Metal-organic frameworks(MOFs)have been tremendously used as photocatalysts for H_(2) generation in recent years.Lacking native active sites(so-called co-catalyst)for H_(2) generation motivates the incorporation of no...Metal-organic frameworks(MOFs)have been tremendously used as photocatalysts for H_(2) generation in recent years.Lacking native active sites(so-called co-catalyst)for H_(2) generation motivates the incorporation of noble metals and their molecular complexes,hydrogenase active site mimics into MOFs to promote H_(2)generation.We herein report an noble-metal-free photocatalytic H_(2) generation system consisting of Erythrosin B dye-sensitized MIL-101(Cr)as a light absorber and Ni(dmgH)_(2) as a co-catalyst.It is found that Ni(dmgH)_(2) can serve as an efficient co-catalyst to boost H_(2) generation in the presence of triethanolamine(TEOA)as an electron donor under visible light irradiation.The optimal MIL-101(Cr)/Ni(dmgH)_(2) hybrid(5 wt%Ni(dmgH)_(2))displays a hydrogen H_(2) rate of 45.5 mmol h^(-1),which is 10 times greater than the control sample without Ni(dmgH)_(2) loading.This paper provides a novel design route for active H_(2) generation systems by combining molecular complexes of earth-abundant metal and MOFs photocatalysts.展开更多
TiO_(2) has been considered as an ideal photocatalyst for water splitting.However,narrow light absorbance,low charge separation efficiency,and rare surface active sites lead to the low photocatalytic efficiency of TiO...TiO_(2) has been considered as an ideal photocatalyst for water splitting.However,narrow light absorbance,low charge separation efficiency,and rare surface active sites lead to the low photocatalytic efficiency of TiO_(2).Although extensive research attempted to improve the situation,there is still lack of method for constructing high active and noble-metal-free TiO_(2) photocatalyst for H_(2) evolution reactions(HER).In this work,we loaded single atomic(SA)Ni(or Co)on the surface of anatase TiO_(2)(TiO_(2)(A))nanosheets by an isolation strategy.Ethylene diamine tetraacetic acid and ethylene glycol(EDTA-EG)compounds were used to chelate metal ions in solution and form carbon quantum dots in the following thermal treatment to isolate the metal ions on surface of TiO_(2)(A).The prepared Ni SA/TiO_(2)(A)catalyst owned a“skin wrapped body”structure with in-situ formed twodimensional(2D)heterojunction facilitating the fast electron transfer.As a result,the Ni SA/TiO_(2)(A)catalyst showed a high H_(2) evolution rate of 2,900μmol·g−1·h−1.This work provides an isolation strategy for constructing promising single-atom metal catalyst for photocatalysis and beyond.展开更多
As an effective means to improve charge carrier separation efficiency and directional transport,the gradient doping of foreign elements to build multi-homojunction structures inside catalysts has received wide attenti...As an effective means to improve charge carrier separation efficiency and directional transport,the gradient doping of foreign elements to build multi-homojunction structures inside catalysts has received wide attentions.Herein,we reported a simple and robust method to construct multi-homojunctions in black TiO_(2) nanotubes by the gradient doping of Ni species through the diffusion of deposited Ni element on the top of black TiO2 nanotubes driven by a high temperature annealing process.The gradient Ni distribution created parts of different Fermi energy levels and energy band structures within the same black TiO_(2) nanotube,which subsequently formed two series of multi-homojunctions within it.This special multi-homojunction structure largely enhanced the charge carrier separation and transportation,while the low concentration of defect states near the surface layer further inhibited carrier recombination and facilitated the surface reaction.Thus,the B-TNT-2Ni sample with the optimized Ni doping concentration exhibited an enhanced hydrogen evolution rate of~1.84 mmol·g^(−1)·h^(−1)under visible light irradiation without the assistance of noble-metal cocatalysts,~four times higher than that of the pristine black TiO_(2)nanotube array.With the capability to create multi-homojunction structures,this approach could be readily applied to various dopant systems and catalyst materials for a broad range of technical applications.展开更多
基金This work was financially supported by the National Natural Science Foundation of China(No.51572003)Anhui Provincial Natural Science Foundation(No.1508085ME105)+1 种基金the Project sponsored by SRF for ROCS,SEMTechnology Foundation for Selected Overseas Chinese Scholar,Ministry of Personnel of China.
