Porous Pd–Sn Alloy Nanotube-Based Chemiresistor for Highly Stable and Sensitive H₂ Detection

Abstract

While H2 is indispensable as a green fuel source, it is highly flammable and explosive. Because it is difficult to detect due to its lack of odor and color, a solution for proper monitoring of H2 leakage is essential to ensure safe handling. To this end, we have successfully fabricated hollow Pd–Sn alloy nanotubes (NTs) with a Brunauer–Emmett–Teller surface area of 223.0 m2/g through electrospinning and a subsequent etching method, which is the first demonstration of synthesizing Pd-based hollow alloy nanofibers with ultrafine grain sizes. We found that the alloying of Pd with Sn could effectively prevent degradation of the sensing performance upon the α–β phase transition during hydrogen detection. Besides, the highly porous structure with smaller nanograins offered more exposed active sites and higher gas accessibility to bulk materials. The resultant Pd–Sn NTs exhibited excellent sensitivity toward H2 (0.00005–3%). Notably, the limit of detection of 0.0001% is an outstanding achievement on H2 sensing among state-of-the-art H2 sensors. Moreover, when exposed to a high concentration of H2 (3%), Pd–Sn NTs showed excellent cycling stability with a standard deviation of 0.07% and a sensitivity of 9.27%. These obtained sensing results indicate that Pd–Sn NTs can be used as a highly sensitive and stable H2 gas sensor at room temperature (25 °C).

Facile Synthesis of Co3O4/CoMoO4 Heterostructure Nanosheets for Enhanced Acetone Detection

“…The fabrication of sensors is reported by our previous study . Air and varying concentrations of target gas were injected into the gas-sensing chamber based on 10 min air and 10 min target gas as a complete cycle.…”

“…The fabrication of sensors is reported by our previous study. 23 Air and varying concentrations of target gas were injected into the gas-sensing chamber based on 10 min air and 10 min target gas as a complete cycle. The response of sensors was calculated as R gas /R air , where R gas and R air are the resistances in target gas and ambient condition, respectively.…”

Multilevel Self-Assembly of Block Copolymers and Polymer Colloids for a Transparent and Sensitive Gas Sensor Platform

“…This is due to the transition from the resistance increase mode (ΔR > 0) to the resistance decrease mode (ΔR < 0). 23,55 Under an ambient condition, not only H 2 but also O 2 molecules are adsorbed at the Pd surface to form partially oxidized PdO states. The formation of PdO states also brings about the reduction of conductivity.…”

“…Noticeably, in the dilute environmental condition of H 2 concentration below 0.3%, micromesh and nonpatterned films exhibit higher sensing performances compared to the hierarchical mesh and nanomesh. This is due to the transition from the resistance increase mode (Δ R > 0) to the resistance decrease mode (Δ R < 0). , Under an ambient condition, not only H 2 but also O 2 molecules are adsorbed at the Pd surface to form partially oxidized PdO states. The formation of PdO states also brings about the reduction of conductivity.…”

Intermetallic Pd–Sn Nanoparticles on Supports with High Metal Loading Facilitated by the Metal–Metal Bond for High-Performance Cooperative Catalysis

“…The calcination atmosphere (air vs nitrogen) is critical to induce a strong metal−support interaction (SMSI) 21 by creating different intermetallic Pd−Sn oxides/metals. Calcined materials under static air (Pd−Sn−g-C 3 N 4 −air) consist of many sub-5 nm particles along with a few big particles in the range of [10][11][12][13][14][15][16][17][18][19][20]. The lattice fringe fitting of these big particles suggests an intermetallic Pd−Sn alloy structure along with separated metal/metal oxides or mixed oxides (Figures 3A and S19).…”