Enhanced activity for catalytic combustion of ethylene by the Pt nanoparticles confined in TiO2 nanotube with surface oxygen vacancy

Abstract VOCs, volatile organic compounds, which are mostly produced by the excessive emission of different industrial and commercial activities, pose a serious hazard to human health and primarily contribute to the creation of photochemical smog, which has a significant influence on air quality. The treatment of VOCs by catalytic oxidation at the lowest feasible temperature has been acknowledged as an efficient and cost-effective approach. Here, a novel catalyst with the platinum (Pt) nanoparticles confined in TiO2 nanotubes (TNT) by surface oxygen vacancy towards the catalytic combustion of ethylene has been prepared. Through the liquid-phase reduction strategy using sodium borohydride (NaBH4) as the reducing agent, the oxygen vacancies are effectively inserted onto the surface of TNT by regulating the reduction time, named as R-TNT. Subsequently, Pt was permitted to be trapped within R-TNT (Pt-in/R-TNT) via the vacuum assisted-impregnation method. The Pt nanoparticles confined in the TNT (Pt-in/TNT) could reduce the temperature down to about 175 °C for complete catalytic combustion of ethylene, a kind of VOCs, which was roughly 10 °C lower than the Pt nanoparticles loaded on TNT (Pt-out/TNT). More intriguing, the Pt-in/R-TNT displayed the highest catalytic activity and lowered the temperature by 20 °C. The X-ray photoelectron spectroscopy (XPS) and Ultraviolet–visible (UV–vis) measurements revealed that a saturation amount of oxygen vacancies were successfully introduced into TNT by reducing in NaBH4 solution. Based on the confinement effect of TNT, the formation of active oxygen species on the surface of TNT could further aggravate the electron density destitution inside TNT. Hence, the catalytic activity for Pt nanoparticles confined in R-TNT was significantly enhanced. A high-performance catalyst for removing VOCs is presented using an efficient confinement effect coupled with an electron modifier approach.