Deciphering the external electric field effect on lattice oxygen migration over monolithic CoCuOx for toluene degradation.

Electrically driven catalysis has been considered as an advanced technique for volatile organic compound degradation. Nevertheless, a definitive understanding of the non-thermal contributions of the electric field effect within this catalytic system remains to be elucidated. In this investigation, a cobalt substituted copper foam monolithic catalyst (CoCuOx) achieves the most efficient toluene degradation compared to Co3O4/CuOx and CuOx, at ultra-low temperatures in an electric field (T93 = 178 ℃) for the efficiency in charge separation and electron transfer over a homogeneous surface. The characterization results show that the partial electron transfer between Cu and Co cations by bridged oxygen species is boosted by the electric field effect. The oxygen transient experiment and theoretical calculations illustrate that the electrically driven catalytic reaction conforms to the typical MvK mechanism, and the electric field accelerates migration and supplementary of lattice oxygen species, resulting in an increase in oxygen vacancy concentration. This intensified migration behaviour of lattice oxygen may constitute the functional core of the electric field effect. Furthermore, an alternative reaction route directly attacking the bonds of aromatic hydrogens (C-H) and benzene rings is also induced by additional energy input, electron transfer, and lattice oxygen activation. This work offers insights into the impact of electric field on the toluene catalytic degradation, which might guide the electrically driven catalysis for VOCs treatment in non-hyperthermic environments.