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Here, using a facile hydrothermal method, the single-crystalline ZnO nanoflowers were firstly synthesized and then annealed at different temperatures from 500 to 900 °C. The results revealed that the as-synthesized samples were flower-like ZnO structures composed of many hollow nanorods; after annealing at 500 °C, hollow nanorods were changed into solid parts. Also, using the as-synthesized and annealed ZnO nanoflowers as photosensitive layers, respectively, a series of ultraviolet photodetectors were built. The results demonstrated that the ultraviolet photodetector based on the ZnO nanoflowers annealed at 800 °C had the best performance when they were exposed to 365 nm light with light intensity of 71 μW/cm2 and its sensitivity, responsivity, gain, response, and decay time were 19,991.3 at − 0.1 V, 9.7 A/W at 5 V, 33.2 at 5 V, 17.1 s, and 49.5 s, respectively. Therefore, a new avenue can be opened to construct low cost and high-sensitivity ultraviolet photodetectors by the annealed ZnO nanoflowers.

The views on catalytic activity of zeolite in isomerization of α-pinene have not came to an agreement. Thus, the key active substance in zeolite was further studied through experiments. H-mordenite was treated in three ways: (i) calcination under nitrogen flows, (ii) calcination under oxygen flows, (iii) calcination under nitrogen flows after alkali treatment. The properties of modified zeolites were investigated by methods of SEM, EDS, XRD, nitrogen adsorption, NH3-TPD, Py-IR, and 29Si and 27Al MAS NMR. The results showed that the zeolites produced mesoporous after 0.4M NaOH solution soaking and calcinations above 500 °C, but it had a slight effect on the change of micropore volumes. Comparison of zeolite acid sites amount under different roasting temperature by NH3-TPD showed that the decrease of acid sites amount was mainly related to the roasting temperature. Py-IR and 27Al MAS NMR experiment revealed that Lewis acid was produced by framework aluminum. Finally, Analysis on the influencing factors we studied of H-mordenite catalytic activity in this paper suggested that, in isomerization of α-pinene, the relative concentration of six-coordination aluminum in zeolite is the dominant factor of provided catalytic activity of H-mordenite.