Ultra-sensitive and selective methanol sensor based on crystallinity-engineered LaFeO₃ porous nanoarchitectures

Abstract

Ultra-sensitive detection of methanol is critical for industrial safety, environmental monitoring, and chemical process control. This work reports a novel crystallinity-porosity dual engineering strategy for developing high-performance perovskite ferrite gas sensors with exceptional methanol detection capabilities. Through precisely controlled synthesis conditions (2 °C/min heating rate), we fabricated LaFeO₃ (LFO) porous nanomaterials exhibiting both superior crystallinity and optimal mesoporous architecture. The resulting sensor demonstrates unprecedented performance, including ultrahigh sensitivity (S=300–100 ppm methanol), rapid response/recovery kinetics (23 s/25 s), wide dynamic range (1–1000 ppm), and low optimal operating temperature (150 °C), enabled by crystallinity-induced reduction of carrier density for efficient resistance modulation and three-dimensional mesoporous networks promoting gas diffusion. Density functional theory calculations confirm strong chemisorption at Fe sites (adsorption energy=−0.694 eV) with significant bandgap modulation (ΔE_g=0.95 eV), while the sensor maintains excellent reproducibility (RSD=3.2 %), long-term stability (>95 % response retention over 56 days), and humidity resistance (152 ± 6.3 response at 70 % RH). These findings establish a new paradigm for designing advanced gas sensors through simultaneous optimization of crystallinity and porosity in perovskite materials, offering both fundamental insights into structure-property relationships and practical solutions for industrial methanol detection applications.