Ultralow detection limit and ultrafast response/recovery of the H2 gas sensor based on Pd-doped rGO/ZnO-SnO2 from hydrothermal synthesis

Abstract

Hydrogen (H2) sensors are of great significance in hydrogen energy development and hydrogen safety monitoring. However, achieving fast and effective detection of low concentrations of hydrogen is a key problem to be solved in hydrogen sensing. In this work, we combined the excellent gas sensing properties of tin(IV) oxide (SnO2) and zinc oxide (ZnO) with the outstanding electrical properties of reduced graphene oxide (rGO) and prepared palladium (Pd)-doped rGO/ZnO-SnO2 nanocomposites by a hydrothermal method. The crystal structure, structural morphology, and elemental composition of the material were characterized by FE-SEM, TEM, XRD, XPS, Raman spectroscopy, and N2 adsorption–desorption. The results showed that the Pd-doped ZnO-SnO2 composites were successfully synthesized and uniformly coated on the surface of the rGO. The hydrogen gas sensing performance of the sensor prepared in this work was investigated, and the results showed that, compared with the pure Pd-doped ZnO-SnO2 sensor, the Pd-doped rGO/ZnO-SnO2 sensor modified with 3 wt% rGO had better hydrogen (H2)-sensing response of 9.4–100 ppm H2 at 380 °C. In addition, this sensor had extremely low time parameters (the response time and recovery time for 100 ppm H2 at 380 °C were 4 s and 8 s, respectively) and an extremely low detection limit (50 ppb). Moreover, the sensor exhibited outstanding repeatability and restoration. According to the analysis of the sensing mechanism of this nanocomposite, the enhanced sensing performance of the Pd-doped rGO/ZnO-SnO2 sensor is mainly due to the heterostructure of rGO, ZnO, and SnO2, the excellent electrical and physical properties of rGO and the synergy between rGO and Pd.

Characterization and Modeling of a Pt-In2O3 Resistive Sensor for Hydrogen Detection at Room Temperature

“…First, the standard deviation in the baseline of the response curve (rms noise ) was calculated from 20 data points, which is 0.003828, representing the level of the sensor noise. The slop of the linear fitting of gas response versus gas concentration at RT is 75.81454 according to Figure 2 c. Therefore, the DL = 3rms noise /slop = 1.51 ppm according to literature [ 24 , 25 ]. Additionally, a comparison between the proposed sensor of this work and recent H 2 sensors based on various sensitive materials was conducted as shown in Table 1 [ 6 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 ].…”

Self-Powered Thermoelectric Hydrogen Sensors Based on Low-Cost Bismuth Sulfide Thin Films: Quick Response at Room Temperature

“…Table shows the critical sensing characteristics of recently reported representative TE hydrogen sensors, such as response and recovery time. It is evident that the TEH sensors reported in this work respond and recover faster than most reported TE hydrogen sensors. ,,,,,,,− In addition, to compare material characteristics, we collected the LD50 values (median lethal dose) and prices of various elements contained in the most used materials of the TEH sensors, which were normalized to the price of 99.99% Te (Figure S7).…”

First-Principles Investigation of Adsorption Behaviors and Electronic, Optical, and Gas-Sensing Properties of Pure and Pd-Decorated GeS2 Monolayers

“…The described charge redistribution and transfer due to gas adsorption is expected to play a major role in the current–voltage characteristics. Due to the charge transfer between the molecule and GeS 2 , we can obtain the resistivity change of the material experimentally and therefore can exploit it in gas sensors. − Since formaldehyde (HCHO) is also a kind of hazardous indoor gas dangerous to human health, we also considered the possibility of the GeS 2 monolayer as an HCHO sensor. The most stable configuration of HCHO on the monolayer is shown in Figure S1 in the Supporting Information.…”