摘要
随着现代工业的飞速发展,如何实现氮氧化物的有效脱除成为目前亟待解决的重要难题.本研究提出了一种在石墨相氮化碳(g-C3N4)表面原位生长纳米氧化锌点阵构建柱撑结构复合材料策略,以实现在可见光下光氧化去除NO.通过离子吸附反应,成功制备了不同氧化锌颗粒负载量的ZnO NP/g-C3N4柱撑结构复合光氧化剂,并对其结构和电子特性进行了研究.结果表明,氧化锌纳米颗粒(ZnONP)的引入改善了 g-C3N4的团聚,提高了比表面积,暴露出更多活性位点.异质结构的构建改善了复合材料能带结构,促进了光生载流子的迁移及分离,光氧化性能显著提升.在可见光照射下质量分数为2.5％的ZnO NP/g-C3N4样品展现出了优异的光氧化性能,对NO体积分数为3×10-5％以下的混合空气光氧化去除表现出优良的高效稳定性.本研究为高性能光氧化剂的设计与构建提供了有效策略,并为消除工业NO污染物提供了技术参考.
Abstract
With the rapid industrial development,air pollution and global climate change have become pressing issues.Addressing the effective removal of nitrogen oxides(NOx),a major contributor to these problems,is crucial.Photo-oxidation technology emerges as a promising solution,offering a new,green method of NOx removal.This technology stands out for its safety,cost-effectiveness,cleanliness,and cycle stability,making it an efficient approach to tackling NOx emissions.In this study,we explore a novel strategy that involves the in-situ growth of ZnO nanodot arrays on surfaces of graphite-phase carbon nitride(g-C3N4)to construct column-supported structure composites.These composites are designed for the photo-oxidation removal of NO under visible light.By employing an ion adsorption reaction,ZnO NP/g-C3N4 column-supported structure composite photo-oxidizers were successfully synthesized with varying ZnO particle mass fractions of 1％,2.5％,and 5％,respectively.The investigation revealed that introducing ZnO NP significantly increases the specific surface area of the ZnO NP/g-C3N4 composites compared to pure g-C3N4 samples,which have a specific surface area of 31.092 m2·g-1.Specifically,the 2.5％ZnO NP/g-C3N4 composites exhibited a substantial increase to 58.063 m2·g-1,while the 1％and 5％ZnO NP/g-C3N4 composites reached 37.141 m2·g-1 and 42.563 m2·g-1,respectively.This enhancement in the specific surface area,attributed to the columnar support structure,addresses the stacking issue of the g-C3N4 lamellae in the composites.The resulting structure is stretchier and fluffier,exposing a greater number of reactive sites.Furthermore,the construction of a heterostructure improves the energy band structure of the composites,facilitating the migration and separation of photogenerated carriers,which significantly enhances the photo-oxidation performance.During the NO photo-oxidation removal experiments,the ZnO NP/g-C3N4 composites demonstrated a marked improvement in photo-oxidation efficiency compared to pure g-C3N4.Notably,the 2.5％ZnO NP/g-C3N4 composites achieved a 100％photo-oxidation removal rate of NO,maintaining an effective removal performance across different NO concentrations and exhibiting robust performance in five cycles of stability tests.This study provides an effective strategy for designing and constructing high-performance photo-oxidizers and provides a technical reference for eliminating industrial NO pollutants.In addition,our study introduces a method for the photo-oxidation removal of NO and inspires new approaches in the design and synthesis of composite photocatalysts.By modulating the composition and structure of these composites,their photo-oxidation performance can be further optimized to achieve more efficient and stable pollutant removal.This advancement holds significant implications for environmental protection and sustainable development.
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