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学者姓名：郑坤
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Abstract ：
Photocatalytic two-electron oxygen reduction to produce high-value hydrogen peroxide (H2O2) is gaining popularity as a promising avenue of research. However, structural evolution mechanisms of catalytically active sites in the entire photosynthetic H2O2 system remains unclear and seriously hinders the development of highly-active and stable H2O2 photocatalysts. Herein, we report a high-loading Ni single-atom photocatalyst for efficient H2O2 synthesis in pure water, achieving an apparent quantum yield of 10.9% at 420nm and a solar-to-chemical conversion efficiency of 0.82%. Importantly, using in situ synchrotron X-ray absorption spectroscopy and Raman spectroscopy we directly observe that initial Ni-N-3 sites dynamically transform into high-valent O-1-Ni-N-2 sites after O-2 adsorption and further evolve to form a key *OOH intermediate before finally forming HOO-Ni-N-2. Theoretical calculations and experiments further reveal that the evolution of the active sites structure reduces the formation energy barrier of *OOH and suppresses the O=O bond dissociation, leading to improved H2O2 production activity and selectivity.
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| GB/T 7714 | Zhang, Xu , Su, Hui , Cui, Peixin et al. Developing Ni single-atom sites in carbon nitride for efficient photocatalytic H2O2 production [J]. | NATURE COMMUNICATIONS , 2023 , 14 (1) . |
| MLA | Zhang, Xu et al. "Developing Ni single-atom sites in carbon nitride for efficient photocatalytic H2O2 production" . | NATURE COMMUNICATIONS 14 . 1 (2023) . |
| APA | Zhang, Xu , Su, Hui , Cui, Peixin , Cao, Yongyong , Teng, Zhenyuan , Zhang, Qitao et al. Developing Ni single-atom sites in carbon nitride for efficient photocatalytic H2O2 production . | NATURE COMMUNICATIONS , 2023 , 14 (1) . |
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Abstract ：
Polymeric carbon nitride (C3N4) is a very attractive candidate to produce photocatalytic hydrogen peroxide (H2O2) due to its low-cost, metal-free characteristics. However, the low efficiency would limit its development to higher yields because of insufficient light absorption and electron-hole separation. Here, we developed a simple method to anchor CN quantum dots (QDs) onto g-C3N4 nanosheets to form a homojunction structure (HJ-C3N4), which could improve photocatalytic performance largely without introducing metal elements. Its superior efficiency is a result of the band alignment by the homojunction structure providing excellent electron-hole separation and QDs providing suppressed recombination. Simultaneously, the light responsiveness of QDs endows a wide spectrum-responsive adsorption and enhances the adsorption intensity. The H2O2 yield of the HJ-C3N4 reached 115 mu mol L-1 h(-1) in pure water by visible light, which has an 8.6x higher production than g-C3N4 nanosheets. The material design of 0D/2D homojunction could be extended to other materials with specific band alignment.
Keyword ：
Band alignment Band alignment Carbon nitride Carbon nitride Quantum dots Quantum dots H2O2 H2O2 Homojunction Homojunction
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| GB/T 7714 | Ma, Peijie , Zhang, Xu , Wang, Cong et al. Band alignment of homojunction by anchoring CN quantum dots on g-C3N4 (0D/2D) enhance photocatalytic hydrogen peroxide evolution [J]. | APPLIED CATALYSIS B-ENVIRONMENTAL , 2022 , 300 . |
| MLA | Ma, Peijie et al. "Band alignment of homojunction by anchoring CN quantum dots on g-C3N4 (0D/2D) enhance photocatalytic hydrogen peroxide evolution" . | APPLIED CATALYSIS B-ENVIRONMENTAL 300 (2022) . |
| APA | Ma, Peijie , Zhang, Xu , Wang, Cong , Wang, Zhiwei , Wang, Kaiwen , Feng, Yibo et al. Band alignment of homojunction by anchoring CN quantum dots on g-C3N4 (0D/2D) enhance photocatalytic hydrogen peroxide evolution . | APPLIED CATALYSIS B-ENVIRONMENTAL , 2022 , 300 . |
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Abstract ：
Phase transition is a physical phenomenon that attracts great interest of researchers. Although the theory of second-order phase transitions is well-established, their atomic-scale dynamics in polycrystalline materials remains elusive. In this work, second-order phase transitions in polycrystalline Cu2Se at the transition temperature are directly observed by in situ aberration-corrected transmission electron microscopy. Phase transitions in microcrystalline Cu2Se start at the grain boundaries and extend inside the grains. This phenomenon is more pronounced in nanosized grains. Analysis of phase transitions in nanocrystalline Cu2Se with different grain boundaries demonstrates that grain boundary energy dominates unsynchronized phase transition behavior. This suggests that the energy of grain boundaries is the key factor influencing the energetic barrier for initiation of phase transition. The findings advance atomic-scale understanding of second-order phase transitions, which is crucial for the control of this process in polycrystalline materials.
