One-Step Hydrothermal/Solvothermal Preparation of Pt/TiO2: An Efficient Catalyst for Biobutanol Oxidation at Room Temperature

The selective oxidation of biobutanol to prepare butyric acid is an important conversion process, but the preparation of low-temperature and efficient catalysts for butanol oxidation is currently a bottleneck problem. In this work, we prepared Pt-TiO2 catalysts with different Pt particle sizes using a simple one-step hydrothermal/solvothermal method. Transmission electron microscopy and X-ray diffraction results showed that the average size of the Pt particles ranged from 1.1 nm to 8.7 nm. Among them, Pt-TiO2 with an average particle size of 3.6 nm exhibited the best catalytic performance for biobutanol. It was capable of almost completely converting butanol, even at room temperature (30 °C), with a 98.9% biobutanol conversion, 98.4% butyric acid selectivity, and a turnover frequency (TOF) of 36 h-1. Increasing the reaction temperature to 80 and 90 °C, the corresponding TOFs increased rapidly to 355 and 619 h-1. The relationship between the electronic structure of Pt and its oxidative performance suggests that the synergistic effect of the dual sites, Pt0 and Pt2+, could be the primary factor contributing to its elevated reactivity.

[Numerical simulation study on dust transport law in antibiotic raw material drug powder screening workshop]

To study the distribution pattern of drug dust in the antibiotic raw material drug powder screening workshop and improve the working environment, we used COMSOL Multiphysics 6.0 software to simulate and study the airflow distribution and dust transport law in the powder screening workshop. The results indicated that the dust in the powder screening workshop diffused rapidly with the airflow and reached a stable state at the 100th second. After the dust migrated to a stable state, the area with excessive dust concentration (dust concentration>6 mg/m(3)) widely distributed, mainly distributed in the middle and lower parts of the wall opposite the air inlet from the rotary vibrating screen. The distribution of dust showed a characteristic of local aggregation, and dust transport was related to airflow movement, which was prone to aggregation in areas with low airflow velocity and eddy currents. On the plane of the human respiratory belt height (h=1.5 m), the concentration near the dust producing surface was high, with local concentrations exceeding 32 mg/m(3). It was the key area for dust prevention and control. And the working environment can be improved by changing the air flow distribution in the workshop or other dust reduction methods.