摘要
光催化CO_(2)还原是实现CO_(2)绿色转化利用的重要途径之一,但一直受其反应转化效率低的制约。开发新的CO_(2)还原反应体系和提高光催化剂的可见光利用率及光生电子与空穴的分离效率是解决上述问题的有效方法。本文利用甲苯作为底物,构建了光催化CO_(2)-甲苯耦合反应的新体系,并通过静电组装法合成了Ti_(1)Li_(3)Al_(2)-层状双氢氧化物(LDHs)/石墨相氮化碳(g-C_(3)N_(4))复合光催化剂。重点研究了该复合光催化剂的光电性质及在CO_(2)-甲苯耦合反应体系中的光催化反应特性。结果表明,在光催化CO_(2)-甲苯耦合体系中,Ti_(1)Li_(3)Al_(2)-LDHs/g-C_(3)N_(4)作用下,CO_(2)被还原为CO,甲苯被氧化为苯甲醇、苯甲醛及苯甲酸苄酯,其中苯甲醛和苯甲醇的含量可达到4.80和4.70 mmol/gcat。这主要归因于Ti_(1)Li_(3)Al_(2)-LDHs/g-C_(3)N_(4)中,g-C_(3)N_(4)将Ti_(1)Li_(3)Al_(2)-LDHs在紫外区的吸收扩展到了可见光区,并提高了Ti_(1)Li_(3)Al_(2)-LDHs的分散性,从而为光催化反应提供更多的活性位点;Ti_(1)Li_(3)Al_(2)-LDHs/g-C_(3)N_(4)的界面处形成了S型异质结,有利于界面处的光生电子的转移,提高了其光生电子与空穴的分离效率,而甲苯可作为有机底物加快空穴的消耗速度促进了CO_(2)还原反应的进行。为CO_(2)与小分子有机物协同转化提供了一种新思路。
Photocataltyic reduction of CO_(2)is one of the promising routes in CO_(2)conversion and utilization,but the very low CO_(2)conversion rate is the biggest hurdle for the process.Developing a new CO_(2)reduction reaction system and improving the visible light utilization and separation efficiency of photogenerated electrons and holes are effective ways to solve the above problems.In this work,we designed a CO_(2)-toluene coupling reaction system to promote the CO_(2)reduction reaction.The Ti_(1)Li_(3)Al_(2)-layered dihydroxides (LDHs)/graphite phase carbon nitride (gC_(3)N_(4)) composite with heterojunction structure were synthesized by electrostatic assembly method.And the photoelectric property and photocatalytic properties of Ti_(1)Li_(3)Al_(2)-LDHs/g-C_(3)N_(4) composite were explored in CO_(2)-toluene reduction reaction system.The results show that CO_(2)is reduced to CO,and toluene is oxidized to benzyl alcohol,benzaldehyde and benzyl benzoate in the photocataltyic coupling reaction system.Benzaldehyde and benzyl alcohol content can reach 4.80 and 4.70 mmol/gcat.This is mainly because the g-C_(3)N_(4)can extend the absorption of Ti_(1)Li_(3)Al_(2)-LDHs from the ultraviolet region to the visible region,and improve the dispersion of Ti_(1)Li_(3)Al_(2)-LDHs which provide more active sites for photocatalytic reactions.Moreover,the S-type heterojunction is formed in the interface of Ti_(1)Li_(3)Al_(2)-LDHs/g-C_(3)N_(4),which is conducive to the transfer of photogenerated electrons at the interface and improves the separation efficiency of photogenerated electrons and holes.And toluene can be used as an organic substrate to accelerate the rate of hole consumption and stimulate the CO_(2)reduction reaction.This work provides a new idea for the synergistic reaction between CO_(2)reduction and small molecular organics.
作者
马梦丹
周安宁
段飞阳
贾忻宇
凌洁
MA Mengdan;ZHOU Anning;DUAN Feiyang;JIA Xinyu;LING Jie(School of Chemistry and Chemical Engineering,Xi’an University of Science and Technology,Xi’an 710054,China)
出处
《复合材料学报》
EI
CAS
CSCD
北大核心
2023年第3期1522-1533,共12页
Acta Materiae Compositae Sinica
基金
国家自然科学基金(51674194)。
