TiO_(2)/TiN纳米管异质结用于光电催化CO_(2)还原:氮辅助活性氢机制  

Photoelectrocatalytic reduction of CO_(2)catalyzed by TiO_(2)/TiN nanotube heterojunction:Nitrogen assisted active hydrogen mechanism

作　　者：魏艳 段睿智 张巧兰 曹有智 王金圆 王冰 万雯瑞 刘春燕 陈加藏 高红 景欢旺[1,2,4] Yan Wei;Ruizhi Duan;Qiaolan Zhang;Youzhi Cao;Jinyuan Wang;Bing Wang;Wenrui Wan;Chunyan Liu;Jiazang Chen;Hong Gao;Huanwang Jing(State Key Laboratory of Applied Organic Chemistry,College of Chemistry and Chemical Engineering,Lanzhou University,Lanzhou 730000,Gansu,China;Key Laboratory of Advanced Catalysis,Gansu Province,State Key Laboratory of Applied Organic Chemistry,College of Chemistry and Chemical Engineering,Lanzhou University,Lanzhou 730000,Gansu,China;State Key Laboratory of Catalysis,Dalian Institute of Chemical Physics,Chinese Academy of Sciences,Dalian National Laboratory for Clean Energy,Dalian 116023,Liaoning,China;State Key Laboratory of Coal Conversion,Institute of Coal Chemistry,Chinese Academy of Sciences,Taiyuan 030001,Shanxi,China)

机构地区：[1]兰州大学化学化工学院,功能有机分子化学国家重点实验室,甘肃兰州730000 [2]兰州大学化学化工学院,甘肃省先进催化中心,功能有机分子化学国家重点实验室,甘肃兰州730000 [3]中国科学院大连化学物理研究所,催化基础国家重点实验室,辽宁大连116023 [4]中国科学院山西煤炭化学研究所,煤转化国家重点实验室,山西太原030001

出　　处：《Chinese Journal of Catalysis》2023年第4期243-253,共11页催化学报（英文）

基　　金：甘肃省自然科学基金(21JR7RA466);煤转化国家重点实验室开放基金(J21-22-913);中央高校基本科研业务费(lzujbky-2021-sp55).

摘　　要：利用太阳能将CO_(2)转换为高附加值的化学品是解决化石燃料消耗过快与CO_(2)排放过度问题的可行性方案.光电催化CO_(2)还原可以模拟自然光合作用将CO_(2)还原为多碳产物(C^(2+)).然而,光电催化剂的带隙与太阳辐射光谱不匹配以及载流子的快速复合是限制人工光合作用效率的关键因素.前期研究表明,缺陷工程可有效地增加催化剂活性位点,减小半导体的带隙并增强对光子的捕获能力;而异质结的构筑则可有效提升载流子的分离效率.因此,构建具有较好可见光响应的高效半导体异质结催化剂有望实现催化材料对CO_(2)还原能力和产物选择性的提升.本文通过对金属钛板进行电化学阳极氧化,氨气气氛煅烧得到TiN,然后原位进行部分氧化构筑出结构新颖的TiO_(2)/TiN纳米管异质结材料,再进行配体和钯量子点修饰,得到更加高效的催化电极材料Pd/R-TiO_(2)/TiN,并在三电极系统中研究了其光电催化CO_(2)还原的性能.通过扫描隧道电子显微镜、透射电子显微镜、X射线粉末衍射、X射线光电子能谱、电子顺磁共振谱、X射线吸收近边结构光谱及莫特肖特基曲线等系统考察了催化剂的结构与光电催化性能,证明了n-n同型异质结的成功构筑,且纳米管状的异质结含有丰富的Ti^(3+)和氧空位,具有较好的太阳光捕获能力,保留了间隙金属材料TiN良好的电荷传输能力,提高了光生载流子的分离效率.光电催化CO_(2)还原结果表明,纳米管状Pd/R-TiO_(2)/TiN异质结材料具有较好的CO_(2)还原能力.其中Pd/R-TiO_(2)/TiN-30电极的碳基化合物的产率高达115.9μmolL^(–1)h^(-1)cm^(-2),是纳米颗粒状Pd/R-TiO_(2)/TiN-30异质结材料的2.2倍,且具有最高的C_(2)选择性(65.7%),说明纳米管状结构为反应提供的有限空间有利于C–C耦联.另外,光电联合催化的产率是纯光催化的3.4倍,纯电催化的3.3倍,说明光电协同催化的重要作用.此外,�To address the over‐emission of CO_(2),the construction of new heterojunction materials is a promising approach for the photoelectrocatalytic(PEC)conversion of CO_(2)into valuable chemicals.Herein,a series of heterojunctions of TiO_(2)/TiN nanotube arrays were designed and fabricated by anodic oxidation of titanium plates,followed by in situ partial oxidation to form heterojunctions.The surface of the heterojunction with nitrogen instead of oxygen contained more active Ti3+species,and the oxygen vacancies were able to harvest solar light and showed excellent performance in the PEC reduction of CO_(2).As a porous material,the TiO_(2)/TiN nanotube supports good adsorption of CO_(2)as well as a confined space favoring C–C coupling.Operando Fourier transform infrared(FTIR)analysis revealed that the active species*COOḢand*CHO were the major intermediates.Density functional theory(DFT)calculations revealed that the highly active hydrogen atoms could attach to the surface of the heterojunction to form Ti–H species with Ti^(3+),and the existence of nitrogen atoms could promote the migration of lattice oxygen to form new oxygen vacancies,which is conducive to the adsorption and coupling of CO_(2)and intermediates.The vibration frequency of Ti–H predicted by DFT calculations matches well with the operando FTIR observations.The PEC cell of Pd/R‐TiO_(2)/TiN‐30|SCE|BiVO_(4)efficiently produced carbon‐based chemicals at a rate of 115.9μmol L^(-1)h^(-1)cm^(-2)with high selectivity for C_(2)products.The total efficiency of the PEC cell approached 6.0%,exceeding that of the plant cell by 0.4%.Isotopic labeling experiments of^(13)CO_(2)and H_(2)^(18)O verified the elemental source and inferred the reaction pathway via highly active hydrogen.

关 键 词：光电催化 CO_(2)还原 异质结 氮化钛 原位红外 

分 类 号：O643.36[理学—物理化学] TB383.1[理学—化学] X701[一般工业技术—材料科学与工程]