‐shell Al2O3@TiON nanopowders via nitriding nano‐(TiO2)0.43(Al2O3)0.57 powders in NH3

“…The bottom line is NPs remain but with completely different morphologies . Note that previous reports indicate that nitridation of TiO 2 can lead to formation of TiON hollow particles in support of the current observations …”

“…Thus, transition metal, silica and boron based compounds are relatively easy to nitride/reduce using NH 3 at temperatures ca. 1000°C . In contrast, alumina nitrides easily only above 1100°C .…”

“…A commercial TiO 2 was nitrided at 850°/6 h and 1000°C/3 h leading to materials with mass gains of 21 and 24 wt %, respectively coincident with SSAs unchanged at 850°C but reduced from 52 m 2 /g to 29 m 2 /g at 1000°C (see also ref. ). Thus, there is a tradeoff in rate of nitridation with loss of SSA = aggregation/partial sintering.…”

Nitrogen-Doped Carbon Nanocoil Array Integrated on Carbon Nanofiber Paper for Supercapacitor Electrodes

“…19 The electrochemical deposition was performed under the same threeelectrode system employed for the PPy deposition in a 0.1 M Ni(NO3)2 solution heated to 65 o C.…”

A Generalizable Top‐Down Nanostructuring Method of Bulk Oxides: Sequential Oxygen–Nitrogen Exchange Reaction

“…The Brunauer–Emmett–Teller (BET) surface areas of TiO 2 and TiO x N y were 8.7 and 27.4 m 2 g −1 , respectively, and the presence of mesopores/hollow voids in TiO x N y was also reflected in the pore size distribution (inset of Figure B). This observation revealed that porosity was introduced into TiO x N y during nitridation, which resulted from some of the oxygen vacancies created during nitridation merging into interior voids . To shed light on the local structural changes that occurred in bulk TiO 2 during nitridation, time‐resolved transmission electron microscopy (TEM) analysis was performed.…”