The direct conversion of methane into methanol under mild conditions represents a highly appealing pathway.Regulating the generation of hydroxyl radicals(·OH)is a representative method,but excessive release of...The direct conversion of methane into methanol under mild conditions represents a highly appealing pathway.Regulating the generation of hydroxyl radicals(·OH)is a representative method,but excessive release of·OH will inevitably lead to the over-oxidation of CH3OH.Here,we design AgPd alloy and Co3O4 cascade active sites on the TiO2 surface(AgPd-Co/TiO2)to control the release rate of·OH to improve the selectivity of CH3OH.By incorporating Co3O4 as a hole buffer and storage center,the kinetics of·OH generation at the TiO2 interface can be effectively modulated.This confines the spatial distribution of·OH to the active sites of the AgPd alloy,thus facilitating the directional combination of·CH3 and·OH.The optimal AgPd-Co/TiO2 photocatalyst demonstrates outstanding catalytic performance with the selectivity of CH3OH reaching up to 93%in the liquid phase.AgPd-Co/TiO2 exhibited significantly enhanced selectivity relative to reported TiO2-based photocatalytic systems,while simultaneously achieving comparable methanol yields.This research offers valuable insights for the precise design of composite photocatalysts to achieve highly selective methane oxidation.展开更多
Constructing step-scheme(S-scheme)heterojunctions has been confirmed as a promising strategy for enhancing the photocatalytic activity of composite materials.In this work,a series of sulfur-doped g-C3N4(SCN)/TiO2 S-sc...Constructing step-scheme(S-scheme)heterojunctions has been confirmed as a promising strategy for enhancing the photocatalytic activity of composite materials.In this work,a series of sulfur-doped g-C3N4(SCN)/TiO2 S-scheme photocatalysts were synthesized using electrospinning and calcination methods.The as-prepared SCN/TiO2 composites showed superior photocatalytic performance than pure TiO2 and SCN in the photocatalytic degradation of Congo Red(CR)aqueous solution.The significant enhancement in photocatalytic activity benefited not only from the 1D well-distributed nanostructure,but also from the S-scheme heterojunction.Furthermore,the XPS analyses and DFT calculations demonstrated that electrons were transferred from SCN to TiO2 across the interface of the SCN/TiO2 composites.The built-in electric field,band edge bending,and Coulomb interaction synergistically facilitated the recombination of relatively useless electrons and holes in hybrid when the interface was irradiated by simulated solar light.Therefore,the remaining electrons and holes with higher reducibility and oxidizability endowed the composite with supreme redox ability.These results were adequately verified by radical trapping experiments,ESR tests,and in situ XPS analyses,suggesting that the electron immigration in the photocatalyst followed the S-scheme heterojunction mechanism.This work can enrich our knowledge of the design and fabrication of novel S-scheme heterojunction photocatalysts and provide a promising strategy for solving environmental pollution in the future.展开更多
In this work,we designed and prepared the novel TiO2@ZnIn2 S4 nano-sized hollow structure via templating method assisted by hydrothermal synthesis process.Its unique hollow structure and type-II heterojunction between...In this work,we designed and prepared the novel TiO2@ZnIn2 S4 nano-sized hollow structure via templating method assisted by hydrothermal synthesis process.Its unique hollow structure and type-II heterojunction between TiO2 hollow nanospheres and ZnIn2 S4 nanosheet can provide enough interior cavities and transfer paths for the light absorption and charge quick migration.The crystal structure,morphology and charges separation property were measured.The characterization results show that the hollow-structured Ti O2@ZnIn2 S4 was successfully prepared,and the optimal sample exhibited excellent photocatalytic hydrogen generation compared with TiO2/ZnIn2 S4 cluster exceeding by a factor of 1.1 under overall light irradiation.Specially,the detailed mechanism of the photocatalytic H2 evolution and charge carrier migration for the as-prepared TiO2@ZnIn2 S4 hollow nanosphere was also studied.展开更多
