Hydrogen Sensors from Composites of Ultra-small Bimetallic Nanoparticles and Porous Ion-Exchange Polymers

Hydrogen (H2) is a flammable gas, and even tiny leaks of H2 must be detected for safety. However, the detection of low levels (below ppm) of H2 in air still remains an unmet challenge. Herein, we present a facile synthesis of bimetallic nanoparticles (BM-NPs) by using porous ion-exchange polymers in order to develop superior H2 sensors. The porous ion-exchange polymers enable the versatile fabrication of ultra-small BM-NPs on various supports. In particular, PdPt NPs derived from our method show excellent H2-sensing performances at room temperature in air, with an ultra-low detection limit (0.4 ppm), as a result of the synergistic effect of PdPt NPs on H2 sensing. We further developed a wireless H2-sensing system by combining PdPt NPs with radio-frequency communication. Our method can not only pave a new way in the field of H2 sensors but also be easily extended to the fabrication of various ultra-small BM-NPs for diverse applications needed the superior activity of BM-NPs. © 2020 Elsevier Inc.Bimetallic nanoparticles (BM-NPs) have attracted much attention in catalysis, sensing, and electronics as a result of their ultra-high activity for surface reactions. For reliable utilization of BM-NPs in various applications, robust synthetic methods for the creation of non-aggregated functional BM-NPs with diameters less than a few nanometers are needed. Herein, we present functional assemblies of ultra-small BM-NPs produced within high-stability porous ion-exchange polymers. Specifically, PdPt NPs can be readily produced with precision dimensional control down to 1 nm. These PdPt NPs with porous polymers display superior hydrogen (H2)-sensing properties at room temperature in air. We achieve an ultra-low limit of detection (H2 0.4 ppm), thereby confirming the outstanding sensing performance of the PdPt NPs. We further demonstrate a wireless H2-sensing system by combining porous polymer-templated PdPt NPs with a radio-frequency identification (RFID) system, which enables the