Hydrothermal synthesis and gas sensing properties of lamellar Nickel Titanate

Abstract

Synthesizing pure nickel titanate using the hydrothermal method has posed a significant challenge. In this study, single phase lamellar structured nickel titanate were successfully synthesized via the hydrothermal method. X-ray diffraction spectroscopy (XRD), field emission scanning electron microscopy (FE-SEM), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy (RAMAN), high-resolution transmission electron microscopy (HRTEM), Fourier-transform infrared spectroscopy (FT-IR), and Brunauer-Emmett-Teller (BET) methods were employed to investigated the effects of varying hydrothermal durations and pH values on the sample's structure and gas-sensing performance. Results indicates that hydrothermal duration of 20 h and pH of 13 yielded sample showed single ilmenite phase, and highly sensitive ammonia (NH₃) detection capability. At room temperature, the sample exhibited a remarkable response of 17.92 k% to 500 ppm NH₃, with a response time of 13.8 s and a recovery time of 2.4 s, and a theoretical detection limit of 3.7 ppm. The exceptional sensing performance can be attributed to lamellar structure that well-exposed surface of the pore, which can absorb more oxygen molecules and provide additional active sites for redox reactions between target gas molecules and adsorbed oxygen. The outcome of this work might provide strategy for the design of novel sensing materials.