Modern communication technologies put forward higher requirements for electromagnetic wave(EMW)absorption materials.Metal-organic framework(MOF)derivatives have been widely concerned with its diverse advantages.To bre...Modern communication technologies put forward higher requirements for electromagnetic wave(EMW)absorption materials.Metal-organic framework(MOF)derivatives have been widely concerned with its diverse advantages.To break the mindset of magneticderivative design,and make up the shortage of monometallic non-magnetic derivatives,we first try non-magnetic bimetallic MOFs derivatives to achieve efficient EMW absorption.The porous carbon-wrapped TiO2/ZrTiO4 composites derived from PCN-415(TiZr-MOFs)are qualified with a minimum reflection loss of−67.8 dB(2.16 mm,13.0 GHz),and a maximum effective absorption bandwidth of 5.9 GHz(2.70 mm).Through in-depth discussions,the synergy of enhanced interfacial polarization and other attenuation mechanisms in the composites is revealed.Therefore,this work confirms the huge potentials of nonmagnetic bimetallic MOFs derivatives in EMW absorption applications.展开更多
Novel TiO2/BiVO4 microfiber heterojunctions were constructed using cotton as biomorphic templates. The as-synthesized samples were characterized by scanning electron microscope, X-ray diffraction, X-ray photoelectron ...Novel TiO2/BiVO4 microfiber heterojunctions were constructed using cotton as biomorphic templates. The as-synthesized samples were characterized by scanning electron microscope, X-ray diffraction, X-ray photoelectron spectroscopy, UV-Vis diffuse reflectance spectra and photocatalytic experiment. The morphology of the as-synthesized TiO2/BiVO4 composites was consisted of a large quantity of microfiber structures with diameter from 2.5 gm to 5 μm, and the surface of samples became more coarse and compact with the increase of weight ratio of TiO2. The TiO2/BiVO4 samples with proper content (10.00wt%) showed the highest pho- tocatalytic degradation activity for methylene blue (MB) degradation among all the samples under visible light, and 88.58%MB could be degraded within 150 min. The enhancement of photocatalytic activity was mainly attributed to the formation of n-n heterojunction at the contact interface of TiO2 and BiVO4, which not only narrowed the band gap of BiVO4 for extending the absorption range of visible light, but also promoted the transfer of charge carriers across interface. A possible photodegradation mechanism of MB in the presence of TiO2/BiVO4 microfibrous photocatalyst was proposed.展开更多
基金Supporting information is available in the online version of this article.
摘要The direct conversion of methane into methanol under mild conditions represents a highly appealing pathway.Regulating the generation of hydroxyl radicals(·OH)is a representative method,but excessive release of·OH will inevitably lead to the over-oxidation of CH3OH.Here,we design AgPd alloy and Co3O4 cascade active sites on the TiO2 surface(AgPd-Co/TiO2)to control the release rate of·OH to improve the selectivity of CH3OH.By incorporating Co3O4 as a hole buffer and storage center,the kinetics of·OH generation at the TiO2 interface can be effectively modulated.This confines the spatial distribution of·OH to the active sites of the AgPd alloy,thus facilitating the directional combination of·CH3 and·OH.The optimal AgPd-Co/TiO2 photocatalyst demonstrates outstanding catalytic performance with the selectivity of CH3OH reaching up to 93%in the liquid phase.AgPd-Co/TiO2 exhibited significantly enhanced selectivity relative to reported TiO2-based photocatalytic systems,while simultaneously achieving comparable methanol yields.This research offers valuable insights for the precise design of composite photocatalysts to achieve highly selective methane oxidation.
摘要Constructing step-scheme(S-scheme)heterojunctions has been confirmed as a promising strategy for enhancing the photocatalytic activity of composite materials.In this work,a series of sulfur-doped g-C3N4(SCN)/TiO2 S-scheme photocatalysts were synthesized using electrospinning and calcination methods.The as-prepared SCN/TiO2 composites showed superior photocatalytic performance than pure TiO2 and SCN in the photocatalytic degradation of Congo Red(CR)aqueous solution.The significant enhancement in photocatalytic activity benefited not only from the 1D well-distributed nanostructure,but also from the S-scheme heterojunction.Furthermore,the XPS analyses and DFT calculations demonstrated that electrons were transferred from SCN to TiO2 across the interface of the SCN/TiO2 composites.The built-in electric field,band edge bending,and Coulomb interaction synergistically facilitated the recombination of relatively useless electrons and holes in hybrid when the interface was irradiated by simulated solar light.Therefore,the remaining electrons and holes with higher reducibility and oxidizability endowed the composite with supreme redox ability.These results were adequately verified by radical trapping experiments,ESR tests,and in situ XPS analyses,suggesting that the electron immigration in the photocatalyst followed the S-scheme heterojunction mechanism.This work can enrich our knowledge of the design and fabrication of novel S-scheme heterojunction photocatalysts and provide a promising strategy for solving environmental pollution in the future.
