Modifying the chemical surrounding of N-doped carbon supported single-atom catalysts(SA/NCs)through heteroatom doping is a mainstream approach to optimize their performance for electrocatalytic CO2 reduction reacti...Modifying the chemical surrounding of N-doped carbon supported single-atom catalysts(SA/NCs)through heteroatom doping is a mainstream approach to optimize their performance for electrocatalytic CO2 reduction reaction.However,conventional SA/NCs mainly consists of in-plane metal sites feature with tightly symmetrical M–N4 coordination environments,limiting the regulatory strength of heteroatom doping.Herein,we proposed an edge-assisted heteroatom doping regulation strategy by constructing edge-type Ni sites supported on a hollow and leaf-shaped P-doped NC substrate(eNi/H-NPC).The two-dimensional leaf-shaped and hollow carbon can expose enriched edges.The edge structure can promote the accessibility of active sites,more importantly,intensifies electronic perturbation induced by heteroatom doping.Resultantly,the charge symmetry distribution of Ni–N_4 site is significantly disrupted,and energy barrier associated with the formation of*COOH intermediate is further diminished.eNi/HNPC achieves CO faradaic efficiency(FECO)near 100%at-0.6 V versus reversible hydrogen electrode(vs.RHE)and maintains FECOover 90%from-0.6 to-1.1 V(vs.RHE)in H-type cells.Remarkably,in gas-diffusion flow cells,eNi/H-NPC exhibits FECOreaches 98.9%and 96.5%in neutral and acidic electrolytes with the CO current density reach 283.5,and 397.2 mA cm-2,respectively,which are much superior than that of the bulk material with dominant in-plane active sites.Moreover,eNi/H-NPC serves as an efficient cathode in Zn–CO2 batteries,realized a discharge power density of 4.1 mW cm-2,and exceptional cycling durability over 35 h.展开更多
In view of the dearth of active components and the unsatisfactory dispersion of Cu-based catalysts,it is imperative to undertake a detailed investigation of catalysts with enhanced catalytic performance.In order to ac...In view of the dearth of active components and the unsatisfactory dispersion of Cu-based catalysts,it is imperative to undertake a detailed investigation of catalysts with enhanced catalytic performance.In order to achieve a balance between the catalytic activity and stability in the reaction process,a series of P-atom doped Cu0/Cuδ+binary Cu-based catalysts were prepared by means of heteroatom introduction and heat treatment.The introduction of P enhanced the stability of Cu during heat treatment,thereby inhibiting the excessive agglomeration of Cu.The structure of the Cu0/Cuδ+binary catalyst was modified through heat treatment and HCl activation,and the relationship between its structure and catalytic activity was subsequently investigated.The activation process of HCl facilitated the conversion of the Cu0state to the Cu-Cl state and augmented the valence state of Cu.The valence modulation of the Cu site by HCl during the reaction prevented the over-reduction of the Cu site by acetylene and enhanced the stability of the catalyst.The 3Cu/5Cu P/AC-800 catalyst was operated for 50 h without significant deactivation under the reaction conditions of T=180°C,V(HCl)/V(C2H2)=1.15 and GHSV(C2H2)=180 h-1.This design strategy provides a novel reference point for further studies of Cu Cl2based catalysts for acetylene hydrochlorination.展开更多
文章通过两步反应合成共轭超交联聚合物(TPP-CHCP)。TPP-CHCP有较宽的光吸收区间(400~900 nm),可作为光致原子转移自由基聚合(photocatalyzed atom transfer radical polymerization,P-ATRP)的光催化剂。TPP-CHCP可在940 nm近红外光照射...文章通过两步反应合成共轭超交联聚合物(TPP-CHCP)。TPP-CHCP有较宽的光吸收区间(400~900 nm),可作为光致原子转移自由基聚合(photocatalyzed atom transfer radical polymerization,P-ATRP)的光催化剂。TPP-CHCP可在940 nm近红外光照射下,驱动丙烯酸甲酯(MA)和甲基丙烯酸甲酯(MMA)的P-ATRP反应且单体转化率达到99%。所得聚合物的结构明确,分子量可控,分子量分布(D-s<1.18)窄。在太阳光照射条件下,TPP-CHCP依然具有优异的光催化活性,可高效制备嵌段共聚物。展开更多
