Plasmon-assisted facile selective gaseous isopropanol dehydrogenation over Ag nanocubes

Abstract

In the current research, monodisperse Ag nanocubes are synthesized and characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), field-emission transmittance electron microscopy (FE-TEM), X-ray photoelectron spectroscopy (XPS), and UV-vis photospectrometry. It is seen that isopropanol can be dehydrogenated to acetone over Ag nanocubes in high selectivity at near-room temperatures. Light illumination leads to an increase in the isopropanol dehydrogenation efficiency without decreasing the selectivity. The effects of reaction temperatures, light wavelengths, light intensities, and sizes of the Ag nanocubes on the catalytic yields are investigated in detail. The result reveals that plasmonic heating has a low contribution to the light-induced increase of the catalytic activity, which could be ascribed to a plasmonic non-thermal effect. It is seen that the dehydrogenation activity is dependent on α-hydrogen activation. As compared to methanol, ethanol, and N-propanol, isopropanol presents the highest light-induced catalytic activity because of the most active α-hydrogens. It is considered that the hot electron transfer from the Ag nanocubes to molecular O₂ accelerates oxygen activation for isopropanol dehydrogenation.