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The high porosity of the three-dimensional ordered macroporous structure of inverse opal photonic crystals (IOPCs) provides an ideal platform for gas sensing based on metal oxide semiconductors. Herein, Pt cluster-loaded In2O3 IOPCs were fabricated, and displayed a significantly improved response to ethanol. Various characterization techniques were used to verify the successful preparation of Pt cluster-loaded In2O3 IOPCs. In2O3 IOPCs exhibit closely arranged three-dimensional (3D) ordered macroporous structures, which contain periodic voids with an average diameter of about 150 nm and a uniform wall thickness of 20 nm. Their gas sensing performance is significantly improved at a Pt cluster loading of 2.0 wt%. Gas sensor tests showed that Pt cluster-loaded In2O3 IOPC sensors exhibited an excellent ethanol response (Ra/Rg = 103 to 50 ppm at 240 °C), which was more than 5 times higher than the response of pure In2O3 IOPCs. The sensor also demonstrated an ultra-fast response/recovery time (7/9 s), impressive selectivity, reproducibility, and long-term stability. The significantly enhanced sensing performance of Pt cluster-loaded In2O3 IOPCs is attributed to the synergistic effects of the connected 3D ordered macroporous structure, chemical and electronic sensitization of Pt nanoparticles, and p–n heterojunctions between p-type PtO, p-type PtO2 and n-type In2O3. The present findings are expected to provide enlightening insights into the design and fabrication of gas sensors with an ultra-high response and an ultra-fast response/recovery speed. [ABSTRACT FROM AUTHOR]

CH4 sensors based on metal oxide semiconductors (MOS) provide high sensitivity and fast response, but the sensitivity will be lost when they are poisoned by silicone. Therefore, there is an urgent need to address the poisoning deactivation of MOS gas sensors caused by silicone. Here, the unique strategy of coating a reactive anti-poisoning material onto the surface of the sensing material is proposed to effectively improve the anti-poisoning ability without degrading the gas sensing performance. As an experimental verification, SnO2/α-Al2O3 is designed as the anti-poisoning layer and SnO2 loaded with precious metals (Pt and Pd) as the sensing layer. Owing to the protection of the anti-poisoning layer, the response (Ra/Rg = 24.69) and the response/recovery time (1/24 s) of the sensor to CH4 remained undiminished at 364 °C after being poisoned under an air/hexamethyldisiloxane (HMDSO) (10 ppm) environment for 40 min, which meets the requirements of the Chinese National Standard (GB 15322.2-2019). The mechanism analysis shows that HMDSO can be decomposed with the adsorbed oxygen on the surface of SnO2 in the anti-poisoning layer, and CH4 can diffuse into the sensing layer to be detected. The unique anti-poisoning strategies can provide a promising insight for improving the poisoning tolerance of MOS gas sensors. [ABSTRACT FROM AUTHOR]

Due to its high refractive index, photocatalytic activity, and photoinduced superhydrophilicity, TiO2 has advantages in photonic crystals (PCs). However, the composite of TiO2 and PCs needs to be calcined at high temperatures, and the structural stability of the composites is poor. In this study, photoinduced superhydrophilic TiO2–poly(hydroxyethyl acrylate)/polystyrene (PHEA/PS) PC composites with strong structural colors and self‐cleaning are fabricated by coating triethanolamine‐modified anatase TiO2 nanoparticles‐hydroxyethyl acrylate on the surface of PS PCs. The ordered arrays can be retained after the superficial layers of PS PCs are filled with TiO2–PHEA, and vivid blue, green, and red composites can be obtained. The water contact angles of the composites can be reduced to 3° in 0.4 s, and superhydrophilicity can be maintained for 180 days in a laboratory environment. The declining superhydrophilicity can be restored under UV irradiation. The composites can degrade the adsorbed methylene blue under UV irradiation. Photocatalytic activity and superhydrophilicity impart self‐cleaning ability on the composites. The locking of PS arrays by TiO2–PHEA enhances the structural stability of the composites, making them resistant to water soaking and washing. Therefore, the composites show prospects for decoration, fabric coloring, and wearable electronic devices. [ABSTRACT FROM AUTHOR]

The powder metallurgy high-strength Ti-1Al-8V-5Fe alloy (Ti-185 alloy) was investigated in this paper with different addition methods of alloying elements, Al, V, Fe pure elements powder (EP) or 1Al-8V-5Fe ternary master alloy powder (MAP), based on TiH2powders at the sintering temperature from 1150 to 1350°C. The results indicate that the Ti-185 alloy with the 1Al-8V-5Fe master alloy (Ti-185 MAP alloy) possesses the higher relative sintered density, less oxygen content, and lessα-phase volume fraction versus the Ti-185 alloy with Al, V, and Fe pure elements (Ti-185 EP alloy). No matter where the sintering temperature is 1150, 1250, or 1350°C, Ti-185 MAP alloy invariably has the higher yield strength and hardness which have a strong relationship to its higher density and less volume fraction of softerα-phase in comparison with Ti-185 EP alloy. [ABSTRACT FROM AUTHOR]

The low-cost Ti-1Al-8V-5Fe (Ti-185) alloy with a high strength is prepared by cold-compaction-and-sintering powder metallurgy process with low-cost titanium hydride (TiH2) powders and FeV80master alloy powders. The use of simple technique process and cheap alloying elements can lead to the cost reduction for titanium alloys. The thermal decomposition of TiH2-1Al-8V-5Fe is analyzed by thermal gravimetric analyses and differential scanning calorimetry simultaneous thermal analyzer. The shrinkage behavior of TiH2-1Al-8V-5Fe during the sintering process is employed by the high-sensitivity dilatometer system. The microstructure of sintered Ti-185 consists of β-phase and lamellar α-phase. The results show that the sintered Ti-185 alloys have the relative density of 97.8%, homogeneous composition, and fine grains. The yield strength and the hardness are 1461 MPa and 40.1 ± 1.0 HRC (unit of Rockwell hardness), which are better than that of as-cast Ti-185. [ABSTRACT FROM AUTHOR]

The surface oxidization characteristics of sponge Ti, hydrogenized TiH 2 and dehydrogenized HDH-Ti are investigated by XPS depth analysis. The results show that the oxygen content increases after the hydrogenation and decreases after the dehydrogenation. Meanwhile, the H 2 O (g) is released in the dehydrogenation process of TiH 2 . The H atoms react preferentially with Ti 3 O 5 followed by Ti 2 O 3 , TiO 2 , TiO in the dehydrogenation process of TiH 2 . [ABSTRACT FROM AUTHOR]