Kaijie Wei,Xiaoya Feng,Hao Jiang,Chunzhong Li,Yanjie Hu
In recent years, the development of heat-resistant silicone rubber has been a research hotspot. In this paper, a kind of Fe doped TiO 2 nanoparticles (Fe-TiO 2 ) was prepared via flame spray pyrolysis, which can significantly improve the high temperature resistance of silicone rubber. The results show that, on the one hand, the prepared Fe-TiO 2 can inhibit the breakage of Si-O main chain; on the other hand, because Fe is doped into the lattice of TiO 2 , it causes the change of TiO 2 crystal phase and produces more oxygen vacancies, which is more beneficial to capture free radicals in silicone rubber matrix, so that Fe-TiO 2 can effectively inhibit the excessive cross-linking of silicone chain caused by methyl oxidation on the side of silicone rubber. TGA results showed that after adding Fe-TiO 2 , the 5 % thermal weight loss temperature of methyl vinyl silicone rubber increased from 392.8 °C to 435.6 °C.
Yu Shao,Zhisheng Mao,Jiarui Wang,Xianfeng Hao,Yongchao Jia,Yuanhui Xu,Keju Sun
The electrochemical synthesis of hydrogen peroxide through two-electron oxygen reduction (2e– ORR) presents a sustainable alternative to conventional synthesis methods, such as the anthraquinone method. TiO2-based materials are promising candidates due to their stability and tunable electronic properties, but their intrinsic 2e– ORR activity and selectivity are insufficient for practical applications. Here, we report that strategic Fe doping significantly enhances the 2e– ORR performance of TiO2. The optimized Fe-TiO2 catalyst exhibits remarkable activity and selectivity, achieving a 30% increase in H2O2 selectivity (from 47% to 77%) while reducing the electron transfer number from 3.05 to 2.45 in 0.1 M KOH electrolyte. Notably, the material shows substantially improved electrochemical active surface area (ECSA) and ORR kinetics, culminating in an exceptional H2O2 production rate of 406 mmol·gcat–1·h–1 with 97.5% Faraday efficiency at 0 V vs RHE in an H-cell configuration. Density functional theory (DFT) calculations reveal the mechanistic origins of this enhancement: Fe doping effectively narrows the band gap and lowers the oxygen vacancy formation energy, thereby boosting electrical conductivity as confirmed by experimental characterization; and the modified electronic structure increases Bader charge accumulation on the terminal oxygen of adsorbed *OOH intermediates, facilitating protonation at this site and consequently promoting the 2e– pathway. These dual effects synergistically enhance both ORR activity and H2O2 selectivity. This study not only presents Fe-TiO2 as an efficient, earth-abundant catalyst for sustainable H2O2 production but also establishes fundamental design principles for developing advanced metal oxide electrocatalysts through targeted heteroatom doping.
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