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Atomic Nickel on Graphitic Carbon Nitride as a Visible Light-Driven Hydrogen Production Photocatalyst Studied by X-ray Spectromicroscopy

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ACS Sustainable Chemistry and engineering 2023年第14期11卷 5390-5399页

作者： Huang, Yu-Cheng Li, Yanrui Arul, K. Thanigai Ohigashi, Takuji Nga, Ta Thi Thuy Lu, Ying-Rui Chen, Chi-Liang Chen, Jeng-Lung Shen, Shaohua Pong, Way-Faung Dong, Chung-Li Chou, Wu-Ching Department of Electrophysics National Yang Ming Chiao Tung University Hsinchu30010 Taiwan Research Center for X-ray Science & Department of Physics Tamkang University New Taipei City25137 Taiwan International Research Center for Renewable Energy State Key laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Shaanxi Xi’an710049 China Photon Factory Institute of Materials Structure Science High Energy Accelerator Research Organization Tsukabu305-0801 Japan UVSOR Synchrotron Facility Institute for Molecular Science Okazaki444-8585 Japan National Synchrotron Radiation Research Center Hsinchu30010 Taiwan

The photocatalytic production of solar hydrogen through water splitting by graphitic carbon nitride (g-C3N4) has gained substantial interest due to its advantageous characteristics, such as eco-friendliness, wealth on the earth, favorable bandgap, and easy preparation. Nevertheless, the performance for photocatalytic overall water splitting has been significantly restricted owing to the rapid recombination of charge carriers and slow catalytic kinetics. This investigation demonstrates the utilization of a single-atom Ni-terminating agent to coordinate with the heptazine moieties of g-C3N4, resulting in the formation of a new electronic orbital. g-C3N4 with single-atom Ni-termination can achieve highly efficient photocatalytic overall water splitting into H2 and H2O2 upon visible light irradiation, without requiring the use of any additional cocatalysts. The underlying cause of the enhanced photocatalytic performance of single-atom Ni-incorporated g-C3N4 in hydrogen evolution reaction is identified using synchrotron X-ray spectroscopy and microscopy. The X-ray spectro-microscopic results discover that the new hybrid orbital that is critical for optimizing photocatalysis is associated with carbon defects. The atomic and electronic structures and the band gap of g-C3N4 are adjusted by the new hybrid orbital. Moreover, it synergistically enhances visible light absorption, thereby promoting the separation and transfer of photogenerated charge carriers. The single-atom Ni and the adjacent C atom are recognized as the active sites for water oxidation and reduction, respectively, supporting the efficient photocatalytic splitting of water via a two-electron transfer pathway. This study demonstrated a promising material design for promoting photocatalytic activity in solar energy conversion applications. © 2023 American Chemical Society

关键词： Electronic structure

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Pattern and Dynamics of Methane/Water Two-Phase flow in Deep-Shale Illite Nanoslits

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SSRN 2024年

作者： Wang, Rui Yang, Xu Li, Gao Zheng, Wenxiu Zou, Zhenhai Sun, Chengzhen State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Shaanxi Xi’an710049 China State Key Laboratory of Oil and Gas Reservoir Geology and Exploration Southwest Petroleum University Sichuan Chengdu610500 China Air and Missile Defense College Air Force Engineering University Shaanxi Xi’an710051 China Wuhan Second Ship Design and Research Institute Wuhan430202 China

Developing deep shale gas is crucial for the sustainable development of unconventional energy sources. Deep shale has a high illite content, and understanding the structure and flow behaviors of methane and water coexisting in deep shale illite nanoslits is essential for methane transport and production in deep shale reservoirs. Here, molecular dynamics simulations were performed to investigate the methane and water flow characteristics in slit-shaped illite nanopores. The effects of water saturation, acceleration, and pore size on two-phase flow are elucidated. The results show that water molecules preferentially adsorb on the surface of the illite channel. As the water saturation increases, the water phase gradually forms a water film, water bridge, and water lock, ultimately creating methane nanobubbles surrounded by the water phase. The existence of the water phase compresses the methane flow space. With increasing water saturation, the peak methane density near the channel wall gradually disappears, and the density distribution curves show parabolic shapes. The methane flow flux decreases with the increase of water saturation, mainly when the water saturation increases from 0% to 40%. In illite slits with pore sizes ranging from 2 to 4 nm, the flow rates of water and methane increase with increased pore size. These results are expected to provide insights into developing deep shale gas reservoirs, such as optimizing hydraulic fracturing design and reliably predicting production performance. © 2024, The Authors. All rights reserved.

关键词： Methane

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Fabrication of highly reliable joint based on Cu/Ni/Sn double-layer powder for high temperature application

Fabrication of highly reliable joint based on Cu/Ni/Sn doubl...

