物理化学学报2021，Vol.37Issue(8)：130-138,9.DOI:10.3866/PKU.WHXB202010073
二维/二维FeNi-LDH/g-C3N4复合光催化剂用于促进CO2光还原反应
2D/2D FeNi-LDH/g-C3N4 Hybrid Photocatalyst for Enhanced CO2 Photoreduction
摘要
Abstract
Photocatalytic reduction of carbon dioxide into chemical fuels is a promising route to generate renewable energy and curtail the greenhouse effect.Therefore,various photocatalysts have been intensively studied for this purpose.Among them,g-C3N4,a 2D metal-free semiconductor,has been a promising photocatalyst because of its unique properties,such as high chemical stability,suitable electronic structure,and facile preparation.However,pristine g-C3N4 suffers from low solar energy conversion efficiency,owing to its small specific surface area and extensive charge recombination.Therefore,designing g-C3N4 (CN) nanosheets with a large specific surface area is an effective strategy for enhancing the CO2 reduction performance.Unfortunately,the performance of CN nanosheets remains moderate due to the aforementioned charge recombination.To counter this issue,loading a cocatalyst (especially a two-dimensional (2D) one) can enable effective electron migration and suppress electron-hole recombination during photo-irradiation.Herein,CN nanosheets with a large specific surface area (97 m2·g-1) were synthesized by a two-step calcination method,using urea as the precursor.Following this,a 2D/2D FeNi-LDH/g-C3N4 hybrid photocatalyst was obtained by loading a FeNi layered double hydroxide (FeNi-LDH) cocatalyst onto CN nanosheets by a simple hydrothermal method.It was found that the production rate of methanol from photocatalytic CO2 reduction over the FeNi-LDH/g-C3N4 composite is significantly higher than that of pristine CN.Following a series of characterization and analysis,it was demonstrated that the FeNi-LDH/g-C3N4 composite photocatalyst exhibited enhanced photo-absorption,which was ascribed to the excellent light absorption ability of FeNi-LDH.The CO2 adsorption capacity of the FeNi-LDH/g-C3N4 hybrid photocatalyst improved,owing to the large specific surface area and alkaline nature of FeNi-LDH.More importantly,the introduction of FeNi-LDH on the CN nanosheet surface led to the formation of a 2D/2D heterojunction with a large contact area at the interface,which could promote the interfacial separation of charge carriers and effectively inhibit the recombination of the photogenerated electrons and holes.This subsequently resulted in the enhancement of the CO2 photo-reduction activity.In addition,by altering the loading amount of FeNi-LDH for photocatalytic performance evaluation,it was found that the optimal loading amount was 4％ (w,mass fraction),with a methanol production rate of 1.64 μmol·h-1·g-1 (approximately 6 times that of pure CN).This study provides an effective strategy to improve the photocatalytic CO2 reduction activity of g-C3N4 by employing 2D layered double hydroxide as the cocatalyst.It also proposes a protocol for the successful design of 2D/2D photocatalysts for solar energy conversion.关键词
光催化/二维/二维异质结/层状双氢氧化物/太阳能转化/电荷转移Key words
Photocatalysis/2D materials/Layered double hydroxide/Solar energy conversion/Charge transfer分类
化学化工引用本文复制引用
李瀚,李芳,余家国,曹少文..二维/二维FeNi-LDH/g-C3N4复合光催化剂用于促进CO2光还原反应[J].物理化学学报,2021,37(8):130-138,9.基金项目
The authors acknowledge the financial support from the National Natural Science Foundation of China (51922081,21773179,51961135303,51932007,U1705251) and the National Key Research and Development Program of China (2018YFB1502001),the Natural Science Foundation of Hubei Province of China (2017CFA031),and the Fundamental Research Funds for the Central Universities,China (WUT:2019-Ⅲ-196,2020-YB-010).国家自然科学基金(51922081,21773179,51961135303,51932007,U1705251),国家重点研发计划(2018YFB1502001),湖北省自然科学基金(2017CFA031)和中央高校基本科研业务费(WUT:2019-Ⅲ-196,2020-YB-010)资助 （51922081,21773179,51961135303,51932007,U1705251）
