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NH3gas sensors operating at room temperature, consisting of Ag nanoparticles decorated β-AgVO3nanorods (Ag/β-AgVO3NRs), were fabricated viaa facile hydrothermal method without the need for a template. The surface characteristics and compositions of Ag/β-AgVO3NRs were analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Ag nanoparticles, ranging in diameter from approximately 20 to 40 nm, were dispersed on the surface of monoclinic β-AgVO3NRs with diameters ranging from 50 to 105 nm and lengths from 0.3 to 1.3 μm. The NH3gas sensing properties of Ag/β-AgVO3NRs were studied under both dry air and humid conditions at room temperature. Comparative analysis demonstrated that the Ag/β-AgVO3NRs exhibited a strong response to NH3gas under 70% relative humidity (RH) at room temperature compared to α-AgVO3NRs. Specifically, the response of the Ag/β-AgVO3NRs to 5 ppm NH3increased by 2.25 times as the RH varied from 20% to 80% at room temperature. This enhanced response was attributed to the effects of formation of nanoheterojunctions, nano-metallic Ag activity and the conductivity of NH4+and OH−ions induced by the presence of humidity. The room temperature NH3gas sensors based on Ag/β-AgVO3NRs demonstrated strong responses to low NH3concentrations, high selectivity, good reproducibility, and long-term stability, and show promise for the development of low-power and cost-effective NH3gas sensors for practical applications even under high humidity.

Conifer-like TiSnO2nanorods mixed metal oxide was synthesized viathe one-pot polyol method utilizing ethylene glycol (EG), poly(diallyldimethylammonium chloride) (PDDA), tin(ii) chloride dihydrate (SnCl2·2H2O), and titanium(iv)-ethylhexanoate (TE) as precursor materials, aimed at room temperature H2S gas sensing. The effects of polyol duration time and capping agent concentration (PDDA) were examined to explore the morphological, structural, and gas-sensing characteristics, as well as to propose potential growth mechanisms of conifer-like TiSnO2nanorods mixed metal oxide. The morphology and composition of the synthesized TiSnO2mixed metal oxide were carried out employing scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), and X-ray diffractometry (XRD). The experimental findings demonstrated a significant influence of polyol duration time and PDDA concentration on the morphological evolution of the synthesized TiSnO2mixed metal oxide structures. Comparative gas-sensing analysis indicated that the conifer-like TiSnO2nanorods mixed metal oxide exhibited the highest response (2.45%) towards H2S gas at a concentration of 1 ppm, along with a low detection limit (0.20 ppm) and good linearity (R2= 0.9865) within the range of 1–15 ppm of H2S gas at room temperature.