Integrated Coaxial Graphene-Based Yarn with Multidimensional Architecture for Self-Powered Photoelectrochemical Methane Sensor

Effective and reliable methane detection is essential and critical to environment protection, and life and property safety. However, how to enable a sensing platform for methane monitoring with high sensitivity and stability, and meanwhile with excellent structural flexibility and ease of integration remains a significant challenge. Herein, an integrated coaxial yarnshaped selfpowered photoelectrochemical methane sensor was successfully designed and constructed by employing wet-spun graphene (G) fiber as the inner electrode, G-based mixeddimensional materials hybridization as the outer electrode, and a polymer gel coated inbetween as the electrolyte separator. The high surface roughness and significant transmittance of obtained device enabled effective adsorption capacity and essential light penetration. A continuous and thin gel electrolyte interlayer in the sensor and singlewalled carbon nanotube (SWNT)-bridged interconnected conductive network in a multidimensional hybrid facilitated fast ion/electron transport. Ascribed to above structural merits, the resulting sensor delivered a wide linear range from 0.05% to 0.47% and a low detection limit of 0.02%, while maintaining rapid response (0.3 s), outstanding selectivity and perfect working performance during bending. This work provides useful guidelines for designing and fabricating photoelectrochemical sensors toward highly sensitive gas detection.