Keyword ：
Se-2 Se-2 unsynchronized phase transition unsynchronized phase transition atomic-scale atomic-scale in situ transmission electron microscopy in situ transmission electron microscopy Cu Cu
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| GB/T 7714 | Yuan, Hua-Lei , Wang, Kaiwen , Hu, Hanwen et al. Atomic-Scale Observation of Grain Boundary Dominated Unsynchronized Phase Transition in Polycrystalline Cu2Se [J]. | ADVANCED MATERIALS , 2022 , 34 (40) . |
| MLA | Yuan, Hua-Lei et al. "Atomic-Scale Observation of Grain Boundary Dominated Unsynchronized Phase Transition in Polycrystalline Cu2Se" . | ADVANCED MATERIALS 34 . 40 (2022) . |
| APA | Yuan, Hua-Lei , Wang, Kaiwen , Hu, Hanwen , Yang, Lei , Chen, Jie , Zheng, Kun . Atomic-Scale Observation of Grain Boundary Dominated Unsynchronized Phase Transition in Polycrystalline Cu2Se . | ADVANCED MATERIALS , 2022 , 34 (40) . |
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Abstract ：
Defect engineering modified graphite carbon nitride (g-C3N4) has been widely used in various photocatalytic systems due to the enhanced catalytic activity of multiple defect sites (such as vacancies or functional groups). However, the key mechanism of action in each defect site in the corresponding photocatalytic surface reactions is still unclear. Here, the -C N groups and N vacancies were sequentially introduced into g-C3N4 (Nv-C N-CN) for photocatalytic production of high-value and multifunctional H2O2, and the effect of dual defect sites on the overall photocatalytic conversion process was systematically analyzed. The modification of the dual defect sites forms an electron-rich structure and leads to a more localized charge density distribution, which not only enhances the light absorption and carrier separation capabilities, but also significantly improves the selectivity and activity of H2O2 generation. Importantly, detailed experimental characterizations and theoretical calculations clearly revealed the key role of each defect site in the photocataLytic H2O2 surface reaction mechanism: the N vacancies can effectively adsorb and activate O-2, and the -C N groups facilitate the adsorption of H+, which synergistically promote H2O2 generation. The Nv-C N-CN reached a H2O2 generation rate of 3093 mu moL g(-1)h(-1) and achieved an apparent quantum efficiency of 36.2% at 400 nm, significantly surpassing the previously reported g-C3N4-based photocatalysts. Meanwhile, a solar-to-chemical conversion efficiency of 0.23% was achieved in pure water. Constructing defects and understanding their crucial role provides significant insights into the rational use of defect engineering to design and synthesize highly active catalytic materials for energy conversion and environmental remediation.
