Mechanism PVA-co-PE Composite Nanofibers Photocatalytic Reduction Of CO₂ Research

Energy crisis and environmental pollution are two major global problems that seriously hinder the sustainable development of human society.The photocatalytic reduction of carbon dioxide（CO₂）technology has received widespread attention because it can reduce the CO₂produced by the combustion of fossil fuels and at the same time produce valuable chemical fuels.Due to its excellent photoelectric properties,iron-based metal-organic frameworks have become a promising photocatalyst in many applications where solar-induced CO₂reduction is driven.Although iron-based metal organic framework materials have made some progress in the photocatalytic reduction of CO₂in recent years,the stability and catalytic activity of photocatalytic systems based on these materials are still a big challenge.Therefore,it is of great significance to prepare a flexible and transparent composite film that can respond to CO₂stimulation in the environment so as to spontaneously and reversibly adjust its own light transmittance.In this paper,PVA-co-PE nanofiber membranes are used as fillers and cross-linked and polymerized with photocatalysts to prepare MOFs/PVA-co-PE nanofiber transparent composite membranes with high transparency,softness and reversibly adjustable transparency.This article has carried out the following three aspects of work around this issue:（1）The MOFs/SiC composites with good stability were prepared by in-situ synthesis at room temperature.The SiC doped in different proportions are compounded with Fe-MOFs.When the power of the xenon lamp is 300W and the pressure of the CO₂reduction reaction is60～80k Pa,the performance results show that the photocatalytic activity of the 10%MOFs/SiC composite is the best.The pure MOFs/SiC nanocrystals photocatalytic CO₂reduction reaction after 15 hours of CO production is only 15μmol g^-1.（2）Taking MOFs/SiC as the research object,for the first time,MOFs/SiC,a composite nanomaterial with a stable structure,was loaded on the PVA-co-PE nanofiber membrane,and the composite membrane was then introduced into the photocatalytic reduction of CO₂system.Based on the acetonitrile/water/triethanolamine photocatalytic reaction system we designed,under the same light conditions,the CO output in the MOFs/SiC composite nanofiber membrane reached 465μmol g^-1,which was compared with pure MOFs/SiC nanocrystals and composite membranes.The catalytic activity is increased by 31times,and the stability during the photoreaction process is significantly improved.This work confirms that the MOFs/SiC nanofiber membrane material photocatalyst can realize the reduction reaction substrate as a high value-added product in the photocatalytic reduction of CO₂system.（3）Based on the doping strategy,a bimetallic organic framework doped MIL-100（Fe）/MIL-88A（Fe）composite nanocrystalline material was prepared and loaded on the PVA-co-PE nanofiber membrane and used for photocatalysis CO₂reduction system.Compared with the composite nanofiber membrane material of single metal organic framework,bimetal ion doping can not only increase the catalytic active sites of the photocatalytic CO₂reduction system,but also effectively improve the MIL-100（Fe）/MIL-88A（Fe）nano The separation efficiency of photo-generated carriers in the fiber membrane significantly improves the photocatalytic performance.By fine-tuning the doping ratio,the output of the MIL-100（Fe）/MIL-88A（Fe）-based catalyst for photocatalytic reduction of CO₂to CO was increased to 180μmol g^-1.Through a series of characterizations,an in-depth analysis of the internal relationship between the doping rate of bimetallic organic framework and photocatalytic performance has further confirmed that the strategy of improving photocatalytic activity through bimetallic organic framework doping is universal.The photocatalytic performance of organic frameworks and the design of highly efficient and stable nanofiber membrane photocatalysts provide scientific research directions.