Dipole moment regulation by Ni doping ultrathin Bi_(4)O_(5)Br_(2)for enhancing internal electric field toward efficient photocatalytic conversion of CO_(2)to CO  

Ni掺杂超薄Bi_(4)O_(5)Br_(2)调节偶极矩以增强内部电场促进光催化CO_(2)转化

作　　者：Xiaotian Wang Bo Hu Yuan Li Zhixiong Yang Gaoke Zhang 王小田;胡波;李源;杨直雄;张高科(武汉理工大学矿物资源加工与环境湖北省重点实验室,硅酸盐建筑材料国家重点实验室,湖北武汉430070)

机构地区：[1]Hubei Key Laboratory of Mineral Resources Processing and Environment,State Key Laboratory of Silicate Materials for Architectures,Wuhan University of Technology,Wuhan 430070,Hubei,China

出　　处：《Chinese Journal of Catalysis》2024年第11期257-267,共11页催化学报(英文)

基　　金：国家自然科学基金(92163125);中国国家自然科学基金与俄罗斯科学基金合作研究项目(22361132537)。

摘　　要：The low efficiency of photogenerated carrier separation,and the poor adsorption and activation ability of CO_(2)on the surface of photocatalyst were the key problems to limit the efficiency of photocatalytic CO_(2)reduction.Hence,maximally accelerating the immigration of photogenerated charges d increasing the number of active sites are critical points to boost the overall performance of photocatalytic CO_(2)reduction.However,it is still huge challenge.In this work,the Ni-doped ultrathin Bi_(4)O_(5)Br_(2)nanosheets,which was successfully prepared by hydrothermal and ultrasonic chemical stripping methods,exhibited efficient photocatalytic conversion of CO_(2)to CO.The results of experiments and theoretical calculations indicated that the doped Ni^(2+)significantly increased the crystal dipole moment of Bi_(4)O_(5)Br_(2)in y direction(from 0 to 0.096 e?),which enhanced the polarized electric field strength inside Bi_(4)O_(5)Br_(2),and further promoted the immigration of photogenerated carriers.Meanwhile,the ultrathin structure and doped Ni^(2+)synergistically increased the number of active sites,thereby promoting the adsorption and activation of CO_(2)molecules,as evidenced by experimental and theoretical results collectively.As result,The CO yield was as high as 26.57μmol g–1 h–1 for the prepared Ni-doped ultrathin Bi_(4)O_(5)Br_(2)nanosheets under full spectrum light irradiation,which was 9.48 times that of Bi_(4)O_(5)Br_(2).Therefore,it is of great scientific significance in this study to explore strategies to promote the separation of photogenerated carriers and enhance the adsorption and activation ability of CO_(2)on the surface.传统化石燃料的过度使用使大气中CO_(2)水平上升,从而导致能源问题和温室效应.通过光催化技术将CO_(2)转化为可重复使用的化合物或可再生燃料被认为是解决能源问题和通过直接利用可持续太阳能实现碳中和的一种有前途的策略.然而,光生载流子分离效率低以及CO_(2)在催化剂表面的吸附和活化能力差是制约光催化CO_(2)转化效率的关键问题.因此,最大限度地促进光生载流子的分离和增加活性位点数量对于提高光催化CO_(2)还原的整体性能至关重要.在自发极化作用下,通过在光催化剂表面引入掺杂原子可以调节材料偶极矩进而增强极化电场.该方法不仅能提高电荷分离效率,而且在增强半导体光催化剂对CO_(2)的吸附和活化能力方面也有很大的潜力.本文通过水热法和超声化学剥离法成功制备了Ni掺杂超薄Bi_(4)O_(5)Br_(2)纳米片(UN Ni-BOB)光催化剂.通过X射线粉末衍射和X射线光电子能谱证明了Ni^(2+)离子成功掺杂.采用扫描电镜、透射电镜和原子力显微镜对样品的形貌进行了表征,结果表明UN Ni-BOB为超薄二维结构.瞬态光电流和电阻抗测试分析结果表明,UN Ni-BOB材料具有更好的光生载流子分离效果和更高光电流响应能力,从而实现了光催化活性的显著提高.此外,CO_(2)程序升温脱附测试结合理论计算结果表明,在Bi_(4)O_(5)Br_(2)晶格中引入Ni^(2+)可以有效提高光催化剂对CO_(2)的吸附和活化能力.通过对Ni掺杂Bi_(4)O_(5)Br_(2)前后内部偶极矩计算结果表明,Ni掺杂Bi_(4)O_(5)Br_(2)在三个方向上的电偶极矩都有所增加,并诱导电子发生自旋极化,从而提高了材料中层间极化电场的强度,使得光生载流子能够高效地分离和转移.通过全光谱光照射下的水蒸气耦合光催化CO_(2)还原实验,研究了制备的光催化剂的光催化性能.相较于Bi_(4)O_(5)Br_(2),所合成的超薄Bi_(4)O_(5)Br_(2)纳米片的光催化性能显

关 键 词：Ni-doped Bi_(4)O_(5)Br_(2) Ultra-thin nanomaterial Dipole moment Polarized electric field Photocatalytic CO_(2)reduction 

分 类 号：O643.36[理学—物理化学] O644.1[理学—化学]