两步焙烧法制备大比表面积和结晶性增强超薄g-C_(3)N_(4)纳米片及其高效光催化产H_(2)O_(2)  

Remarkable Photocatalytic H_(2)O_(2) Production Efficiency over Ultrathin g-C_(3)N_(4) Nanosheet with Large Surface Area and Enhanced Crystallinity by Two-Step Calcination

作　　者：陈恒 聂龙辉 徐凯 杨毅琼 方彩红 Heng Chen;Longhui Nie;Kai Xu;Yiqiong Yang;Caihong Fang(School of Materials and Chemical Engineering,Hubei University of Technology,Wuhan 430068,China)

机构地区：[1]湖北工业大学材料与化学工程学院,武汉430068

出　　处：《物理化学学报》2024年第11期39-40,共2页Acta Physico-Chimica Sinica

基　　金：supported by the Natural Science Foundation of China(51572074);Open Fund of Key Laboratory of Drug Analysis and Anti-drug Technology of the Ministry of Public Security(YNPL-B2021002)。

摘　　要：以水和氧气为原料,光催化产过氧化氢(H_(2)O_(2))具有绿色、清洁的特点而受到广泛关注。针对氮化碳(g-C_(3)N_(4))本征光催化活性低的问题,本文采用两步热聚合法制备了具有大比表面积和结晶性增强的超薄g-C_(3)N_(4)纳米片光催化剂。煅烧条件对g-C_(3)N_(4)的结构属性和催化性能有显著影响。两步焙烧和1℃·min^(-1)最佳升温速率制备的样品(CN-T-1)表现出显著提高的光催化产H_(2)O_(2)效率(3177.0μmol·g^(-1)·h^(-1)),为一步焙烧和1℃·min^(-1)升温速率制备的样品(CN-O-1)(858.6μmol·g^(-1)·h^(-1))的3.7倍,高于文献报导的纯g-C_(3)N_(4)产H_(2)O_(2)效率。CN-T-1在5次循环使用中H_(2)O_(2)产率先略有下降,后基本保持不变,表现出良好的稳定性。相较于CN-O-1,CN-T-1增强的催化性能归因于更大的比表面积、增强的结晶性、更高氧吸附能力和光生载流子分离效率、更长的载流子寿命,以及超薄片层使其具有更大的带隙(3.07 e V,比CN-O-1大+0.26 e V)和更正的价带位置。·O_(2)^(-)自由基被证实为主要的活性物种。CN-T-1光催化产H_(2)O_(2)被证实为两步单电子ORR路径(O_(2)+e^(-)→·O_(2)^(-)→H_(2)O_(2))。The generation of hydrogen peroxide(H_(2)O_(2))from water and oxygen redox reaction by photocatalysis has acquired increasing attention owing to its green and clean properties.Aiming at the low intrinsic photocatalytic activity of carbon nitride(g-C_(3)N_(4)),here,an ultrathin g-C_(3)N_(4) nanosheet photocatalyst with a large surface area and enhanced crystallinity was fabricated by a two-step thermal polymerization technique.The calcination parameters showed a significant impact on the structural properties and catalytic performance of g-C_(3)N_(4).The remarkable H_(2)O_(2) yield(3177.0μmol·g^(-1)·h^(-1))of CN-T-1(by two-step calcination,1℃·min^(-1) optimal heating rate)was 3.7 times that(858.6μmol·g^(-1)·h^(-1))of CN-O-1(by one-step calcination,1℃·min^(-1) heating rate)and higher than those of pure g-C_(3)N_(4) in literature.Most of the H_(2)O_(2) yield for CN-T-1 remained after five cycles,showing good stability.The enhanced catalytic performance of CN-T-1 than CN-O-1 is owing to its larger specific surface area,enhanced crystallinity,higher oxygen adsorption ability and photogenerated carrier separation efficiency,longer lifetime of carriers,and slightly larger bandgap(3.07 eV,+0.26 eV bigger than CN-O-1)with more positive valence band position owing to ultrathin layers.The·O_(2)^(-)radicals were verified to be the primary active species.A two-step single electron ORR pathway(O_(2)+e^(-)→·O_(2)^(-)→H_(2)O_(2))was confirmed for H_(2)O_(2) production over CN-T-1.

关 键 词：光催化 H_(2)O_(2)制备 g-C_(3)N_(4)纳米片 光催化机理 

分 类 号：O643[理学—物理化学]