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In this study, Bi2Ti2O7−TiO2 was synthesized in a single step via the sol–gel method, after which its photocatalytic properties and mechanisms were investigated. Moreover, our study proposed and evaluated the use of salicylic acid (SA) and basic magenta (BM) as model contaminants in quenching experiments. When SA was used as the model pollutant, the reaction rates showed negative values. Therefore, the experimental results failed to truly and effectively reflect the actual photocatalytic performance of Bi2Ti2O7−TiO2. However, when BM was used as the model pollutant, the reaction rates were all positive and the experimental results were far more descriptive. Hydroxyl radicals (·OH), superoxide radicals (·O2−), and photogenerated holes (h+) all contribute to the photocatalytic activity of Bi2Ti2O7-TiO2, with ·OH making the largest contribution. Collectively, our findings can serve as a basis to improve the accuracy and efficiency of future photocatalytic mechanism experiments, which could bring great economic benefits. [ABSTRACT FROM AUTHOR]

This paper presents a miniaturized ultra-wideband (UWB) antipodal Vivaldi antenna (AVA) array with low-scattering characteristics integrated a hybrid diffusive-absorptive metasurface. Periodic elliptical slots at the outer edges and a dielectric lens are utilized for antenna element to improve performances including miniaturized size, wide bandwidth, and high gain. The optimized element is fabricated and measured, the results demonstrate that the − 10 dB impedance bandwidth is 4.5–50 GHz with a ratio bandwidth (fH/fL) of 11.1:1, and the maximum gain at 35 GHz is 12.7 dBi, which are in good agreement with simulation. By loading an optimized Minkowski-shaped metasurface as the ground reflector, which combines the multielement phase cancellation (MEPC) and EM absorption technology, the 4 × 4 array realizes a low radar cross section (RCS) without the radiation performance degradation. Simulated and measured results show that the proposed low-scattering array has a 10-dB RCS reduction band ranging from 5 to 50 GHz at normal incidence for both polarizations. Furthermore, the array structure shows extremely low-observable capability, which is larger than 15 dB of the RCS reduction from 7.1 to 50 GHz with a ratio bandwidth of 7.0:1. The results verify the feasibility of improving the performance of antenna and the UWB low-scattering functionality. [ABSTRACT FROM AUTHOR]