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Sodium-doped carbon nitride nanotubes for efficient visible light-driven hydrogen production

Nano Research 2018年第4期11卷 2295-2309页

作者： Longshuai Zhang Ning Ding Muneaki Hashimoto Koudai Iwasaki Noriyasu Chikamori Kazuya Nakata Yuzhuan Xu Jiangjian Shi Huijue Wu Yanhong Luo Dongmei Li Akira Fujishima Qingbo Meng Key Laboratory for Renewable Energy Chinese Academy of Sciences (CAS) Beijing Key Laboratory for New Energy Materials and Devices Beijing National Laboratory for Condensed Matter Physics Institute of Physics CAS Beijing 100190 China Photocatalysis International Research Center Research Institute for Science and Technology Tokyo University of Science 2641 Yamazaki Noda Chiba 278-0022 Japan School of Physical Sciences University of Chinese Academy of Sciences Beijing 100049 China

Sodium-doped carbon nitride nanotubes （Nax-CNNTs） were prepared by a green and simple two-step method and applied in photocatalytic water splitting for the first time. Transmission electron microscopy （TEM） element mapping and X-ray photoelectron spectroscopy （XPS） measurements confirm that sodium was successfully introduced in the carbon nitride nanotubes （CNNTs）, and the intrinsic structure of graphitic carbon nitride （g-C3N4） was also maintained in the products. Moreover, the porous structure of the CNNTs leads to relatively large specific surface areas. Photocatalytic tests indicate that the porous tubular structure and Na＋ doping can synergistically enhance the hydrogen evolution rate under visible light （λ 〉 420 nm） irradiation in the presence of sacrificial agents, leading to a hydrogen evolution rate as high as 143 μmol·h-1 （20 mg catalyst）. Moreover, other alkali metal-doped CNNTs, such as Lix-CNNTs and Kx-CNNTs, were tested; both materials were found to enhance the hydrogen evolution rate, but to a lower extent compared with the Nax-CNNTs. This highlights the general applicability of the present method to prepare alkali metal-doped CNNTs; a preliminary mechanism for the photocatalytic hydrogen evolution reaction in the Nax-CNNTs is also proposed.

关键词： graphitic carbon nitrides nanotubes alkali metal doping photocatalytic hydrogen production hydrothermal/thermopolymerization processes two-step synthesis

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Ethane dehydrogenation over the g-C_(3)N_(4)supported metal singleatom catalysts to enhance reactivity and coking-resistance ability

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Nano Research 2023年第5期16卷 6142-6152页

作者： Yuan Zhang Baojun Wang Maohong Fan Lixia Ling Riguang Zhang College of Chemical Engineering and Technology Taiyuan University of TechnologyTaiyuan 030024China State Key Laboratory of Clean and Efficient Coal Utilization Taiyuan University of TechnologyTaiyuan 030024China Departments of Chemical and Petroleum Engineering University of WyomingLaramieWY 82071USA School of Civil and Environmental Engineering Georgia Institute of TechnologyAtlantaGA 30332USA School of Energy Resources University of WyomingLaramieWY 82071USA

Ethane dehydrogenation(EDH)to produce ethylene requires high operating temperature to achieve satisfactory ethylene yield,however,this process leads to coke formation and catalyst ***,an active site isolation strategy was employed to inhibit side reaction and coke formation over fifteen types of metal single-atom metal/graphitic carbon nitride(M/g-C_(3)N_(4))*** functional theory(DFT)calculations completely describe reaction network of ethane *** kinetic Monte Carlo simulations were carried out to evaluate catalytic performance under the realistic *** Co/g-C_(3)N_(4),Rh/g-C_(3)N_(4),Ni/g-C_(3)N_(4)catalysts were screened out to exhibit higher C_(2)H_(4)(g)formation activity and C_(2)H_(4)(g)selectivity close to or equal to 100%.The low reactant partial pressure 0%–5%at atmospheric pressure facilitates ethane dehydrogenation,and the appropriate temperatures over Co/g-C_(3)N_(4),Rh/g-C_(3)N_(4),Ni/g-C_(3)N_(4)catalysts are 673.15,723.15,723.15 K,***,Co/g-C_(3)N_(4)catalyst presents the highest C_(2)H_(4)(g)formation activity,attributing to the appropriate antibonding strength between C atom and metal ***,a simple descriptor,the reaction energy of C_(2)H_(5)*dehydrogenation to C_(2)H_(4)*,was proposed to quantitatively and quickly evaluate C_(2)H_(4)(g)formation *** present study laid a solid foundation for efficient design and development of single-atom catalysts with high-performance for selective dehydrogenation of alkanes.

关键词： ethane dehydrogenation single-atom catalyst graphitic carbon nitrides density functional theory(DFT)calculations kinetic Monte Carlo

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Reduced-sized monolayer carbon nitride nanosheets for highly improved photoresponse for cell imaging and photocatalysis

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Science China Materials 2017年第2期60卷 109-118页

作者：梁庆华李智白宇黄正宏康飞宇杨全红 Shenzhen Key Laboratory for Graphene-based Materials Graduate School at Shenzhen Tsinghua University Shenzhen 518055 China Technical Institute of Physics and Chemistry Chinese Academy of Sciences (CAS) Beijing 100190 China Key Laboratory of Advanced Materials (Ministry of Education) School of Materials Science and Engineering Tsinghua University Beijing 100084 China School of Chemical Engineering and Technology Tianjin University Tianjin 300072 China

Two-dimensional graphitic carbon nitride（g-C_3N_4） nanosheets（GCNNs） have been considered as an attractive metal-free semiconductor because of their superior catalytic,optical,and electronic ***,it is still challenging to prepare monolayer GCNNs with a reduced lateral size in ***,a highly efficient ultrasonic technique was used to prepare nanosized monolayer graphitic carbon nitride nanosheets（NMGCNs） with a thickness of around 0.6 nm and an average lateral size of about 55 *** a reduced lateral size yet monolayer thickness,NMGCNs show unique photo-responsive properties as compared to both large-sized GCNNs and GCN quantum dots.A dispersion of NMGCNs in water has good stability and exhibits strong blue fluorescence with a high quantum yield of 32%,showing good biocompatibility for cell ***,compared to the multilayer GCNNs,NMGCNs show a highly improved photocatalysis under visible light ***,NMGCNs,characterized with monolayer and nanosized lateral dimension,fill the gap between large size（very high aspect ratio） and quantum dot-like counterparts,and show great potential applications as sensors,photo-related and electronic devices.

关键词： graphitic carbon nitrides monolayer nanosheets photocatalysis fluorescence cell imaging

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