In this study, Eu 2+ /Eu 3+ coexisting perovskite LaAlO 3 phosphors were synthesized by a traditional high-temperature solid-phase reaction method and investigated via X-ray diffraction data, X-ray photoelectron spectroscopy and temperature-dependent photoluminescence spectra. The Eu 2+ /Eu 3+ coexisting LaAlO 3 phosphors exhibit excellent optical temperature sensing characteristics and are potential inorganic materials for temperature detection. The measured maximal absolute temperature sensitivity reaches 0.014 K -1 , and the corresponding largest relative temperature sensitivity is 1.193% K −1 , which are superior to most of previous reports of that. Meanwhile, the monitored signal peaks are well separated, providing a good signal discriminability. The energy level crossover relaxation of Eu 2+ and Struck-Fonger crossover process involving O 2– -Eu 3+ charge transfer band were used to explain the different temperature-dependent responses of Eu 2+ and Eu 3+ . This work may give new ideas for the future research of optical thermometric materials with high sensitivity and high discriminability.
Graphitic carbon nitride (g-C 3 N 4 ) has been widely studied and applied in the field of catalysis, but its photocatalytic performance still needs to be improved. In this work, g-C 3 N 4 was protonated with hydrochloric acid and nitric acid, and the products were denoted as HCN and NCN, respectively. The photocatalytic performances of g-C 3 N 4 , HCN, and NCN were compared by the degradation of Rhodamine B solution (RhB) under visible light. The structure, morphology, optical, and electrochemical properties of the samples were systematically characterized. It was found that both HCN and NCN were composed of uniform nanosheets, and HCN had a better separation. The UV–Vis and PL spectra showed that the band gap of the material was widened, and the photogenerated electron-hole pairs can be effectively separated. From the photocatalytic degradation test, HCN and NCN showed stronger photocatalytic activity than g-C 3 N 4 , and the degradation efficiency was HCN > NCN > g-C 3 N 4 , the degradation of RhB were 98%, 95%, and 78% respectively at 75 min. The experiment of the free radical scrubber showed that superoxide free radical was the main active substance of photocatalytic degradation. Our results have potential application value for the design of two-dimensional photocatalytic materials.
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