A one-pot synthesis of a monolithic Cu₂O/Cu catalyst for efficient ozone decomposition

Nowadays, it is necessary and challenging to prepare monolithic catalysts, which are ready for use, preventing the tedious and complicated integration procedure of the powder materials onto a porous substrate. Herein, Cu₂O nanoparticles are successfully synthesized onto a porous Cu foam in one pot via the surface oxidation, coordination and precipitation reactions in a NH₄OH and HCl solution, and the optimum synthesis conditions are a NH₃ : HCl ratio of 1 : 0.9, oxidation temperature of 80 °C and time of 18 h. The obtained Cu₂O/Cu catalyst (mostly <100 nm) shows a highly active O₃ decomposition performance with >98% and >80% conversion efficiency in dry and 90% relative humidity air for >10 h at an O₃ concentration of 20 ppm and a gas hourly space velocity of 12 500 h^-1. The high efficiency can be attributed to the porous Cu foam providing a large contact area, abundant crystal defects in the nanometer-sized Cu₂O materials serving as the active sites, and also to the Schottky barrier formed in the Cu₂O/Cu interface facilitating the electron transfer for O₃ degradation. All these results show the potency of the easily fabricated monolithic Cu₂O/Cu catalyst for the highly efficient O₃ contaminant removal.