高选择性H_(2)O_(2)光合成:Ba原子注入面内高度有序结晶结构的g-C_(3)N_(4)纳米棒  

Towards highly‐selective H_(2)O_(2) photosynthesis:In‐plane highly ordered carbon nitride nanorods with Ba atoms implantation

作　　者：孟爱云 马辛源 温达 钟威 周双 苏耀荣 Aiyun Meng;Xinyuan Ma;Da Wen;Wei Zhong;Shuang Zhou;Yaorong Su(College of New Materials and New Energies,Shenzhen Technology University,Shenzhen 518118,Guangdong,China)

机构地区：[1]深圳技术大学新材料与新能源学院,广东深圳518118

出　　处：《Chinese Journal of Catalysis》2024年第5期231-241,共11页催化学报（英文）

基　　金：国家自然科学基金(22178224,22272110,22002091);深圳技术大学基本科研业务费(20211063010047);广东省基础与应用基础研究基金(2020A1515110873,2023A1515110535);深圳市科技计划(20231127203830001).

摘　　要：过氧化氢(H_(2)O_(2))是一种重要的绿色氧化剂,在医疗、军工、食品和绿色化学合成等领域有着广泛应用.然而,传统蒽醌法合成H_(2)O_(2)存在能耗高、污染严重等问题.光催化合成H_(2)O_(2)技术,利用来源丰富的太阳能实现氧气的两电子还原,被认为是替代蒽醌工艺的理想方案.石墨相氮化碳(g-C_(3)N_(4))因具有成本低、化学性质稳定和电子结构易调等优点,在光催化合成H_(2)O_(2)方面展现出很大潜力.但传统g-C_(3)N_(4)的面内结晶度低,且对两电子氧还原反应的选择性差,这极大地限制了其光合成H_(2)O_(2)效率.为解决这一难题,本文合理设计了一种新策略:将钡(Ba)原子注入面内高度有序结晶结构的g-C_(3)N_(4)纳米棒(BI-CN),在增强g-C_(3)N_(4)的面内结晶度的同时,进一步提高其对两电子氧还原反应的选择性.本文采用BaCl2诱导的面内聚合策略,实现了Ba原子注入的面内高度有序结晶结构g-C_(3)N_(4)纳米棒的可控合成.在合成过程中,三聚氰胺分子选择性地吸附在BaCl2的(200)晶面,并与暴露在BaCl2表面的Ba原子形成Ba-N键.这种强相互作用诱导了三嗪结构单元的定向富集和聚合,从而形成面内有序结晶结构的g-C_(3)N_(4)结构.同时,Ba原子通过Ba-N键稳定地锚定在g-C_(3)N_(4)结构中,构建了Ba原子注入的面内高度有序结晶结构的g-C_(3)N_(4)纳米棒.实验和理论计算结果表明,由于Ba原子和N原子的电负性差异,电子从Ba原子迁移到N原子,形成缺电子的Ba活性位点.注入的Ba原子起到正电荷中心的作用,氧气分子以Pauling构型稳定地吸附在Ba原子上,该吸附构型使得O-O键不易断裂并增强了*OOH中间体的稳定性,从而抑制了四电子氧还原生成水的反应,有效地提高了两电子氧还原的选择性,最终实现高效的光催化H_(2)O_(2)合成.其中,最优的BI-CN3(三聚氰胺和BaCl2质量比为9:2)光催化生成H_(2)O_(2)的速率达到353μmol L^(-1) h^(-1),是原Graphitic carbon nitride(g-C_(3)N_(4))shows great potential in photocatalytic H_(2)O_(2) production.However,challenges arise from its low in-plane crystallinity and selectivity in two-electron oxygen reduction reaction(2e–-ORR),greatly limiting its H_(2)O_(2) photosynthesis efficiency.Herein,we develop an ingenious strategy to simultaneously increase the in-plane crystallinity and induce the highly-selective 2e–-ORR by rationally designing barium(Ba)atom-implanted in-plane highly ordered g-C_(3)N_(4) nanorods.The approach involves controllable synthesis of in-plane high crystallinity g-C_(3)N_(4) nanorods with Ba implantation(BI-CN)using a BaCl2-mediated in-plane polymerization strategy.The unique Ba-N interaction induces the oriented polymerization of 3-s-triazine units to form well-arranged in-plane structures.Experimental and theoretical calculations clarify that the implanted Ba atoms function as positive charge centers,resulting in a Pauling-type O_(2) adsorption configuration.This minimizes O–O bond breaking energy,thus suppressing the four-electron oxygen reduction reaction(4e–-ORR)and facilitating a highly-selective 2e–-ORR pathway for efficient photocatalytic H_(2)O_(2) production.Consequently,the optimized BI-CN3 photocatalyst exhibits an outstanding H_(2)O_(2) production rate of as high as 353μmol L^(–1) h^(–1),surpassing the pristine g-C_(3)N_(4) by 6.1 times.This study concurrently optimizes the in-plane crystallinity and O_(2) adsorption sites of g-C_(3)N_(4) photocatalysts for highly-selective H_(2)O_(2) production,providing innovative insights for designing efficient photocatalysts with diverse applications.

关 键 词：H_(2)O_(2)光合成 石墨相氮化碳 Ba原子注入 高选择性两电子氧还原 面内高结晶度 

分 类 号：TQ116.2[化学工程—无机化工] O643.36[理学—物理化学] O644.1[理学—化学]