Catalytic lanthanum ions (La3+), beneficial for fast dissociative adsorption of hydrogen on its surface, were chosen and introduced into SnO2 nanofibers with different atomic molar ratio to Sn (AMR: 0.5%, 1.0% and 3%) via electrospinning and calcination technique. The sensitivity of La-SnO2 metastable solid solution nanofibers (LSMSSNs) for H-2 detection is 9.9 against 100 ppm H-2 at 300 degrees C, which is 2.5 times and 1.6 times higher than that of SnO2 nanofibers and La2O3@SnO2 p-n heterojunction nanofibers (LSPNHNs), respectively. More importantly, LSMSSNs achieved both rapid response and recovery behavior of similar to 1s, long range detectable linearity from 1000 to 25,000 p.m. against H-2 and good selectivity towards ethanol, toluene, carbon monoxide and butane, which is very useful for the practical application. A plausible sensing mechanism based on p-type La3+ doping has been established and the relationship with La2O3@SnO2 p-n heterojunction has been investigated. This work provides a basis for understanding and optimizing the high sensitive metal oxide based gas sensors. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.