易回收碳纤维/g-C_(3)N_(4)纳米片阵列制备及光催化和光电催化研究

Flexible carbon-fiber/g-C_(3)N_(4) nanosheet arrays as recyclable photocatalysts and photoelectrocatalysts

在光催化降解领域,粉末g-C_(3)N_(4)光催化材料使用后在流体中分离和回收困难,同时也会产生二次污染。在氩气保护下,采用化学气相沉积法在三维碳纤维织物表面沉积g-C_(3)N_(4)纳米片,从而制备了易回收碳纤维/g-C_(3)N_(4)纳米片阵列光催化材料,研究了碳纤维/g-C_(3)N_(4)纳米片阵列的光学、电化学和光电催化性能。结果表明,g-C_(3)N_(4)纳米片可以吸收可见光产生光生电子和空穴,而碳纤维良好的导电性提高了易回收碳纤维/g-C_(3)N_(4)纳米片阵列光催化材料中光生电子/空穴的分离效率。降解240 min,易回收碳纤维/g-C_(3)N_(4)纳米片阵列光催化材料的电催化、光催化和光电催化对2,4-二硝基酚的降解率分别为20.7%、33.5%和99.5%。在光电催化过程中,外加偏电压加速了光生电子向阴极迁移,进一步提高了光生电子/空穴分离效率,使电催化和光催化存在协同效应。将粉末光催化材料与柔性碳纤维织物组合,提供了一种新的光催化材料组装方式,极大降低了粉末光催化材料的分离和回收成本。

In the field of photocatalytic degradation,the separation and recycle technology of powdery g-C_(3)N_(4)after usage has not been mature,which causes secondary pollution problems for large-scale industrial applications.In this paper,carbon-fiber/g-C_(3)N_(4)nanosheet arrays were fabricated by chemical vapor deposition(CVD)under argon protec⁃tion,and the optical,electrochemical and photocatalytic performance of carbon-fiber/g-C_(3)N_(4)nanosheet arrays were studied.The results indicated that carbon-fiber/g-C_(3)N_(4)nanosheet arrays generated photon-excited electrons and holes under visible light irradiation during photocatalytic process.The excellent electrical conductivity of carbon fi⁃ber could trap photon-excited electrons in conduction band of g-C_(3)N_(4)nanosheet and creat holes in valence band of g-C_(3)N_(4)nanosheet.20.7%,33.5%and 99.5%of 2,4-dinitrophenol were degraded by photocatalysis,electrocatalysis and photoelectrocatalysis of carbon-fiber/g-C_(3)N_(4)nanosheet arrays within 240 min.The external voltage further en⁃hanced the separation of photo-generated electrons and holes,which made the photoelectrocatalysis of carbon-fiber/g-C_(3)N_(4)nanosheet arrays exerted unexpected performance through synergistic interactions of photocatalysis and elec⁃trocatalysis.The assembly of powdery photocatalysts and carbon fibers textile might provide a general methodology in the design of separable and recyclable photocatalysts with broad applications in environment-related fields.The assembly strategy developed herein significantly reduced the separable and recyclable cost of powdery photocata⁃lysts and offered valuables references for industrial application of photocatalysis and photoelectrocatalysis.