Pd Decoration with Synergistic High Oxygen Mobility Boosts Hydrogen Sensing Performance at Low Working Temperature on WO₃ Nanosheet

Abstract

Pd-based materials have received remarkable attention and exhibit excellent H2 sensing performance due to their superior hydrogen storage and catalysis behavior. However, the synergistic effects originated from the decoration of Pd on a metal oxide support to boost the sensing performance are ambiguous, and the deep investigation of metal support interaction (MSI) on the H2 sensing mechanism is still unclear. Here, the model material of Pd nanoparticle-decorated WO3 nanosheet is synthesized, and individual fine structures can be achieved by treating it at different temperatures. Notably, the Pd-WO3-300 materials display superior H2 sensing performance at a low working temperature (110 °C), with a superior sensing response (R a/R g = 40.63 to 10 ppm), high sensing selectivity, and anti-interference ability. DFT calculations and detailed structural investigations confirm that the moderate MSI facilitates the generation of high mobility surface O2 – (ad) species and a proper ratio of surface Pd0–Pd2+ species, which can significantly boost the desorption of intermediate PdH x species at low temperatures and contribute to enhanced sensing performance. Our work illustrates the effect of MSI on sensing performance and provides insight into the design of advanced sensing materials.

Delafossite CuGaO2-Based Chemiresistive Sensor for Sensitive and Selective Detection of Dimethyl Disulfide

“…We have implemented the PTM approach as a physical sensitization strategy to boost the response of the CuGaO 2 sensor to ppb-level DMDS . Unlike conventional chemical sensitization techniques involving either morphology control or noble metal decoration, ,,− the PTM method has nothing to do with the sensor material but only cyclically heats up and cools down the sensor under a certain heating waveform. A high temperature (HT) of 320 °C (heating voltage of 6 V, period of 5 s) and low temperature (LT) of 20 °C (heating voltage of 0.1 V, period of 5 s) with a rectangular waveform have been applied in this work, as schematically shown in the inset of Figure a.…”

“…Proton transfer reaction mass spectrometer (PTR-MS) analysis of the outlet gas suggests that CuGaO 2 could effectively decompose/oxidize the DMDS into small-molecule sulfur compounds like CH 3 S. The present CuGaO 2 sensor exhibits good long-term stability (dropping ∼13.8% after 5 months) and outstanding moisture resistance performance, which enables it to operate under a high humid (90% RH) air background with a slight decline (about 13.0%) of response in comparison with dry air. Furthermore, as an alternative to the conventional sensitization approach of noble metal decoration via sophisticated synthesis method, ,, pulsed temperature modulation (PTM) via periodically heating up and cooling down the sensor has been employed to boost the DMDS response (25 times enhancement for 10 ppm DMDS), via decoupling the conflicting role of temperature on target molecule adsorption, redox reaction, and resistance reading. , We could achieve a high response (3.2) to 100 ppb DMDS and a low LoD of 3.3 ppb by PTM-operated CuGaO 2 sensor in comparison with the state-of-the-art DMDS sensors. ,,, In addition, we have developed a smart DMDS monitoring system (comprising selective CuGaO 2 sensor, reading electronics, Bluetooth module, and App on mobile phone), which enables to accurately and selectively monitor DMDS vapor under ambient humid air background, even with the presence of four kinds of interference VOCs, demonstrating the practical application potential of the present CuGaO 2 sensor in environmental DMDS odor monitoring.…”

“…In comparison with bulky analyzing equipment such as gas chromatography–mass spectroscopy, ,, metal oxide semiconductor (MOS)-based chemiresistive sensors, ,− featured by low cost, long lifetime, and easy microminiaturization and integration, act as the ideal candidate for developing smart Internet of Things-enabled sensing electronics. Recently, various types of MOS-type DMDS sensors have been reported.…”

Pd Nanoparticles Decorated Hollow TiO2 Nanospheres for Highly Sensitive and Selective UV-Assisted Hydrogen Gas Sensors

“…Moreover, it increases the electron density of metallic Pd causing an activation. According to the literature, the formed type of the physisorbed or chemisorbed oxygen species depends on the working temperature. , normalO 2 ( a d ) → O 2 false( a d false) − .25em ( ≤ 150 °C ) O 2 false( a d false) − → O ( a d ) − .25em ( 150 − 400 °C ) O ( a d ) − → O lattice 2 − .25em ( ≥ 500 °C ) …”

Influence of the Pd Oxidation State in PdNi Thin Films on Surface Acoustic Wave Hydrogen Sensing Performance

“…In the context of the growing low-carbon economy (LCE), hydrogen (H 2 ) energy has gained widespread usage in various applications, such as hydrogen fuel cell vehicles and hydrogen chemical industry. − However, hydrogen exhibits notable attributes, including rapid diffusion (0.61 cm 2 /s), low ignition energy (∼0.2 mJ), and a wide flammability range in air (4–75 v/v%). − These attributes lead to safety risks in H 2 production, transportation, and utilization. To ensure the safe utilization of H 2 , there is a high demand for highly sensitive H 2 sensors with excellent long-term stability. , Depending on the underlying hydrogen sensing mechanisms, H 2 sensors can be categorized into different types, such as mechanical or electrochemical change-based, resistance-based, thermal-based, acoustically assisted, catalytic activity-based, and optically assisted sensors. − Among these, surface acoustic wave (SAW) hydrogen sensors have emerged as a promising technology due to their remarkable advantages in terms of response speed, sensitivity, and low-power consumption. , …”