Highly photoactive sensor based on NiO modified TiO2 porous film for diethyl ether

In this work, NiO modified TiO2 nanocomposites were prepared by a simple milling-anneal method and fabricated onto the device by the technology of screen printing. The phase structures and surface morphologies of the as-prepared samples were characterized by scanning electron microscopy (SEM), X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and high-resolution transmission electron microscopy (HR-TEM), respectively. The photocurrent measurements were performed in a high-throughput platform. The results revealed the TiO2 film was non-sensitive to diethyl ether (DEE) under UV-light excitation. In contrast, the NiO modified TiO2 films exhibited higher sensitivity to DEE under the same condition. It indicated that NiO made DEE easily adsorb and be immobilized on its surface owing to the selectivity of the surface sites for gas molecules. Therefore, in the presence of the p-n junction formed between NiO and TiO2, NiO as a hole acceptor resulted in the photooxidation of DEE while TiO2 acted as a hole donor, which gave guidance to select and design nanostructure-based sensors for the specific gas.