Efficient post-plasma catalytic degradation of toluene via series of Co–Cu/TiO₂ catalysts

Abstract

Volatile organic compounds (VOCs) represent a very important class of pollutants that causes serious health effects. There is an urgent requirement to establish efficient technologies that can reduce and control VOCs. Non-thermal plasma (NTP) is an emerging technology that can decompose low concentration VOCs. However, the low efficiency and high power cost are major hindrances in its commercialization. In this work, Co–Cu with TiO₂ support catalysts are prepared by using the deposition precipitation method and utilized in post-plasma catalysis for the efficient degradation of toluene selected as a model VOC. The synergistic effect of Co–Cu/TiO₂ with different Co/Cu molar ratios along with pure Co/TiO₂ and Cu/TiO₂ catalysts are studied for their catalytic activity. Results showed that the degradation efficiency of toluene for the control experiments (plasma-alone) increased from 10 to 85% with the increase in input power from 11 to 44 W. In comparison, a significant improvement in the degradation efficiency is achieved with post-plasma catalysis owing to better physicochemical properties such as particle surface area and microstructures of the Co–Cu/TiO₂ catalysts. The Co₅₀–Cu₅₀/TiO₂ exhibited highest degradation efficiency of toluene, i.e. 55% being 5.5 times higher than control at lowest input power of 11 W while 96% at the highest input power of 44 W, attributed to interaction of Co and Cu species, adsorbed oxygen content, and redox properties by exchange of pairs Co⁺³/Co⁺² and Cu⁺²/Co⁺³. In summary, the post-plasma catalysis integrated with Co₅₀–Cu₅₀/TiO₂ catalyst rendered optimal outcomes in terms of power consumption and degradation of VOCs, envisioning commercial viability.

Graphical abstract