K原子掺杂高度面间结晶的g-C3N4光催化剂及其高效H2O2光合成
Simultaneously Improving Inter-Plane Crystallization and Incorporating K Atoms in g-C3N4 Photocatalyst for Highly-Efficient H2O2 Photosynthesis
钟威 1郑丹 1欧远新 1孟爱云 1苏耀荣1
作者信息
- 1. 深圳技术大学新材料与新能源学院,广东 深圳 518118
- 折叠
摘要
石墨相氮化碳(g-C3N4)在光催化制备过氧化氢(H2O2)领域有巨大潜力.然而,低的两电子氧还原活性严重限制了g-C3N4的光催化产H2O2效率.在这项研究中,我们通过两步煅烧法在KI晶体表面重新晶化传统g-C3N4材料,合成了钾掺杂的高晶化g-C3N4光催化剂(CN-K).所制备的CN-K光催化材料具有更高的面间结晶度、更窄的禁带宽度和更小的颗粒尺寸(大约20到50 nm).更重要的是,掺入的钾原子作为优异的催化位点可以增强O2吸附和稳定*OOH中间体,从而提高钾掺杂高晶化g-C3N4光催化剂的两电子氧还原活性.其中CN-K(1:6)样品具有显著增强的光催化产H2O2速率(7.8 mmol∙L-1∙h-1),且在420 nm下的表观量子效率为5.17%,光催化活性是传统块状g-C3N4样品的220倍.这项研究不仅揭示了杂原子提高g-C3N4光催化剂两电子氧还原活性的机理,而且为设计高效g-C3N4基光催化剂提供了新的见解.
Abstract
Graphitic carbon nitride(g-C3N4)has gained growing attention in hydrogen peroxide(H2O2)photosynthesis,but the low activity of two-electron oxygen reduction reaction(2e--ORR)still restricts its photocatalytic H2O2-generation performance.Herein,traditional g-C3N4 photocatalysts are recrystallized on KI crystal surfaces by a secondary calcination route to synthesize K incorporated highly-crystalline g-C3N4 photocatalysts.The synthesized CN-K photocatalyst exhibits improved inter-plane crystallization,narrowed bandgap structure,and smaller particle size from 20 to 50 nm.Moreover,the incorporated K atoms,as excellent catalytic sites,can enhance O2 adsorption and stabilize the*OOH intermediates,thus improving the 2e--ORR activity of the K incorporated high-crystallization g-C3N4 photocatalysts.Consequently,the optimized CN-K(1:6)photocatalyst exhibits a remarkably improved H2O2-generation rate of 7.8 mmol·L-1·h-1 with an AQE value of 5.17%at 420 nm,outperforming the traditional g-C3N4 sample by a factor of 220.This work uncovers the roles of heteroatoms in promoting the 2e--ORR selectivity of the g-C3N4 photocatalyst,and offers novel insights to construct highly-active g-C3N4-based materials for H2O2 photosynthesis.
关键词
光催化产H2O2/氮化碳/钾掺杂/高选择性两电子氧还原Key words
Photocatalytic H2O2 evolution/Carbon nitride/K incorporation/Highly-selective 2e--ORR引用本文复制引用
出版年
2024
国家科技期刊平台
NSTL
万方数据