Planar quasi-fuel-cell structure gas sensor based on laser-induced graphene electrode for fast H2 detection

Tuned LIG microstructures via laser parameters for high-efficiency H 2 sensing. • Developed a LIG-based flexible electrochemical hydrogen sensor with a response/recovery time of 2.6 s/3.2 s. • The sensor exhibits high selectivity, flexibility, linearity and stability. • Employing MnO 2 as the cathode material enables reliable hydrogen detection under oxygen-free conditions. Laser-induced graphene (LIG) technology has become an ideal strategy for fabricating electrode materials due to its ability to produce flexible graphene substrates rapidly and scalably. In this work, a planar flexible electrochemical hydrogen gas sensor with a quasi-fuel-cell structure is designed, which is based on a composite membrane electrode of LIG/Nafion/MnO 2 . By adjusting laser parameters, a porous laser-induced graphene (LIGP) substrate with high specific surface area and high graphitization is controllably fabricated. On this basis, an anode with low Pt loading is constructed. In particular, the arrayed gas diffusion channels enable hydrogen to diffuse and distribute directly and efficiently to the electrode surface. Manganese dioxide (MnO 2 ) serves as the cathode active material for the reduction reaction, replacing the kinetically sluggish oxygen reduction reaction (ORR) in conventional systems, thereby eliminating the dependence on oxygen. The optimized LIGP sensor exhibits response and recovery times of merely 2.6 s and 3.2 s, respectively, with a sensitivity up to 5.98 nA/ppm and a limit of detection (LOD) of 0.83 ppm, alongside excellent selectivity, long-term stability, and mechanical flexibility. This study integrates laser processing technology, electrode material optimization, and device structural innovation to achieve low cost and high sensing performance, providing a new route for the development and mass fabrication of flexible hydrogen sensors. Download: Download high-res image (298KB) Download: Download full-size image