Synthesis, semiconductor characteristics and gas-sensing selectivity for cerium-doped neodymium vanadate nanorods

Abstract

Ce-doped NdVO4 nanorods (NRs) were synthesized via a one-step hydrothermal method by using edetate disodium (EDTA) as a chelating agent. CexNd1-xVO4 NRs with square section are assigned to the zircon-type tetragonal structure, and the growth direction for NRs is along the (200) plane. Cerium in CexNd1-xVO4 NRs is identified as substitutional dopant. Gas sensors based on CexNd1-xVO4 NRs exhibit that the types of semiconductors transfer from n, to p and n-type (n-p-n) with the amount of Ce. The surface for Ce0.2Nd0.8VO4 NRs is with positive charge by Zeta potentials measurement, confirming that it corresponds to p-type semiconductor. XPS data demonstrates that the quantity for Nd0 and V4+ as active sites on the surface for Ce0.2Nd0.8VO4 NRs increases by Ce doping, leading to increase in the quantity of adsorbed oxygen (O2−ads). According to the big dipole moment of acetone, Ce0.2Nd0.8VO4 NRs as p-type semiconductor with high O2−ads content interacts readily with acetone at Nd0 and V4+ sites during redox reaction. A gas sensor based on Ce0.2Nd0.8VO4 NRs towards acetone gas shows distinct selectivity and a wide detecting linear range to acetone from 10 to 1000 ppm (R2 = 0.98) at low operating temperature (108 °C).