UV-illumination room-temperature gas sensing activity of carbon-doped ZnO microspheres

Carbon-doped ZnO microspheres were prepared through a facile hydrothermal process. The characterizations for the physicochemical properties of prepared samples under different calcination temperatures were carried out on X-ray diffraction analysis, scanning electron microscopy, X-ray photoelectron spectroscopy, UV–vis diffuse reflectance spectra, Raman spectroscopy and photocurrent spectra. C-doped ZnO under 500°C calcination exhibited the superior UV-activated room-temperature gas sensing activity for the detection of ethanol. The result of transient photovoltage suggested that the presence of sp2 carbon-type structures could improve the separation extent and restrain the recombination of the photoinduced electron–hole pairs, which increase the number of photoinduced oxygen ions on the surface of C-doped ZnO and enhancing of gas sensing activity.