Ultrasensitive and Wide‐Range Flexible Hydrogen Sensor Based on Pd Nanoparticles Decorated Ultrathin SnO₂ Film

Abstract

Highly sensitive and reliable hydrogen detection is prerequisite for the large‐scale implementation of green energy hydrogen. It remains a tough challenge to get a highly selective H2 sensor to low concentration H2 gas with low working temperature. In this work, high performance flexible hydrogen sensor using ultrathin SnO2 film decorated by Pd nanoparticles (NPs) on polyimide (PI) was developed based on versatile atomic layer deposition (ALD) and cluster beam deposition (CBD). The influence of Pd NPs loading amount and operating temperature on the performance of hydrogen sensors was studied. The sensors obtain an extremely high response over 20000 to 30 ppm H2 at the relatively low operating temperature of 75–125 °C. The Pd NPs@SnO2/PI sensor achieves a wide detection range of 0.1‐5000 ppm with the limit of detection (LOD) of 100 ppb at 125 °C. A low LOD of 250 ppb can still be achieved at room temperature. The sensors also exhibit outstanding sensing selectivity for hydrogen over interfering gases and excellent mechanical resistance after 2000 bending cycles. The mechanism for improved sensing performance of ALD ultrathin film with CBD‐derived noble metal NPs decoration may be a feasible strategy for the construction of highly sensitive, selective, and flexible hydrogen sensors.

Ultrathin Boundary-Less SnO2 Films with Surface-Activated Two-Dimensional Nanograins Enable Fast and Sensitive Hydrogen Gas Sensing

“…24,25 The 2D electrical transportation behaviors are dominated by grain boundaries, which lead to an inefficient signal transduction from the surface chemical process to the bulk conductivity. Various new studies have been reported in the literature to enhance the gas reception and transduction performance of the SnO 2 -based ultrathin films, e.g., by doping, 26 noble metal decoration, 27 and UV illumination. 28 However, there is still a general lack of effective strategies to enhance the intrinsic sensing performance of the SnO 2 -based films, which is a major obstacle to their further performance optimization and practical applications.…”

“…However, the defective (101) surfaces of the ultrathin SnO 2 can be steadily passivated by the undesirable surface adsorbents (mostly the OH groups) under ambient conditions. − The OH groups will dominate the surface electron states and hinder the gas–solid interaction, leading to unsatisfied gas sensing performance. , Besides that, the majority of the nanocrystalline 2D oxides consist of numerous nanograins with in-plane grain sizes down to a few nanometers. , The 2D electrical transportation behaviors are dominated by grain boundaries, which lead to an inefficient signal transduction from the surface chemical process to the bulk conductivity. Various new studies have been reported in the literature to enhance the gas reception and transduction performance of the SnO 2 -based ultrathin films, e.g., by doping, noble metal decoration, and UV illumination . However, there is still a general lack of effective strategies to enhance the intrinsic sensing performance of the SnO 2 -based films, which is a major obstacle to their further performance optimization and practical applications.…”

“…As shown in Figure 4e, the devices showed an optimum sensor response (R a /R g ) at 60 °C, which is much lower than that of the SnO 2 thin film-based hydrogen sensors (100−500 °C). 27,39,40 At the optimum operating temperature, the device with a SnO 2 film thickness of 11.8 nm showed the highest sensor response (R a /R g = 161) and the shortest sensor response time (t res = 83 s) among all samples studied (Figure 4f), which shows its great superiority compared to the SnO ultrathin films obtained before the RTP process (Figure S18).…”

A highly selective, efficient hydrogen gas sensor based on bimetallic (Pd–Au) alloy nanoparticle (NP)-decorated SnO2 nanorods

“…26,27 However, this expansion and contraction of the lattice during hydrogenation and dehydrogenation can make Pd vulnerable to both mechanical and structural instability. 28,29 To address these challenges, blending Pd with other noble metals is being explored as a promising solution. When compared to single-metal counterparts, Pd alloy catalysts exhibit increased stability, tunability, and a synergistic effect, making them valuable in gas sensing applications.…”

Stabilizing Single-Atom Pt on Fe2O3 Nanosheets by Constructing Oxygen Vacancies for Ultrafast H2 Sensing

“…Redox reactions between the target gas and chemisorbed oxygen species are the mechanism of sensing . Fabrication of nanostructured MOS materials with a high specific surface area has proved to be an effective strategy to promote gas adsorption for enhanced sensing performance. , Alternatively, noble metal particles (such as Pt, , Pd, Rh, and Au) are extensively utilized as catalysts to optimize the sensing performance of MOS sensors due to their remarkable electronic and catalytic activity. Noble metal industrial applications in chemical sensors are, however, severely limited by their high cost.…”