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| GB/T 7714 | Zhang, Xu , Ma, Peijie , Wang, Cong et al. Unraveling the dual defect sites in graphite carbon nitride for ultra-high photocatalytic H2O2 evolution [J]. | ENERGY & ENVIRONMENTAL SCIENCE , 2022 , 15 (2) : 830-842 . |
| MLA | Zhang, Xu et al. "Unraveling the dual defect sites in graphite carbon nitride for ultra-high photocatalytic H2O2 evolution" . | ENERGY & ENVIRONMENTAL SCIENCE 15 . 2 (2022) : 830-842 . |
| APA | Zhang, Xu , Ma, Peijie , Wang, Cong , Gan, Liyong , Chen, Xianjie , Zhang, Peng et al. Unraveling the dual defect sites in graphite carbon nitride for ultra-high photocatalytic H2O2 evolution . | ENERGY & ENVIRONMENTAL SCIENCE , 2022 , 15 (2) , 830-842 . |
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Abstract ：
The main aspects of material research: material synthesis, material structure, and material properties, are interrelated. Acquiring atomic structure information of electron beam sensitive materials by electron microscope, such as porous zeolites, organic-inorganic hybrid perovskites, metal-organic frameworks, is an important and challenging task. The difficulties in characterization of the structures will inevitably limit the optimization of their synthesis methods and further improve their performance. The emergence of integrated differential phase contrast scanning transmission electron microscopy (iDPC-STEM), a STEM characterization technique capable of obtaining images with high signal-to-noise ratio under lower doses, has made great breakthroughs in the atomic structure characterization of these materials. This article reviews the developments and applications of iDPC-STEM in electron beam sensitive materials, and provides an outlook on its capabilities and development.
Keyword ：
low dose low dose electron microscopic characterization electron microscopic characterization electron beam sensitive materials electron beam sensitive materials iDPC-STEM iDPC-STEM
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| GB/T 7714 | Wang, Hongyi , Liu, Linlin , Wang, Jiaxing et al. The Development of iDPC-STEM and Its Application in Electron Beam Sensitive Materials [J]. | MOLECULES , 2022 , 27 (12) . |
| MLA | Wang, Hongyi et al. "The Development of iDPC-STEM and Its Application in Electron Beam Sensitive Materials" . | MOLECULES 27 . 12 (2022) . |
| APA | Wang, Hongyi , Liu, Linlin , Wang, Jiaxing , Li, Chen , Hou, Jixiang , Zheng, Kun . The Development of iDPC-STEM and Its Application in Electron Beam Sensitive Materials . | MOLECULES , 2022 , 27 (12) . |
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Abstract ：
Te-free Bi2S3-based thermoelectric materials show great potential for eco-friendly and industrial scale-up applications because of their high-abundance, low-cost, low-toxicity, and low-thermal-conductivity features. However, their low figure of merit, ZT limits their further applications. In this work, we report a high ZT of similar to 0.8 at similar to 760 K in n-type polycrystalline Bi2S3 by a combination of hierarchical structure manipulation and carrier density optimization. A step-by-step fabrication by using mechanical alloying, high-pressure and high-temperature treatment, spark plasma sintering, and annealing leads to unique micro/nanostructures in polycrystalline Bi2S3 including refined grains, high-density Bi-rich nanoprecipitates, significant lattice distortions, and nanopores that confirmed by comprehensive characterizations, which contribute to significantly suppressed lattice thermal conductivity of 0.41 W m(-1) K-1 at similar to 760 K. A further 0.5 mol% CuCl2-doping triggers impurity band in the electronic structure of Bi2S3 and narrows the bandgap for optimizing the carrier concentration at similar to 1 x 10(20) cm(-3), confirmed by both experimental results and first-principles density functional theory calculations. The optimized carrier concentration and maintained low lattice thermal conductivity give rise to a high power factor of similar to 5.3 mu W cm(-1) K-2 and high ZT that ranks as a top value. This work provides a new route to achieve high thermoelectric performance in n-type polycrystalline Bi2S3.
