New insight into ZnO@ZIFs composite: an efficient photocatalyst with boosted light response ability and stability for CO2 reduction.

One of the main causes of climate change and energy exhaustion is the excessive use of fossil fuels. Photocatalytic carbon dioxide (CO2) reduction technology uses inexhaustible sunlight to directly convert CO2 into value-added chemicals or fuels not only solving the problem of greenhouse effect but also alleviating the shortage of fossil energy. In this work, a well-integrated photocatalyst is synthesized through growing zeolitic imidazolate frameworks (ZIFs) with different metal nodes on ZnO nanofiber (NFs) for CO2 reduction. One-dimensional (1D) ZnO NFs have better CO2 conversion efficiency due to the high surface-to-volume ratio and low light reflectivity. 1D nanomaterials with superior aspect ratios can be assembled into free-standing flexible membranes. In addition, it has been found that ZIFs nanomaterials with bimetallic nodes not only have better CO2 reduction capabilities but also exhibit superior thermal and water stability. The photocatalytic CO2 conversion efficiency and selectivity of ZnO@ZCZIF are shown to be significantly enhanced which can be attribute to the strong CO2 adsorption/activation, efficient light capture, excellent electron-hole pair separation efficiency, and specific metal Lewis sites. This work provides insights into the rational construction of well-integrated composite materials to improve the photocatalytic carbon dioxide reduction performance.

Bismuth oxide modified V2C MXene as a Schottky catalyst with enhanced photocatalytic oxidation for photo-denitration activities.

In this work, a new composite photocatalyst was synthesized by flower-like Bi2O3 and two-dimensional multilayer V2C using a facile hydrothermal method. Compared with the pristine sample, the specific surface area of Bi2O3/V2C MXene composite is significantly increased, which is favourable to improve the photocatalytic efficiency. The analysis of the UV-vis absorption spectrum and band gap energy shows that the construction of heterojunction broadens the light response range, improves the light absorption capacity, and obtains a narrower band gap than any of the single component, which is beneficial to the utilization of light. PL, TPC and EIS analysis revealed that Bi2O3/V2C MXene composite had stronger carrier mobility, which further confirmed that the photocatalytic oxidation performance of the system was the dominant reason in the photocatalytic NO pollutant removal process. This study provides a new idea for better understanding the two-dimensional MXene material-based photocatalyst and improving the NO removal efficiency.

Calibration method for structure parameters of a binocular stereo vision system equipped with polarizers.

For structure parameter calibration of a binocular stereo vision system equipped with polarizers, the optimal calibration polarization angle needs to be determined. There are no corresponding solutions for the determination of the optimal polarization angle of structure parameter calibration. Furthermore, existing research considers the polarization angle that causes the image to possess the lowest brightness (gray value) as the optimal polarization angle. This reduces image contrast, and eventually the texture information of the image is lost, which also affects the accuracy of feature extraction. In this paper, we propose a new calibration method for the structure parameters of a binocular stereo vision system equipped with polarizers. We calculated the pose of the target relative to each camera for different polarization angles. The sum of the object-space errors corresponding to each polarization angle was considered as the evaluation criterion to determine the optimal calibration polarization angle. The calibration of structure parameters was finished using images captured on the premise of the optimal calibration polarization angle. This angle can also be considered as the reference of the polarization angle for measurement. Experiment results show that using the calibration results of our method, the reconstructed length error of a 275×200mm target was less than ±0.052mm, the reconstructed linear displacement error was less than ±0.048mm for the range of 0-30 mm, and the reconstructed rotary angle error was less than ±0.048∘ for the range of-30∘-30∘.