Enhanced activity of CuOy/TNTs doped by CeOx for catalytic ozonation of 1,2-dichloroethane at normal temperatures: Performance and catalytic mechanism

Abstract

Achieving efficient and stable catalysts with chlorine resistance is of great importance for chlorinated volatile organic compounds (CVOCs) degradation. This study developed catalysts containing abundant CeOCu bonds anchored on titanium nanotubes (TNTs) to form strong electronic metal–metal interaction (EMMI) coordination structure for efficiently catalytic ozonation of 1,2-dichloroethane (1,2-DCE). The occurrence of EMMI resulted in the formation of electron-poor/rich centers and a high proportion of weak-acidity sites over Ce-Cu/TNTs catalysts. Among various catalysts, 1Ce1Cu/TNTs exhibited the optimum catalytic performance with 92.5 % of 1,2-DCE conversion and 85.4 % of CO2 selectivity, the long-term stability of 24 h and the good water resistance to 50 % relative humidity (RH). Importantly, the XPS results and DFT calculations suggested Ce drove the Cl atom off Cu species, thus alleviating the chloridion deposit on Cu sites, accelerating the migration of chlorine and offering more redox sites for O3 activation. Electron paramagnetic resonance (EPR) and radical quenching tests identified that •OH was a key reactive oxygen species to achieve efficient degradation of 1,2-DCE. The possible reaction pathways for the catalytic ozonation of 1,2-DCE included three parts, including O3 activation, 1,2-DCE preliminary degradation and deep oxidation, which obeyed the L-H mechanism.