Amorphous Pt-Decorated NiFe2O4 Nanorods for Acetone Sensing

The decoration of less agglomerated hierarchical semiconducting metal oxides with noble metals is a widely used strategy to obtain high-performance gas sensors. Beyond conventional approaches, we synthesized amorphous Pt-decorated NiFe2O4 nanorods as sensing materials by using a temperature-controlled one-step impregnation method. This method is characterized by its simplicity and green, energy-efficient, and economical use of noble metals. The Pt-decorated NiFe2O4 nanorods show unusual resistance behavior in air, and their operating temperature-resistance curve exhibits two transitions. This phenomenon results from the enhanced chemisorption of oxygen molecules compared to pristine NiFe2O4, which was proven by the operating temperature-dependent resistance behavior in N-2. The synergistic effects between the amorphous noble metal and less agglomerated structure lead to significantly improved sensing performance to acetone, especially the 5 wt % Pt-decorated NiFe2O4. It shows a 37-fold increase in gas response, a lower optimal operating temperature, and enhanced selectivity compared to its counterpart. This research offers an efficient method for designing noble metal-decorated, high-performance metal oxide sensing materials and provides insights into the baseline resistance of oxygen chemisorption onto the surface sensing materials.