Keyword ：
Thermoelectric Thermoelectric Bi2S3 Bi2S3 Calculation Calculation Doping Doping Structure Structure
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| GB/T 7714 | Ji, Wenting , Shi, Xiao-Lei , Liu, Wei-Di et al. Boosting the thermoelectric performance of n-type Bi2S3 by hierarchical structure manipulation and carrier density optimization [J]. | NANO ENERGY , 2021 , 87 . |
| MLA | Ji, Wenting et al. "Boosting the thermoelectric performance of n-type Bi2S3 by hierarchical structure manipulation and carrier density optimization" . | NANO ENERGY 87 (2021) . |
| APA | Ji, Wenting , Shi, Xiao-Lei , Liu, Wei-Di , Yuan, Hualei , Zheng, Kun , Wan, Biao et al. Boosting the thermoelectric performance of n-type Bi2S3 by hierarchical structure manipulation and carrier density optimization . | NANO ENERGY , 2021 , 87 . |
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Abstract ：
In this work, Fe2O3 supported single atom Pt (x Pt1/Fe2O3, x = 0.25 and 0.5 wt%) catalysts (SACs) are synthesized via a novel and simple impregnation-pyrolysis method. HAADF-STEM images show that Pt is atomically dispersed on the surface of Fe2O3. All samples exhibit good light-thermal conversion efficiency, which can increase the surface temperature of catalysts to 210 degrees C. The 0.5 Pt1/Fe2O3 exhibits the best photothermal catalytic performance (the toluene conversion and CO2 yield are 95 % and 87 %, respectively) for toluene oxidation under the irradiation of simulated sunlight with light intensity of 720 mW/cm2, which is attributed to its good lightthermal conversion efficiency and low temperature reducibility. The Vis-IR light plays a critical role in the photothermal catalytic oxidation of toluene in the whole solar spectrum. Furthermore, the possible photothermal catalytic reaction pathway of toluene oxidation is proposed based on the TD-GC/MS and in-situ DRIFTS experiments.
Keyword ：
Light-driven photothermal catalysis Light-driven photothermal catalysis Catalytic oxidation mechanism Catalytic oxidation mechanism Single atom Pt catalyst Single atom Pt catalyst Volatile organic compounds Volatile organic compounds Toluene oxidation Toluene oxidation
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| GB/T 7714 | Wang, Zhiwei , Xie, Shaohua , Feng, Ying et al. Simulated solar light driven photothermal catalytic purification of toluene over iron oxide supported single atom Pt catalyst [J]. | APPLIED CATALYSIS B-ENVIRONMENTAL , 2021 , 298 . |
| MLA | Wang, Zhiwei et al. "Simulated solar light driven photothermal catalytic purification of toluene over iron oxide supported single atom Pt catalyst" . | APPLIED CATALYSIS B-ENVIRONMENTAL 298 (2021) . |
| APA | Wang, Zhiwei , Xie, Shaohua , Feng, Ying , Ma, Peijie , Zheng, Kun , Duan, Erhong et al. Simulated solar light driven photothermal catalytic purification of toluene over iron oxide supported single atom Pt catalyst . | APPLIED CATALYSIS B-ENVIRONMENTAL , 2021 , 298 . |
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Abstract ：
A high-efficiency of 25.9% for perovskite/Si heterojunction tandem solar cells is achieved with an open-circuit voltage of 1.74 V contributed by approximate to 1.02 and approximate to 0.72 V from the top and bottom cells, respectively. The results demonstrate that the addition of methylammonium chloride (MACl) effectively mitigates the open-circuit voltage loss in the perovskite cell, where the MA cation tunes the bandgap while the Cl anion facilitates grain growth with less boundaries. Meanwhile, the excess lead iodide (PbI2) caused by the evaporation of MACl plays a beneficial passivation role to achieve high open-circuit voltage. The performance of the tandem solar cells is a synergic consequence of all cations and anions considering the thickness, bandgap, phase stability, and defect in the perovskite absorber.
