Two-dimensional(2D)porphyrin(Por)-based covalent organic frameworks(COFs)provide an attractive and effective strategy for photocatalytic CO_(2)reduction,but the layered structure due toπ–πstacking is challenging fo...Two-dimensional(2D)porphyrin(Por)-based covalent organic frameworks(COFs)provide an attractive and effective strategy for photocatalytic CO_(2)reduction,but the layered structure due toπ–πstacking is challenging for the exposure of active sites and transfer of mass and photogenerated carriers.In this study,a series of 2D conjugated porphyrin-based COFs were prepared using porphyrin blocks with linking units having different degrees of twisting.According to the experimental and theoretical calculation results,owing to the large spatial steric hindrance between the two carbazole units connected by the N–N single bond,a greatly undulating layered structure was formed in NN-Por-COF,which enhanced mass transfer and exposed more catalytic sites.The introduction of carbazole also modulated the electronic structure of the porphyrin Co center,which lowered the reaction energy barrier.The optimization of the structural and electronic effects led to the excellent photocatalytic CO_(2)reduction performance of NN-Por-COF,with CO conversion rates as high as 22.38 and 3.02 mmol g−1 h−1 under pure and diluted(10%)CO_(2)atmosphere,respectively,which are superior to those of most of the reported porphyrin-based photocatalysts.展开更多
Electrochemical CO_(2)reduction is a viable,economical,and sustainable method to transform atmospheric CO_(2)into carbon-based fuels and effectively reduce climate change and the energy crisis.Constructing robust cata...Electrochemical CO_(2)reduction is a viable,economical,and sustainable method to transform atmospheric CO_(2)into carbon-based fuels and effectively reduce climate change and the energy crisis.Constructing robust catalysts through interface engineering is significant for electrocatalytic CO_(2)reduction(ECR)but remains a grand challenge.Herein,SnO2/Bi_(2)O_(2)CO_(3)heterojunction on N,S-codoped-carbon(SnO_(2)/BOC@NSC)with efficient ECR performance was firstly constructed by a facile synthetic strategy.When the SnO_(2)/BOC@NSC was utilized in ECR,it exhibits a large formic acid(HCOOH)partial current density(JHCOOH)of 86.7 mA·cm^(−2)at−1.2 V versus reversible hydrogen electrode(RHE)and maximum Faradaic efficiency(FE)of HCOOH(90.75%at−1.2 V versus RHE),respectively.Notably,the FEHCOOH of SnO_(2)/BOC@NSC is higher than 90%in the flow cell and the JHCOOH of SnO_(2)/BOC@NSC can achieve 200 mA·cm^(−2)at−0.8 V versus RHE to meet the requirements of industrialization level.The comparative experimental analysis and in-situ X-ray absorption fine structure reveal that the excellent ECR performance can be ascribed to the synergistic effect of SnO_(2)/BOC heterojunction,which enhances the activation of CO_(2)molecules and improves electron transfer.This work provides an efficient SnO_(2)-based heterojunction catalyst for effective formate production and offers a novel approach for the construction of new types of metal oxide heterostructures for other catalytic applications.展开更多
基金supported by the National Natural Science Foundation of China(22235001,22175020,and 22271012)the Fundamental Research Funds for the Central Universities(FRF-IDRY-23-021,FRF-BR-23-02B,and FRF-TP-24-014A)+1 种基金University of Science and Technology Beijingsupported by the User Experiment Assist System of Shanghai Synchrotron Radiation Facility.
文摘Two-dimensional(2D)porphyrin(Por)-based covalent organic frameworks(COFs)provide an attractive and effective strategy for photocatalytic CO_(2)reduction,but the layered structure due toπ–πstacking is challenging for the exposure of active sites and transfer of mass and photogenerated carriers.In this study,a series of 2D conjugated porphyrin-based COFs were prepared using porphyrin blocks with linking units having different degrees of twisting.According to the experimental and theoretical calculation results,owing to the large spatial steric hindrance between the two carbazole units connected by the N–N single bond,a greatly undulating layered structure was formed in NN-Por-COF,which enhanced mass transfer and exposed more catalytic sites.The introduction of carbazole also modulated the electronic structure of the porphyrin Co center,which lowered the reaction energy barrier.The optimization of the structural and electronic effects led to the excellent photocatalytic CO_(2)reduction performance of NN-Por-COF,with CO conversion rates as high as 22.38 and 3.02 mmol g−1 h−1 under pure and diluted(10%)CO_(2)atmosphere,respectively,which are superior to those of most of the reported porphyrin-based photocatalysts.
基金supported by the National Natural Science Foundation of China(Nos.21631003 and 22001015)the Fundamental Research Funds for the Central Universities(No.2050205)University of Science and Technology Beijing.
文摘Electrochemical CO_(2)reduction is a viable,economical,and sustainable method to transform atmospheric CO_(2)into carbon-based fuels and effectively reduce climate change and the energy crisis.Constructing robust catalysts through interface engineering is significant for electrocatalytic CO_(2)reduction(ECR)but remains a grand challenge.Herein,SnO2/Bi_(2)O_(2)CO_(3)heterojunction on N,S-codoped-carbon(SnO_(2)/BOC@NSC)with efficient ECR performance was firstly constructed by a facile synthetic strategy.When the SnO_(2)/BOC@NSC was utilized in ECR,it exhibits a large formic acid(HCOOH)partial current density(JHCOOH)of 86.7 mA·cm^(−2)at−1.2 V versus reversible hydrogen electrode(RHE)and maximum Faradaic efficiency(FE)of HCOOH(90.75%at−1.2 V versus RHE),respectively.Notably,the FEHCOOH of SnO_(2)/BOC@NSC is higher than 90%in the flow cell and the JHCOOH of SnO_(2)/BOC@NSC can achieve 200 mA·cm^(−2)at−0.8 V versus RHE to meet the requirements of industrialization level.The comparative experimental analysis and in-situ X-ray absorption fine structure reveal that the excellent ECR performance can be ascribed to the synergistic effect of SnO_(2)/BOC heterojunction,which enhances the activation of CO_(2)molecules and improves electron transfer.This work provides an efficient SnO_(2)-based heterojunction catalyst for effective formate production and offers a novel approach for the construction of new types of metal oxide heterostructures for other catalytic applications.
