Papers by Author: Xiu Cheng Zheng

Abstract: Dodecatungstophosphoric acid was synthesized and used as catalyst for oxidation of benzaldehyde to benzoic acid with aqueous hydrogen peroxide. The effect of various catalytic reaction parameters including time, temperatures, and the amount of catalyst on the yield of benzoic acid was investigated in details. The results indicated that the as-prepared sample was in the keggin-type structure and the optimal parameters under the reaction conditions were as follows: 0.5 g of catalyst, reacted at 80 C for 5 h.

Abstract: NiO nanoarrays with different hierarchical porous structures were synthesized by using hard-template SBA-15. The analytic results showed that the mesoporous structure parameters of the as-prepared NiO nanoarrays increased obviously with the increase of the addition of SBA-15 to a certain extent. The results may be helpful for the utilization of NiO as supercapacitors.

Abstract: Lead-free (1-x)Bi_0.5Na_0.5TiO₃-xBaTiO₃ (BNT-xBT) nano-powders synthesized by a modified citrate method and the sintered ceramics were characterized using various techniques. The r_{Subscript text}esults indicated that all the BNT-xBT samples were homogeneous with a pure perovskite crystal structure. It is found BNT-0.1BT exhibit_{Subscript text}s the best ferroelectric properties. BNT-0.0_{Subscript text}6BT has excellent performance in thermo-electrical energy conversion.

Abstract: W-SBA-15 mesoporous material was synthesized by using a one-step co-condensation sol-gel process and characterized by various methods. The results showed that the prepared W-SBA-15 sample retained the typical mesoporous structure of SBA-15 and exhibited good catalytic performance for the green synthesis of adipic acid under organic solvent-free conditions.

Abstract: Ferroelectric0.90Bi_0.5Na_0.5TiO₃-0.10BaTiO₃ (0.90BNT-0.10BT) thin film with single perovskite phase is prepared using an improved sol-gel spin coating method onto indium-tin-oxide (ITO) glass substrates. A new solution process is developed for the preparation of precursor solution which is stable in air, presenting a low gelation and trend to the formation of precipitates. The as-prepared thin film is crystallized into single perovskite phase and has good ferroelectric properties. It is remarkable that the thin films show excellent heat-to-electrical energy conversion properties. The results of this work for the first time demonstrate the feasibility of using lead-free BNT-BT films for pyroelectric energy harvesting.

Abstract: Bismuth sodium titanate (Bi_0.5Na_0.5TiO₃ , abbreviated as BNT) nanoparticles were synthesized by hydrothermal process at various temperatures for 10 h. The results showed that all the as-prepared nanopowders are well crystallized and the crystallite size increased with the increase of hydrothermal temperatures under the reaction conditions.

Abstract: Ti-SBA-15 mesoporous materials with different Si/Ti molar ratios were synthesized via a hydrothermal process and characterized by using various techniques. The effect of Si/Ti molar ratios in the gels on the structure and catalytic efficiency in epoxidation of cyclohexene was discussed in details. The results showed that all the Ti-SBA-15 materials retained SBA-15 mesoporous structure and exhibited good catalytic activity. Furthermore,the sample prepared with Si/Ti =50 exhibited the best catalytic performance under the reaction conditions.

Abstract: BaTiO3 nanoparticles were synthesized by hydrothermal process at various temperatures for 8 h, starting from a mixture of Ti(OBu)4 + BaCl2. The structure analytic results showed that all the prepared powders are well crystallized. Meanwhile, the phase change ratio from metastable cubic to tetragonal phases increased with the increase of hydrothermal temperatures.

Abstract: Ti-SBA-15 mesoporous materials were directly synthesized via a hydrothermal process and characterized by using nitrogen adsorption-desorption measurements, X-ray diffraction, scanning electron microscopy, transmission electron microscopy, diffuse reflectance ultraviolet-visible spectroscopy, and infrared ray spectroscopy. The effect of synthesis temperatures on the structure and catalytic efficiency in epoxidation of cyclohexene was discussed in details. The results showed that the optimal temperature was 100 °C under the reaction conditions.