Edge effect-enhanced CO_(2) adsorption and photo-reduction over g-C_(3)N_(4) nanosheet  

g-C_(3)N_(4)纳米片的边缘效应增强其CO_(2)吸附和光催化还原性能

作　　者：Xuedong Jing Xiaoyun Mi Wei Lu Na Lu Shiwen Du Guodong Wang Zhenyi Zhang 荆雪东;米晓云;鲁巍;吕娜;杜仕文;王国栋;张振翼(长春理工大学材料科学与工程学院,吉林长春130022;大连民族大学国家民委新能源与稀土资源利用重点实验室,辽宁省光敏材料与器件重点实验室,大连市低维半导体光电材料及应用重点实验室,物理与材料工程学院,辽宁大连116600;中科和域(大连)空气系统技术有限公司,辽宁大连116600)

机构地区：[1]School of Material Science and Engineering,Changchun University of Science and Technology,Changchun 130022,Jilin,China [2]Key Laboratory of New Energy and Rare Earth Resource Utilization of State Ethnic Affairs Commission,Key Laboratory of Photosensitive Materials and Devices of Liaoning Province,Dalian Key Laboratory of Low-Dimensional Semiconductor Optoelectronic Materials and Applications,School of Physics and Materials Engineering,Dalian Minzu University,Dalian 116600,Liaoning,China [3]ZOKEURHY(Dalian)Air Systems Technology Co.,Ltd.,Dalian 116600,Liaoning,China

出　　处：《Chinese Journal of Catalysis》2024年第12期112-123,共12页催化学报(英文)

基　　金：国家自然科学基金(22472021,U23A20102,12074055,51772041,62005036);辽宁省“兴辽英才计划”领军人才项目(XLYC_(2)202036);辽宁省“兴辽英才计划”青年拔尖人才项目(XLYC1807176);辽宁省优秀青年科学基金(2022-YQ-13);中央高校基本科研业务费(04442024069);大连市杰出青年科学基金(2018RJ05);辽宁省自然科学基金(2023-MS-132).

摘　　要：Effective CO_(2) adsorption and fast electron injection are two crucial processes of photocatalysts for achieving high-efficiency CO_(2) photo-reduction.However,simultaneously enhancing these processes within a single photocatalyst remains a challenging task.Herein,we propose an intriguing edge effect based on the intrinsic atomic structure of g-C_(3)N_(4) nanosheets(NSs)to enhance their CO_(2) adsorption and facilitate the transfer of photo-generated electrons to the adsorbed CO_(2).By cutting large pieces of g-C_(3)N_(4) NSs into smaller fragments,the exposure of amino groups at the edges of its repeating tri-s-triazine units can be significantly increased.These edge-exposed amino groups serve as active sites for enhancing the CO_(2) capture capacity of g-C_(3)N_(4) NSs.As we decrease the lateral size of g-C_(3)N_(4) NSs from tens of micrometers to hundreds of nanometers,their CO_(2) adsorption capacity increases from 4.74 to 8.56 cm^(3) g^(-1).Reducing the size of g-C_(3)N_(4) NSs also facilitates the transfer of photo-generated electrons to the edge-adsorbed CO_(2).Thus,our optimized g-C_(3)N_(4) NSs with the edge effect exhibits a 37-fold enhancement in activity for CO_(2) photo-reduction compared to normal g-C_(3)N_(4) NSs under simulated sunlight irradiation.Notably,by introducing Pt cocatalysts,we can control product selectivity from 85.9%CO to 97.9%CH_(4).面对全球气候变暖形势的日益严峻,以及对实现碳中和战略目标的迫切需求,半导体光催化技术为将CO_(2)转化为高附加值产品提供了一种切实可行的解决方案.然而,由于CO_(2)分子具有较高的热力学稳定性,其还原反应的动力学过程较为缓慢,传统的半导体光催化剂往往表现出较低的光催化活性和产物选择性.CO_(2)分子的有效吸附和电子的快速注入是实现高效光催化CO_(2)还原过程的两大关键要素.然而,在单一催化剂体系中同时优化这两个过程,仍面临着诸多挑战.本文基于g-C_(3)N_(4)纳米片(NSs)独有的结构特点,提出了一种边缘效应增强光催化CO_(2)还原效率的策略,在增强g-C_(3)N_(4) NSs对CO_(2)吸附能力的同时,有效促进了光生电子向其表面吸附的CO_(2)分子转移,从而成功实现了光催化性能的显著提升.密度泛函理论计算结果表明,g-C_(3)N_(4) NSs边缘部分富含的氨基基团能够有效地吸附CO_(2)分子,且随后的光生电子注入过程也主要在这些边缘位置进行.为同步优化这两个关键过程,采用超声和梯度离心技术对传统热聚合法制备的g-C_(3)N_(4) NSs进行尺寸调控,将其分割成更小的片段.结合扫描电子显微镜、原子力显微镜、X射线光电子能谱和傅里叶红外光谱等结果综合分析,证实了g-C_(3)N_(4) NSs的厚度和横向尺寸的逐渐减少显著增加了边缘氨基的暴露,从而使g-C_(3)N_(4) NSs展现出更强的边缘效应.这些基团作为活性位点,显著增强了g-C_(3)N_(4) NSs对CO_(2)的吸附能力.随着g-C_(3)N_(4) NSs的尺寸从几十微米减小到几百纳米,其对CO_(2)的吸附能力从4.74 cm^(3) g^(-1)显著提升到8.56 cm^(3) g^(-1).同时,g-C_(3)N_(4) NSs尺寸的减小还有利于光生电子注入到吸附在边缘的CO_(2)分子上.在模拟太阳光照射的条件下,经过优化的g-C_(3)N_(4) NSs表现出较好的光催化CO_(2)还原成CO性能,相较于传统热聚合的g-C_(3)N_(4) NSs,催�

关 键 词：PHOTOCATALYSIS CO_(2)reduction CO_(2)adsorption Edge effect Amino group 

分 类 号：O64[理学—物理化学]