Abstract In this study, a kind of fluorinated copolyfluorene, named poly[(4-(octyloxy)-9,9-diphenylfluorene-2,7-diyl)-alt- (2,3,5,6-tetrafluoro-1,4-phenylene)] (PODPF-TFP), is synthesized by facile palladium-b...Abstract In this study, a kind of fluorinated copolyfluorene, named poly[(4-(octyloxy)-9,9-diphenylfluorene-2,7-diyl)-alt- (2,3,5,6-tetrafluoro-1,4-phenylene)] (PODPF-TFP), is synthesized by facile palladium-based direct aromatization. Compared to the non-fluorinated counterpart, poly[(4-(octyloxy)-9,9-diphenylfluorene-2,7-diyl)-alt-(p-phenylene)] (PODPF-P), deeper HOMO/LUMO energy level combined with steric hindrance effect endow PODPF-TFP with excellent spectra and morphology stability. Finally, organic field-effect transistor (OFET) memory devices are fabricated with PODPF-P/PODPF- TFP as the dielectric layers, and they both exhibit flash type storage characteristic. Owing to the electronegativity of fluorine atom, the device based on PODPF-TFP exhibits larger memory window and more stable Ion/Ioff ratio during a retention time of 10^4 s as well as a better aging stability. The present study suggests that fluorinated p-n copolyfluorene electrets could enhance the capabilities of charge trapping and storage, which are promising for OFET memory devices.展开更多
Thin films of perovskite manganese oxide Lao.66Ca0.29K0.05MnO3(LCKMO) on Au/ITO(ITO=indium tin oxide) substrates were prepared by off-axis radio frequency magnetron sputtering and characterized by X-ray diffrac- t...Thin films of perovskite manganese oxide Lao.66Ca0.29K0.05MnO3(LCKMO) on Au/ITO(ITO=indium tin oxide) substrates were prepared by off-axis radio frequency magnetron sputtering and characterized by X-ray diffrac- tion(XRD), high-resolution transmission electron microscopy(HRTEM), and conductive atomic force microscopy (C-AFM) at room temperature. The thin films with thickness ranged from 100 nm to 300 nm basically show cubic structures with a=0.3886 nm, the same as that of the raw material used, but the structures are highly modulated. C-AFM results revealed that the atomic scale p-n junction feature of the thin films was the same as that of the single crystals. The preparation of the thin films thus further confirms the possibility of their application extending from micrometer-sized single crystals to macroscopic thin film.展开更多
In this work, we study the influence of carrier gas H2flow rate on the quality of p-type GaN grown and annealed at lower temperatures. It is found that the concentration of H atoms in Mg-doped GaN epilayer can effecti...In this work, we study the influence of carrier gas H2flow rate on the quality of p-type GaN grown and annealed at lower temperatures. It is found that the concentration of H atoms in Mg-doped GaN epilayer can effectively decrease with appropriately reducing the carrier gas H2flow rate, and a high-quality p-type GaN layer could be obtained at a comparatively low annealing temperature by reducing the carrier gas H2flow rate. Meanwhile, it is found that the intensity and wavelength of DAP peak are changed as the annealing temperature varies, which shows that the thermal annealing has a remarkable effect not only on the activation of acceptors but also on the compensation donors.展开更多
基金supported by Basic and Applied Basic Research Foundation of Guangdong province(2024A1515110016 and2023A1515140020)National Natural Science Foundation of China(52070042,and 52300127)。
摘要Modifying the chemical surrounding of N-doped carbon supported single-atom catalysts(SA/NCs)through heteroatom doping is a mainstream approach to optimize their performance for electrocatalytic CO2 reduction reaction.However,conventional SA/NCs mainly consists of in-plane metal sites feature with tightly symmetrical M–N4 coordination environments,limiting the regulatory strength of heteroatom doping.Herein,we proposed an edge-assisted heteroatom doping regulation strategy by constructing edge-type Ni sites supported on a hollow and leaf-shaped P-doped NC substrate(eNi/H-NPC).The two-dimensional leaf-shaped and hollow carbon can expose enriched edges.The edge structure can promote the accessibility of active sites,more importantly,intensifies electronic perturbation induced by heteroatom doping.Resultantly,the charge symmetry distribution of Ni–N_4 site is significantly disrupted,and energy barrier associated with the formation of*COOH intermediate is further diminished.eNi/HNPC achieves CO faradaic efficiency(FECO)near 100%at-0.6 V versus reversible hydrogen electrode(vs.RHE)and maintains FECOover 90%from-0.6 to-1.1 V(vs.RHE)in H-type cells.Remarkably,in gas-diffusion flow cells,eNi/H-NPC exhibits FECOreaches 98.9%and 96.5%in neutral and acidic electrolytes with the CO current density reach 283.5,and 397.2 mA cm-2,respectively,which are much superior than that of the bulk material with dominant in-plane active sites.Moreover,eNi/H-NPC serves as an efficient cathode in Zn–CO2 batteries,realized a discharge power density of 4.1 mW cm-2,and exceptional cycling durability over 35 h.
