A CeCoO_x Core/Nb₂O₅@TiO₂ Double‐Shell Nanocage Catalyst Demonstrates High Activity and Water Resistance for Catalytic Combustion of o‐Dichlorobenzene

Abstract

A series of catalysts with different core-shell structures has been successfully prepared by a hydrothermal method. They consisted of CeCoO x @TiO 2 (single shell), CeCoO x @Nb 2 O 5 (single shell) and CeCoO x @Nb 2 O 5 @TiO 2 (double shell) core-shell nanocages and CeCoO x nanocages, in which CeCoO x was the core and TiO 2 and Nb 2 O 5 were shells. The influence of the core-shell structure on the catalytic performance of o-dichlorobenzene was investigated by activity, water-resistance, and thermal stability tests as well as catalyst characterization. The temperatures corresponding to 90 % conversion of o-dichlorobenzene (T 90 ) of CeCoO x , CeCoO x @TiO 2 , CeCoO x @Nb 2 O 5 , and CeCoO x @Nb 2 O 5 @TiO 2 catalysts were 415, 383, 362 and 367°C, respectively. CeCoO x @Nb 2 O 5 exhibited excellent catalytic activity, mainly owing to the special core-shell structure, large specific surface area, abundant activity of Co 3 + , Ce 3 + , Nb 5 + , strong reducibility, and more active oxygen vacancies. It can be seen that the Nb 2 O 5 coating can greatly improve the catalytic activity of the catalyst. In addition, due to the protective effect of the TiO 2 shell on CeCoO x , CeCoO x @Nb 2 O 5 @TiO 2 catalysts exhibited outstanding thermal and hydrothermal stability for 20 hours. The T 90 of CeCoO x @Nb 2 O 5 @TiO 2 was slightly lower than that of CeCoO x @Nb 2 O 5 , but it had higher stability and hydrothermal stability. Furthermore, possible reaction pathways involving the Mars-van-Krevelen (MvK) and Langmuir-Hinshelwood (LÀ H) models were deduced based on studies of the temperature-programmed desorption of O 2 (O 2 -TPD), X-ray photoelectron spectroscopy (XPS), and in situ diffuse reflectance FTIR spectroscopy (DRIFTS) characterization.

Fabrication of a multi-dimensional CoFeOx catalyst for the efficient catalytic oxidation elimination of o-dichlorobenzene

“…In addition, transition metal oxides have good resistance to chlorine poisoning and are widely used in the catalytic combustion of CVOCs. 13–16 The structure of spinel oxide allows doping of other metal elements in the preparation of catalytic materials, and the synergistic effect between these metals improves the catalytic performance. The specific surface area of the catalyst is an essential factor in the performance of the catalyst.…”