We review the synthesis, characterization, and applications of one-dimensional palladium-based nanostructures and provide perspectives on future directions in this field.

We present a unique three-dimensional palladium (Pd)-decorated crumpled reduced graphene oxide ball (Pd-CGB) nanocomposite for hydrogen (H 2 ) detection in air at room temperature. Pd-CGB nanocomposites were synthesized using a rapid continuous flame aerosol technique. Graphene oxide reduction and metal decoration occurred simultaneously in a high-temperature reducing jet (HTRJ) process to produce Pd nanoparticles that were below 5 nm in average size and uniformly dispersed in the crumpled graphene structure. The sensors made from these nanocomposites were sensitive over a wide range of H 2 concentrations (0.0025−2%) with response value, response time, and recovery time of 14.8%, 73 s, and 126 s, respectively, at 2% H 2 . Moreover, they were sensitive to H 2 in both dry and humid conditions. The sensors were stable and recoverable after 20 cycles at 2% H 2 with no degradation associated with volume expansion of Pd. Unlike two-step methods for fabricating Pd-decorated graphene sensors, the HTRJ process enables single-step formation of Pd-and other metal-decorated graphene nanocomposites with great potential for creating various gas sensors by simple drop-casting onto low-cost electrodes.