基金supported by the National Natural Science Foundation of China(No.22062021)the Science and Technology Project of Xinjiang supported by Central Government(No.2022BC001)+3 种基金Science and Technology Planning Project(No.2024AB048)Tianshan Talents Training Program of Xinjiang(Science and Technology Innovation Team,No.CZ002701)the Start-Up Foundation for high-level professionals of Shihezi University(No.RCZK201932)2024 Talent Development Fund-Tianchi Young Doctor of Excellence(No.CZ002744)。
摘要In view of the dearth of active components and the unsatisfactory dispersion of Cu-based catalysts,it is imperative to undertake a detailed investigation of catalysts with enhanced catalytic performance.In order to achieve a balance between the catalytic activity and stability in the reaction process,a series of P-atom doped Cu0/Cuδ+binary Cu-based catalysts were prepared by means of heteroatom introduction and heat treatment.The introduction of P enhanced the stability of Cu during heat treatment,thereby inhibiting the excessive agglomeration of Cu.The structure of the Cu0/Cuδ+binary catalyst was modified through heat treatment and HCl activation,and the relationship between its structure and catalytic activity was subsequently investigated.The activation process of HCl facilitated the conversion of the Cu0state to the Cu-Cl state and augmented the valence state of Cu.The valence modulation of the Cu site by HCl during the reaction prevented the over-reduction of the Cu site by acetylene and enhanced the stability of the catalyst.The 3Cu/5Cu P/AC-800 catalyst was operated for 50 h without significant deactivation under the reaction conditions of T=180°C,V(HCl)/V(C2H2)=1.15 and GHSV(C2H2)=180 h-1.This design strategy provides a novel reference point for further studies of Cu Cl2based catalysts for acetylene hydrochlorination.
摘要文章通过两步反应合成共轭超交联聚合物(TPP-CHCP)。TPP-CHCP有较宽的光吸收区间(400~900 nm),可作为光致原子转移自由基聚合(photocatalyzed atom transfer radical polymerization,P-ATRP)的光催化剂。TPP-CHCP可在940 nm近红外光照射下,驱动丙烯酸甲酯(MA)和甲基丙烯酸甲酯(MMA)的P-ATRP反应且单体转化率达到99%。所得聚合物的结构明确,分子量可控,分子量分布(D-s<1.18)窄。在太阳光照射条件下,TPP-CHCP依然具有优异的光催化活性,可高效制备嵌段共聚物。
基金financially supported by the National Natural Science Funds for Excellent Young Scholar (No.21322402)the National Natural Science Foundation of China (Nos.21274064, 61475074, 21504041 and 61136003)+4 种基金University of Jiangsu Province Natural Science Foundation Project (No.14KJB510027)Natural Science Foundation of Jiangsu Province (No.BM2012010)Synergetic Innovation Center for Organic Electronics and Information DisplaysNatural Science of the Education Committee of Jiangsu Province (No.15KJB430019)Jiangsu Planned Projects for Postdoctoral Research Funds (No.1501019B)
摘要Abstract In this study, a kind of fluorinated copolyfluorene, named poly[(4-(octyloxy)-9,9-diphenylfluorene-2,7-diyl)-alt- (2,3,5,6-tetrafluoro-1,4-phenylene)] (PODPF-TFP), is synthesized by facile palladium-based direct aromatization. Compared to the non-fluorinated counterpart, poly[(4-(octyloxy)-9,9-diphenylfluorene-2,7-diyl)-alt-(p-phenylene)] (PODPF-P), deeper HOMO/LUMO energy level combined with steric hindrance effect endow PODPF-TFP with excellent spectra and morphology stability. Finally, organic field-effect transistor (OFET) memory devices are fabricated with PODPF-P/PODPF- TFP as the dielectric layers, and they both exhibit flash type storage characteristic. Owing to the electronegativity of fluorine atom, the device based on PODPF-TFP exhibits larger memory window and more stable Ion/Ioff ratio during a retention time of 10^4 s as well as a better aging stability. The present study suggests that fluorinated p-n copolyfluorene electrets could enhance the capabilities of charge trapping and storage, which are promising for OFET memory devices.
基金Supported by the National Natural Science Foundation of China(No.90922034)
摘要Thin films of perovskite manganese oxide Lao.66Ca0.29K0.05MnO3(LCKMO) on Au/ITO(ITO=indium tin oxide) substrates were prepared by off-axis radio frequency magnetron sputtering and characterized by X-ray diffrac- tion(XRD), high-resolution transmission electron microscopy(HRTEM), and conductive atomic force microscopy (C-AFM) at room temperature. The thin films with thickness ranged from 100 nm to 300 nm basically show cubic structures with a=0.3886 nm, the same as that of the raw material used, but the structures are highly modulated. C-AFM results revealed that the atomic scale p-n junction feature of the thin films was the same as that of the single crystals. The preparation of the thin films thus further confirms the possibility of their application extending from micrometer-sized single crystals to macroscopic thin film.
基金Project supported by the the Science Challenge Project of China(Grant No.TZ2016003)the National Natural Science Foundation of China(Grant Nos.61674138,61674139,61604145,61574135,61574134,61474142,and 61474110)Beijing Municipal Science and Technology Project(Grant No.Z161100002116037)
摘要In this work, we study the influence of carrier gas H2flow rate on the quality of p-type GaN grown and annealed at lower temperatures. It is found that the concentration of H atoms in Mg-doped GaN epilayer can effectively decrease with appropriately reducing the carrier gas H2flow rate, and a high-quality p-type GaN layer could be obtained at a comparatively low annealing temperature by reducing the carrier gas H2flow rate. Meanwhile, it is found that the intensity and wavelength of DAP peak are changed as the annealing temperature varies, which shows that the thermal annealing has a remarkable effect not only on the activation of acceptors but also on the compensation donors.