One‐Dimensional TiO ₂ Nanorod Arrays via Hydrothermal Method for Rapid and Stable Hydrogen Gas Sensing

ABSTRACT One‐dimensional titanium dioxide (TiO 2 ) nanorod arrays are hydrothermally synthesized and explored as an efficient platform for high‐performance hydrogen (H 2 ) sensing. X‐ray diffraction confirms highly crystalline rutile TiO 2 , while FTIR verifies characteristic Ti─O─Ti bonding. FESEM reveals densely aligned nanorods with high aspect ratios, offering a large surface area and direct electron transport pathways. The chemiresistive sensor exhibits excellent performance over 50–2000 ppm H 2 , achieving ∼1400% response at 2000 ppm and ∼250% at 50 ppm. Rapid response and recovery times (∼20 and ∼18 s) and strong repeatability (<±5% variation) are observed. The sensor maintains stable operation under varying humidity (10%–80% RH), retaining >500% response even at 80% RH, and operates efficiently at low temperatures (40°C–60°C). The enhanced performance is attributed to oxygen vacancy‐mediated surface reactivity, efficient charge transport, and accelerated gas diffusion within the porous nanorod network. These findings demonstrate that hydrothermally grown rutile TiO 2 nanorods provide a scalable, low‐cost, and high‐performance solution for next‐generation hydrogen sensing in environmental monitoring and industrial safety.