Urchin-Like WO_2.72 Microspheres Decorated with Au and PdO Nanoparticles for the Selective Detection of Trimethylamine

Abstract

Urchin-like WO2.72 microspheres modified with Au and PdO nanoparticles were constructed and applied to the field of gas sensors. The gas-sensing test results showed that the Au/PdO/WO2.72 sensors exhibited excellent gas-sensitive performances. The sensors have not only an ultrahigh response to TMA but also a rapid response/recovery time. Especially WO2.72 decorated with 2 wt % Au and 2 wt % PdO nanoparticles (2%AuPW), its response to 40 ppm of TMA can be up to 802.5 at 240 °C, which is approximately 110.5 and 1.6 times of WO2.72 (7.26) and 2 wt % PdO/WO2.72 (496.6) at 260 °C, respectively. Even for 1 ppm of TMA, the response of the as-obtained 2%AuPW sensor can still attain 10.9. Furthermore, the Au/PdO/WO2.72 sensor showed excellent effectiveness after 30 days. The BET results indicate that the deposition of PdO and Au nanoparticles increases the specific surface area of the sample. The mechanism analysis revealed that the markedly increased gas-sensing properties of Au/PdO/WO2.72 sensors are ascribed to the synergy of surface area and a mesoporous structure, a p–n heterojunction, and a catalytic spillover effect of PdO and Au nanoparticles. The rational design and detailed investigation of Au/PdO/WO2.72 sensors provide insights into the development and design of other semiconductor-based sensors.

Bimetallic Au@Pt Nanocrystal Sensitization Mesoporous α-Fe2O3 Hollow Nanocubes for Highly Sensitive and Rapid Detection of Fish Freshness at Low Temperature

“…In addition, the signal of Pt 2+ 4f 5/2 (73.1 eV) and Pt 2+ 4f 7/2 (75.7 eV) revealed the existence of PtO oxides, which were caused by the partial oxidation of the Pt components during calcination Figure d presented signals for Au 4f 5/2 (87.2 eV) and Au 4f 7/2 (83.5 eV), which implied that the Au element existed in the Au0 state. , Compared to the previously reported values of gold metal positions, there also existed a slight shift as the electrons in α-Fe 2 O 3 were transferred to Au, which subsequently formed a Schottky junction. , As we all know, the formation of the abovementioned PtO oxides and Schottky junction is beneficial for detection performance. , As shown by the results of XPS, the elements, including Fe, O, Au, and Pt, were observed in the survey spectrum (Figure S2), which was also in accordance with the EDS and TEM characterizations (Figure ). These results further proved that the bimetallic Au@Pt nanocrystals were deposited on α-Fe 2 O 3 NCs successfully.…”

“…44,51 Compared to the previously reported values of gold metal positions, there also existed a slight shift as the electrons in α-Fe 2 O 3 were transferred to Au, which subsequently formed a Schottky junction. 3,52 As we all know, the formation of the abovementioned PtO oxides and Schottky junction is beneficial for detection performance. 53,54 As shown by the results of XPS, the elements, including Fe, O, Au, and Pt, were observed in the survey spectrum (Figure S2), which was also in accordance with the EDS and TEM characterizations (Figure 2).…”

“…Trimethylamine (TMA), as an organic amine, is one of the direct factors of seafood corrosion. − Its concentration is becoming significantly increased with seafood’s spoilage period extending and freshness decreasing. The demand for aquatic products (e.g., fishes) is growing all around the world because they contain trace amino acids and unsaturated fatty acid, which are beneficial to human’s immune system, maintaining vital metabolism and preventing neurological diseases. , Eating spoiled food, however, could arise many diseases such as fever and diarrhea .…”

“…Over the past few decades, a metal oxide semiconductor (MOS)-based gas sensor has attracted intensive attentions due to its portability, long-term stability, and easy fabrication, which can detect trace amounts of volatile organic compounds, including TMA . The mostly used MOSs include SnO 2 , , WO 3 , , MoO 3 , and α-Fe 2 O 3 . Among these MOSs, hematite (α-Fe 2 O 3 ), as a common n-type semiconductor, is stable in itself.…”

Tough and Antifreezing MXene@Au Hydrogel for Low-Temperature Trimethylamine Gas Sensing

“…Researchers have sufficiently demonstrated gas-sensing materials modified by noble metals (Au, Ag, Cu, Pd, and Pt) can significantly enhance the sensing properties in terms of gas sensitivity, selectivity, and stability. , Noble metal nanoparticles on sensing materials are reported to enable catalytic sensitization in boosting surface reaction, including the dissociation of target gas molecules and other relevant processes . Meanwhile, it can further improve the gas sensitivity by increasing the specific surface area of the material . Unfortunately, several drawbacks of the MXene have been revealed, such as poor stability and mechanical properties, which limit the further development and application of the MXene.…”