Cyanogel-Transformed Porous Palladium and Iron Framework Intermixed with rGO for Wearable Hydrogen Sensing.

Wearable hydrogen (H) sensing is necessary to monitor the H leakage in its transportation and storage, of which ppm-concentration detection limit and fast response at room temperature are highly desired. Here, a wearable H sensing working at room temperature is developed with palladium and iron framework intermixed with reduced graphene oxide (rGO//Pd-Fe FW), which is synthesized by combined Pd-Fe cyanogel immobilized with graphene oxide as precursor and in situ reduction. As-prepared rGO//Pd-Fe FW is observed with porous FW structure composed of interconnected Pd-Fe nanoparticles, in which rGO is evenly intermixed. Beneficially, rGO//Pd-Fe FW exhibits 2 ppm low detection limit and 2 s fast response (1 v/v% H) at room temperature. Such excellent H sensing performance may be attributed to the synergistic effect of the optimized Pd-Fe FW's catalytic activity, boosted electron transfers between Pd hydride and rGO, and enriched adsorption sites over porous FW's surface. Practically, the perceptron learning algorithm combined with principal component analysis is conducted to identify the H leakage, and the wearable H sensing devices are built by integrating rGO//Pd-Fe FW over the paper and flexible printed circuit board with reliable sensing responses.