Cu-doped SnO2/rGO nanocomposites for ultrasensitive H2S detection at low temperature

Abstract

Hydrogen sulfide (H2S) detection remains a significant concern and the sensitivity, selectivity, and detection limit must be balanced at low temperatures. Herein, we utilized a facile solvothermal method to prepare Cu-doped SnO2/rGO nanocomposites that have emerged as promising candidate materials for H2S sensors. Characterization of the Cu-SnO2/rGO was carried out to determine its surface morphology, chemical composition, and crystal defects. The optimal sensor response for 10 ppm H2S was ~1415.7 at 120 °C, which was over 320 times higher than that seen for pristine SnO2 CQDs (Ra/Rg = 4.4) at 280 °C. Moreover, the sensor material exhibited excellent selectivity, a superior linear working range (R2 = 0.991, 1–150 ppm), a fast response time (31 s to 2 ppm), and ppb-level H2S detection (Ra/Rg = 1.26 to 50 ppb) at 120 °C. In addition, the sensor maintained a high performance even at extremely high humidity (90%) and showed outstanding long-term stability. These superb H2S sensing properties were attributed to catalytic sensitization by the Cu dopant and a synergistic effect of the Cu-SnO2 and rGO, which offered abundant active sites for O2 and H2S absorption and accelerated the transfer of electrons/holes.

Achieving Room-Temperature ppb-Level H2S Detection in a Au-SnO2 Sensor with Low Voltage Enhancement Effect

“…(a) Selectivity under different gas concentration and (b) 12 times repeatability curve of Au/SnO 2 based sensor at 50 ppb H 2 S gas concentration at operating voltage of 0.5 V. (c) Comparison of the overall performance of the proposed Au/SnO 2 -based H 2 S sensor with the best low LOD H 2 S sensors (SnO 2 -based), − and (d) low-operating voltage H 2 S sensors reported at various working temperatures (metal-oxide-based). ,,, …”

“…For instance, mesoporous SnO 2 36 and ZnO-SnO 2 nanofiber-based 37 H 2 S sensors exhibit low LODs of 0.5 ppb (at 92 °C) and 10 ppb (at 350 °C), respectively. Additionally, SnO 2 /rGO/PANI nanocomposite (at RT)-, 35 Co and N-doped GQDs/SnO 2 (at 260 °C) mesoporous microsphere-, 39 and Cu-doped SnO 2 /rGO nanocomposite (at 120 °C) 40 -based sensors also show very low LODs of 50 ppb toward H 2 S gas. It is worth noting that the most efficient sensors operate at high operating temperatures.…”

“…Therefore, research efforts are aimed at achieving the best performance of SnO 2 -based H 2 S gas sensors through preferable modifications and structures. Table S2 − presents a comparison of recent SnO 2 composite-based H 2 S gas sensors with different key parameters, such as working temperature, gas concentration, gas response, response/recovery time, and LOD. It is observed that sensors based on different types of nanostructures, such as nanotubes, nanoporous materials, , nanofibers, , and nanoflakes, demonstrate superior gas sensing performance due to their large surface area.…”

Influence of ‘period four’ transition metal doping in graphene on adsorption and transduction characteristics for CO gas- A detailed ab-initio perspective

“…The structural stability of various doped lattices is computed in terms of cohesive energy, which is least affected by Mn doping, and the lattice becomes most structurally unstable by Zn doping. In this study, all the dopant atoms typically have a similar atomic radius [36], resulting in a similar variation in the bond length and lattice vectors of all the doped lattices.…”

“…However, to date, the majority of the reports on metal-doped Gr for gas sensing applications are theoretical in nature, and only a few reports experimentally attempted to realize metal-modified Gr for gas sensor design. In this line, superior NO 2 sensing using Ag-modified reduced graphene oxide (rGO) [32] and Au-modified rGO [33], H 2 S and SOF 2 sensing using Ag-modified Gr [34], NH 3 sensing using Zn-doped rGO/MoS 2 composite [35], H 2 S sensing using Cu-doped rGO/SnO 2 composite [36], CH 2 O sensing using Fe-doped rGO/ZnO composite [37] have been realized. These reports indicate the potential of suitable metal doping/modification techniques for improving both the selectivity and sensitivity of Gr-based gas sensors and, at the same time, suggest the necessity of the DFT-based ab initio investigations for screening, designing and optimizing the modified Gr for high-performance gas sensor realization.…”