文摘Metal-organic frameworks(MOFs)have been tremendously used as photocatalysts for H_(2) generation in recent years.Lacking native active sites(so-called co-catalyst)for H_(2) generation motivates the incorporation of noble metals and their molecular complexes,hydrogenase active site mimics into MOFs to promote H_(2)generation.We herein report an noble-metal-free photocatalytic H_(2) generation system consisting of Erythrosin B dye-sensitized MIL-101(Cr)as a light absorber and Ni(dmgH)_(2) as a co-catalyst.It is found that Ni(dmgH)_(2) can serve as an efficient co-catalyst to boost H_(2) generation in the presence of triethanolamine(TEOA)as an electron donor under visible light irradiation.The optimal MIL-101(Cr)/Ni(dmgH)_(2) hybrid(5 wt%Ni(dmgH)_(2))displays a hydrogen H_(2) rate of 45.5 mmol h^(-1),which is 10 times greater than the control sample without Ni(dmgH)_(2) loading.This paper provides a novel design route for active H_(2) generation systems by combining molecular complexes of earth-abundant metal and MOFs photocatalysts.
基金the Strategic Emerging Industry Development Funds of Shenzhen(No.JCYJ20170817161720484).
文摘TiO_(2) has been considered as an ideal photocatalyst for water splitting.However,narrow light absorbance,low charge separation efficiency,and rare surface active sites lead to the low photocatalytic efficiency of TiO_(2).Although extensive research attempted to improve the situation,there is still lack of method for constructing high active and noble-metal-free TiO_(2) photocatalyst for H_(2) evolution reactions(HER).In this work,we loaded single atomic(SA)Ni(or Co)on the surface of anatase TiO_(2)(TiO_(2)(A))nanosheets by an isolation strategy.Ethylene diamine tetraacetic acid and ethylene glycol(EDTA-EG)compounds were used to chelate metal ions in solution and form carbon quantum dots in the following thermal treatment to isolate the metal ions on surface of TiO_(2)(A).The prepared Ni SA/TiO_(2)(A)catalyst owned a“skin wrapped body”structure with in-situ formed twodimensional(2D)heterojunction facilitating the fast electron transfer.As a result,the Ni SA/TiO_(2)(A)catalyst showed a high H_(2) evolution rate of 2,900μmol·g−1·h−1.This work provides an isolation strategy for constructing promising single-atom metal catalyst for photocatalysis and beyond.
基金support is gratefully acknowledged from the National Natural Science Foundation of China(NSFC)(Nos.62004137,21878257,and 21978196)the Natural Science Foundation(NSF)of Shanxi Province(No.20210302123102)+4 种基金the Key Research and Development Program of Shanxi Province(No.201803D421079)the Scientific and Technological Innovation Programs of Higher Education Institutions in Shanxi(No.2019L0156)the Research Project Supported by Shanxi Scholarship Council of China(No.2020-050)the Fundamental Research Funds for the Central Universities(No.2682021CX116)Sichuan Science and Technology Program(No.2020YJ0259).
文摘As an effective means to improve charge carrier separation efficiency and directional transport,the gradient doping of foreign elements to build multi-homojunction structures inside catalysts has received wide attentions.Herein,we reported a simple and robust method to construct multi-homojunctions in black TiO_(2) nanotubes by the gradient doping of Ni species through the diffusion of deposited Ni element on the top of black TiO2 nanotubes driven by a high temperature annealing process.The gradient Ni distribution created parts of different Fermi energy levels and energy band structures within the same black TiO_(2) nanotube,which subsequently formed two series of multi-homojunctions within it.This special multi-homojunction structure largely enhanced the charge carrier separation and transportation,while the low concentration of defect states near the surface layer further inhibited carrier recombination and facilitated the surface reaction.Thus,the B-TNT-2Ni sample with the optimized Ni doping concentration exhibited an enhanced hydrogen evolution rate of~1.84 mmol·g^(−1)·h^(−1)under visible light irradiation without the assistance of noble-metal cocatalysts,~four times higher than that of the pristine black TiO_(2)nanotube array.With the capability to create multi-homojunction structures,this approach could be readily applied to various dopant systems and catalyst materials for a broad range of technical applications.
