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Mechanical energy can be directly transformed into chemical energy by piezoelectric materials, namely, piezocatalysis, which is a potential tactic for renewable clean energy collection and environmental purification. The piezocatalytic efficiency strongly relies on the piezoelectric property and free charge concentration of piezocatalysts. Here, four samarium-doped (1 – x)­Pb­(Mg1/3Nb2/3)­O3-xPbTiO3 nanostructures were designed to investigate the correlation between the piezoelectric property and piezocatalytic performance. The diverse dye degradation efficiencies confirmed the high piezoelectric coefficient toward high catalytic activity. The degradation efficiency for acid orange 7 (AO7) was 100% within 20 min, while those for methyl orange (MO), methylene blue, and rhodamine B dyes were 97, 78, and 72%, respectively, within 40 min under ultrasonic vibration only. Furthermore, high catalytic efficiency of 96% was still maintained for AO7 degradation after 10 consecutive degradation cycles for samarium-doped 0.70Pb­(Mg1/3Nb2/3)­O3-0.30PbTiO3 due to its high piezoelectric coefficient. The investigation of the catalytic mechanism demonstrated that hole and superoxide radicals were the primary active species toward AO7 degradation, whereas hydroxyl and hole radicals were for MO degradation. This work not only demonstrates the highly efficient catalytic activity of samarium-doped (1 – x)­Pb­(Mg1/3Nb2/3)­O3-xPbTiO3 nanostructures but also gives a deep comprehension of the correlation between the piezoelectric property and catalytic performance of piezocatalysts.

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Taking the Guangxi Beibu Gulf Economic Zone as the study area, this paper utilizes the geographical detector model to quantify the feedback effects from the terrestrial environment on precipitation variation from 1985 to 2010 with a comprehensive consideration of natural factors (forest coverage rate, vegetation type, terrain, terrestrial ecosystem types, land use and land cover change) and social factors (population density, farmland rate, GDP and urbanization rate). First, we found that the precipitation trend rate in the Beibu Gulf Economic Zone is between −47 and 96 mm/10a. Second, forest coverage rate change (FCRC), urbanization rate change (URC), GDP change (GDPC) and population density change (PDC) have a larger contribution to precipitation change through land-surface feedback, which makes them the leading factors. Third, the human element is found to primarily account for the precipitation changes in this region, as humans are the active media linking and enhancing these impact factors. Finally, it can be concluded that the interaction of impact factor pairs has a significant effect compared to the corresponding single factor on precipitation changes. The geographical detector model offers an analytical framework to reveal the terrestrial factors affecting the precipitation change, which gives direction for future work on regional climate modeling and analyses.