基金financially supported by the National Natural Science Foundation of China (No. U1862105)the Natural Science Basic Research Plan in Shaanxi Province of China (Nos. 2017JZ001 and 2018KJXX-008)+2 种基金the Fundamental Research Funds for the Central Universities (No. cxtd2017004)the Science and Technology Project of Henan Province (No. 182106000029)he Key Research and Development Program of Shaanxi Province (No. 2018ZDCXL-SF-02-04)
摘要In this work,we designed and prepared the novel TiO2@ZnIn2 S4 nano-sized hollow structure via templating method assisted by hydrothermal synthesis process.Its unique hollow structure and type-II heterojunction between TiO2 hollow nanospheres and ZnIn2 S4 nanosheet can provide enough interior cavities and transfer paths for the light absorption and charge quick migration.The crystal structure,morphology and charges separation property were measured.The characterization results show that the hollow-structured Ti O2@ZnIn2 S4 was successfully prepared,and the optimal sample exhibited excellent photocatalytic hydrogen generation compared with TiO2/ZnIn2 S4 cluster exceeding by a factor of 1.1 under overall light irradiation.Specially,the detailed mechanism of the photocatalytic H2 evolution and charge carrier migration for the as-prepared TiO2@ZnIn2 S4 hollow nanosphere was also studied.
基金The authors acknowledge funding from the National Natural Science Foundation of China(Nos.51572157,21902085,and 51702188)Natural Science Foundation of Shandong Province(No.ZR2019QF012)+1 种基金Fundamental Research Funds for the Central Universities(No.2018JC036 and No.2018JC046)Young Scholars Program of Shandong University(No.2018WLJH25).
摘要Modern communication technologies put forward higher requirements for electromagnetic wave(EMW)absorption materials.Metal-organic framework(MOF)derivatives have been widely concerned with its diverse advantages.To break the mindset of magneticderivative design,and make up the shortage of monometallic non-magnetic derivatives,we first try non-magnetic bimetallic MOFs derivatives to achieve efficient EMW absorption.The porous carbon-wrapped TiO2/ZrTiO4 composites derived from PCN-415(TiZr-MOFs)are qualified with a minimum reflection loss of−67.8 dB(2.16 mm,13.0 GHz),and a maximum effective absorption bandwidth of 5.9 GHz(2.70 mm).Through in-depth discussions,the synergy of enhanced interfacial polarization and other attenuation mechanisms in the composites is revealed.Therefore,this work confirms the huge potentials of nonmagnetic bimetallic MOFs derivatives in EMW absorption applications.
基金This work was supported by Program Funded by Sha.anxi Department (No.2013JK0690), the Scientific Research Provincial Education Fundamental Research Funds of Xianyang Normal University (No. 14XSYK011, No.12XSYK025), Shaanxi Province Natural Science Foundation (No.2015JQ5188).
摘要Novel TiO2/BiVO4 microfiber heterojunctions were constructed using cotton as biomorphic templates. The as-synthesized samples were characterized by scanning electron microscope, X-ray diffraction, X-ray photoelectron spectroscopy, UV-Vis diffuse reflectance spectra and photocatalytic experiment. The morphology of the as-synthesized TiO2/BiVO4 composites was consisted of a large quantity of microfiber structures with diameter from 2.5 gm to 5 μm, and the surface of samples became more coarse and compact with the increase of weight ratio of TiO2. The TiO2/BiVO4 samples with proper content (10.00wt%) showed the highest pho- tocatalytic degradation activity for methylene blue (MB) degradation among all the samples under visible light, and 88.58%MB could be degraded within 150 min. The enhancement of photocatalytic activity was mainly attributed to the formation of n-n heterojunction at the contact interface of TiO2 and BiVO4, which not only narrowed the band gap of BiVO4 for extending the absorption range of visible light, but also promoted the transfer of charge carriers across interface. A possible photodegradation mechanism of MB in the presence of TiO2/BiVO4 microfibrous photocatalyst was proposed.