Keyword ：
high efficiency high efficiency Si tandem solar cells Si tandem solar cells synergic effect synergic effect open-circuit voltage loss open-circuit voltage loss cations and anions cations and anions perovskite perovskite
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| GB/T 7714 | He, Yongcai , Tang, Zeguo , Mao, Lin et al. Minimizing Open-Circuit Voltage Loss in Perovskite/Si Tandem Solar Cells via Exploring the Synergic Effect of Cations and Anions [J]. | PHYSICA STATUS SOLIDI-RAPID RESEARCH LETTERS , 2021 . |
| MLA | He, Yongcai et al. "Minimizing Open-Circuit Voltage Loss in Perovskite/Si Tandem Solar Cells via Exploring the Synergic Effect of Cations and Anions" . | PHYSICA STATUS SOLIDI-RAPID RESEARCH LETTERS (2021) . |
| APA | He, Yongcai , Tang, Zeguo , Mao, Lin , Yang, Shaofei , Yang, Tian , Xie, Minghui et al. Minimizing Open-Circuit Voltage Loss in Perovskite/Si Tandem Solar Cells via Exploring the Synergic Effect of Cations and Anions . | PHYSICA STATUS SOLIDI-RAPID RESEARCH LETTERS , 2021 . |
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Abstract ：
Discovering high-performance near-room-temperature thermoelectric materials is extremely imperative to widen the practical application in thermoelectric power generation and refrigeration. Here, ternary Ag2Se1-xTex (x = 0.1, 0.2, 0.3, 0.4, and 0.5) materials are prepared via the wet-mechanical alloying and spark plasma sintering process to investigate their near-room-temperature thermoelectric properties. From density functional theory calculation and single-parabolic-band modeling study, we found that the reduced contribution of Se 4p orbitals to the total density of states decreases the carrier effective mass with increasing Te content, which should enhance the theoretically maximum zT. These calculation results are also verified by the experimental results. Meanwhile, complex microstructures including dislocations, nanograins, high-density boundaries, Te-Se substitution, lattice distortions, and localized strain have been observed in ternary Ag2Se1-xTex. These complex microstructures strengthen phonon scattering and in turn lead to ultralow lattice thermal conductivity in the range of 0.21-0.31 W m(-1) K-1 in ternary Ag2Se1-xTex at 300 K. Although the increased deformation potential suppresses the carrier mobility, benefiting from the engineered band structures and ultralow lattice thermal conductivity, a high zT of >1 can be potentially obtained in the ternary Ag2Se1-xTex with appropriate carrier concentration. This study indicates that ternary Ag2Se1-xTex is a promising candidate for near-room-temperature thermoelectric applications.
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| GB/T 7714 | Chen, Jie , Yuan, Hualei , Zhu, Yu-Ke et al. Ternary Ag2Se1-xTex: A Near-Room-Temperature Thermoelectric Material with a Potentially High Figure of Merit [J]. | INORGANIC CHEMISTRY , 2021 , 60 (18) : 14165-14173 . |
| MLA | Chen, Jie et al. "Ternary Ag2Se1-xTex: A Near-Room-Temperature Thermoelectric Material with a Potentially High Figure of Merit" . | INORGANIC CHEMISTRY 60 . 18 (2021) : 14165-14173 . |
| APA | Chen, Jie , Yuan, Hualei , Zhu, Yu-Ke , Zheng, Kun , Ge, Zhen-Hua , Tang, Jun et al. Ternary Ag2Se1-xTex: A Near-Room-Temperature Thermoelectric Material with a Potentially High Figure of Merit . | INORGANIC CHEMISTRY , 2021 , 60 (18) , 14165-14173 . |
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Abstract ：
一种去除扫描电镜中非导电样品荷电效应的方法涉及扫描电镜领域。为了在不镀膜的条件下看到绝缘样品的真实形貌而又不会产生荷电效应，本专利提出一种消除扫描电镜下观察非导电样品的方法并提出扫描电镜下观察非导电样品的装置。利用该方法可以有效的消除部分样品表面的荷电效应，达到清晰成像的目的。本发明不但省去了复杂的镀膜工艺而且可以在扫描电镜下清楚地反映出绝缘样品形貌。
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| GB/T 7714 | 刘陵恩 , 张跃飞 , 唐亮 et al. 一种去除扫描电镜中非导电样品荷电效应的方法 : CN202111214492.0[P]. | 2021-10-19 . |
| MLA | 刘陵恩 et al. "一种去除扫描电镜中非导电样品荷电效应的方法" : CN202111214492.0. | 2021-10-19 . |
| APA | 刘陵恩 , 张跃飞 , 唐亮 , 张宜旭 , 郑坤 , 王永峰 et al. 一种去除扫描电镜中非导电样品荷电效应的方法 : CN202111214492.0. | 2021-10-19 . |
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