Xiao Cheng,Rong Chen,Xun Zhu,Qiang Liao,Xuefeng He,Shuzhe Li,Lin Li
Photocatalytic reduction of CO 2 is a promising technology to capture CO 2 and convert it into solar fuels simultaneously. However, current photoreactors usually face the problems of low specific surface area, non-uniform light distribution and poor photon transfer. To address these issues, a novel optofluidic membrane microreactor with high surface-area-to-volume ratio, enhanced photon and mass transport and uniform light distribution was proposed in this work by combining optofluidics with the membrane reactor technology for the photocatalytic reduction of CO 2 with liquid water. A TiO 2 /carbon paper composite membrane was prepared as the photocatalytic membrane via coating TiO 2 onto the carbon paper followed by hydrophobic treatment by poly-tetrafluoroethylene (PTFE) for the separation of the gas/liquid phases. The performance of the proposed optofluidic membrane microreactor was evaluated by measuring the methanol yield. The effects of the liquid water flow rate , light intensity and catalyst loading on the methanol yield were also studied. It was shown that a maximum methanol yield of 111.0 μmole/g-cat·h was achieved at a flow rate of 25 μL/min and under the light intensity of 8 mW/cm 2 , which is among the top in comparison to the reported data. Results obtained fully demonstrate the feasibility and superiority of the proposed optofluidic membrane microreactor for the photocatalytic reduction of CO 2 .
Use of 3D photocatalytic reactor has been widely explored for development of efficient photocatalytic systems. In the present study, a bionic palisade cells BiOBr/Sr 2 Nb 2 O 7 /Al 6 Si 2 O 13 photocatalytic reactor with high strength was prepared through combination of 3D printing technology and solvothermal method. The carefully designed and optimized bionic palisade cell structure exhibited a periodic porous structure with high surface area. The controllable periodic structure effectively regulated the internal photon transfer and mass transfer. Photon transfer ensured that light is fully scattered within the structure, which improved light utilization. High mass transfer ensured smooth flow of reactant inside the structure, which increased reactant adsorption on the surface of photocatalysts. The interface electric field of the BiOBr/Sr 2 Nb 2 O 7 p-n heterojunction effectively separated the photogenerated electrons and holes. The BOB/SNO/ASO structure had high photocatalytic CO 2 reduction performance under the simulated sunlight. The CO yield for the reaction was 13.68 μmol/g/h, whereas that of CH 4 yield was 6.37 μmol/g/h. Therefore, the findings of the present study provide a basis for design and preparation of high-performance 3D photocatalytic reactors.
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