S‐Scheme 2D/2D Bi_(2)MoO_(6)/BiOI van der Waals heterojunction for CO_(2) photoreduction  

梯型2D/2D Bi_(2)M_(o)O_(6)/BiOI范德华异质结的制备及CO_(2)光还原性能

作　　者：Zhongliao Wang Bei Cheng Liuyang Zhang Jiaguo Yu Youji Li S.Wageh Ahmed A.Al‐Ghamdi 王中辽;程蓓;张留洋;余家国;李佑稷;S.Wageh;Ahmed A.Al‐Ghamdi(武汉理工大学材料复合新技术国家重点实验室,湖北武汉430070;中国地质大学材料科学与化学学院太阳燃料实验室,湖北武汉430074;吉首大学化学化工学院,湖南吉首416000;阿卜杜勒阿齐兹国王大学理学院物理系,吉达,沙特阿拉伯)

机构地区：[1]State Key Laboratory of Advanced Technology for Materials Synthesis and Processing,Wuhan University of Technology,Wuhan 430070,Hubei,China [2]Laboratory of Solar Fuel,Faculty of Materials Science and Chemistry,China University of Geosciences,Wuhan 430074,Hubei,China [3]College of chemistry and chemical engineering,Jishou University,Jishou 416000,Hunan,China [4]Department of Physics,Faculty of Science,King Abdulaziz University,Jeddah 21589,Saudi Arabia

出　　处：《Chinese Journal of Catalysis》2022年第7期1657-1666,共10页催化学报（英文）

基　　金：国家自然科学基金(51961135303,51872220,51932007,21871217,52073223,U1905215,U1705251).

摘　　要：Reducing CO_(2) to hydrocarbon fuels by solar irradiation provides a feasible channel for mitigating excessive CO_(2) emissions and addressing resource depletion.Nevertheless,severe charge recombi‐nation and the high energy barrier for CO_(2) photoreduction on the surface of photocatalysts com‐promise the catalytic performance.Herein,a 2D/2D Bi_(2)MoO_(6)/BiOI composite was fabricated to achieve improved CO_(2) photoreduction efficiency.Charge transfer in the composite was facilitated by the van der Waals heterojunction with a large‐area interface.Work function calculation demon‐strated that S‐scheme charge transfer is operative in the composite,and effective charge separation and strong redox capability were revealed by time‐resolved photoluminescence and electron para‐magnetic resonance spectroscopy.Moreover,the intermediates of CO_(2) photoreduction were identi‐fied based on the in situ diffuse reflectance infrared Fourier‐transform spectra.Density functional theory calculations showed that CO_(2) hydrogenation is the rate‐determining step for yielding CH_(4) and CO.Introducing Bi_(2)MoO_(6) into the composite further decreased the energy barrier for CO_(2) photoreduction on BiOI by 0.35 eV.This study verifies the synergistic effect of the S‐scheme heterojunction and van der Waals heterojunction in the 2D/2D composite.利用太阳能将CO_(2)还原为具有高能量附加值的含碳气相或液相燃料为解决能源枯竭和气候异常等问题提供一个有前景的方案.然而,由于CO_(2)光还原过程是上坡反应且具有高的反应能垒,目前光催化CO_(2)还原的转化效率仍然很低.为实现高效率CO_(2)光还原,半导体光催化剂需要有宽的光吸收范围、强的氧化还原能力和丰富的活性位点.但同时满足上述条件的光催化剂有限.在半导体中,BiOI具有1.8 eV的窄带隙,可以响应波长大于600 nm的可见光且具有很强的还原能力,因此广泛应用于CO_(2)光还原、全水分解和重金属离子还原等领域.此外,BiOI是一种典型的二维材料,交替的[Bi_(2)O_(2)]^(2+)和I-离子层会导致不同层间产生固有极化和内建电场(IEF).因此,BiOI可以凭借内在的IEF有效地实现电荷分离.然而,CO_(2)光还原还需要质子参与,而质子通常来自水氧化.但BiOI价带的氧化能力不足,影响CO_(2)光还原效率的提升.另一方面,Bi_(2)MoO_(6)也是二维结构,并显示出强氧化能力,在光降解、细菌灭活、分子氧活化、水氧化和水分解等领域被广泛研究.此外,Bi_(2)MoO_(6)具有[Bi_(2)O_(2)]^(2+)和MoO_(4)2-离子层交替的结构,同样可以产生强自发极化和固有IEF.同时,这种二维层状结构有利于形成片状的形貌,这有利于与其他二维材料构建大接触面积的异质结,从而实现电荷的快速输运,并使表面CO_(2)还原反应活性位点增多.本文通过水热法在少层Bi_(2)MoO_(6)纳米片上原位生长BiOI纳米片,设计制备了梯型二维/二维(2D/2D)Bi_(2)MoO_(6)/BiOI范德华异质结复合材料,并用于改进CO_(2)光还原性能.通过功函数、差分电荷密度和X射线光电子能谱证实了Bi_(2)MoO_(6)/BiOI异质结是范德华异质结,且Bi_(2)MoO_(6)和BiOI之间存在梯型的电荷转移机制.通过电子顺磁共振光谱进一步研究了Bi_(2)MoO_(6)/BiOI复合材料的氧化还原能力,结果发现,�

关 键 词：2D/2D S‐scheme heterojunction van der Waals heterojunction CO_(2)photoreduction 

分 类 号：TQ426[化学工程] TB332[一般工业技术—材料科学与工程] X701[环境科学与工程—环境工程]