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作者： Xu, Hongyan Shen, Yaochun Hu, Yihua Li, Jianqiang Xu, Ju Beijing Engineering Laboratory of Electrical Drive System and Power Electronic Device Packaging Technology Micro-Nano Fabrication Technology Department Institute of Electronic Engineering Chinese Academy of Sciences Beijing100190 China University of Chinese Academy of Sciences Beijing100049 China School of Electrical Engineering Electronics and Computer Science University of Liverpool Brownlow Hill LiverpoolL69 3GJ United Kingdom State Key Laboratory of Multiphase Complex System Institute of Process Engineering Chinese Academy of Sciences Beijing100190 China

A highly reliable three-dimensional network structure joint was fabricated based on Cu/Ni/Sn powder with double-layer coatings and transient liquid phase bonding (TLPB) technology for high temperature application. The Cu/Ni/Sn joint is characterized by Cu metal particles embedded in the matrix of (Cu,Ni)6Sn5/Ni3Sn4 intermetallic compounds (IMCs), with a low void ratio, and can be reflowed at low temperatures (6Sn5/ Ni3Sn4 IMCs, and the Cu/Ni/Sn joint had a lower void ratio and a higher shear strength than those of Cu/Sn. The mechanism of the Ni-coating layer inhibiting phase transformation was studied. The high reliable three-dimensional network structure joint based on Cu/Ni/Sn double-layer powder was fabricated for high temperature application. Copyright © International Microelectronics Assembly and Packaging Society

关键词： High temperature applications

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Hydrothermal Hydrolysis Modeling of Lignocellulosic Biomass Using Subcritical Water for Test Packed Bed Reactor

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SSRN 2023年

作者： Wu, Zhonggang Wang, Jiawei Du, Xiaocheng Su, Hanguang China Nuclear Power Operations Co. Ltd. Shenzhen518116 China Department of Mathematics Physics and Electrical Engineering Northumbria University NewcastleNE1 8ST United Kingdom State Key Laboratory of Multiphase Flow in Power Engineering Xian Jiaotong University Xi'An China School of Information Science and Engineering Northeastern University Shenyang China

In this paper, the subcritical water hydrothermal conversion process of lignocellulosic biomass as porous media in packed bed reactor was investigated by numerical simulation. The computational fluid dynamics mathematical modeling was used to describe the transient multi-physical fields formed during the instantaneous formation process of organic functional groups on the bases of experiment. The effect of inlet hydrothermal fluid velocity and temperature on the transient seepage flow, heat and transfer, and organic conversion reaction were investigated by ANSYS FLUENT® software. The results of the simulation indicate that the osmotic pressure and velocity increase with the hydrothermal fluid velocity and temperature. The surface heat transfer coefficient increases with the hydrothermal fluid velocity and temperature, and may reach the maximum within the scope of this paper. Both experimental and numerical simulation results consistently show that within the first 60 minutes of the hydrothermal reaction, the organic reaction rate is mainly determined by the combined model of turbulent-hydrothermal reaction. For a later time period after 60 minutes, the organic reaction rate mainly depends on the single model of hydrothermal reaction. Comparing the same experimental conditions and their real-time measurements, the numerical results in this paper accord with them. © 2023, The Authors. All rights reserved.

关键词： Porous materials

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Unveiling the Unexpected C-C Dissociation Capacity and Intrinsic Mechanism of Undercoordinated Pd Cluster/Ceo2 for the Efficient and Stable Catalytic Mineralization of Propane

SSRN

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SSRN 2022年

作者： Xia, Lianghui Jian, Yanfei Wang, Jingjing Wang, Yao Chai, Shouning Liu, Yujie Li, Lu Yu, Yanke Albilali, Reem He, Chi State Key Laboratory of Multiphase Flow in Power Engineering School of Energy and Power Engineering Xi'an Jiaotong University Shaanxi Xi’an710049 China Department of Chemistry College of Science Imam Abdulrahman Bin Faisal University P.O. Box 1982 Dammam31441 Saudi Arabia National Engineering Laboratory for VOCs Pollution Control Material & Technology University of Chinese Academy of Sciences Beijing101408 China

Light alkanes extensively presented in industrial exhausts have led tremendous harm to the atmospheric environment and human health. However, their stable molecule structure and inferior adsorption and activation efficiency make them as one category of the most intractable pollutants to be efficient controlled. Herein, we developed a Pd single cluster/CeO2 catalyst (Pd/CeO2-SCC-R) by a scalable deposition precipitation strategy, which demonstrates unexpected activity (propane total destructed below 300 oC) and thermal stability (even dramatically treated at 800 oC for multiple cycles) attributed to the strong metal-support interaction (SMSI) and unsaturated Pd metal sites caused by the shorter Pd-O distance. Mechanism studies determine that the Pd/CeO2-SCC-R possesses highly-efficient C-C cleavage ability owing to the persistent formation of large amounts of oxygen vacancies and low-coordinated Pd species, and the addition of H2O intrinsically accelerates propane activation and intermediate mineralization attributed to suppression of by-products by OH species. In comparison, the Pd single atom/CeO2 catalyst is preferentially for C-H bonds cleavage and inactive for C-C bonds cracking due to the saturated Pd sites anchored to the oxygen of supports directly, which generates more non-oxidation by-products as propyne and propylene, inhibiting the continuous decomposition of propane due to the retardatory oxidation of pyruvate species. The present work sheds critical insight to the production of fulfilling products through the directional cleavage of C-C/C-H bonds in the activation of light alkane molecules. © 2022, The Authors. All rights reserved.

关键词： Oxygen vacancies

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Fabrication of highly reliable jointbased on Cu@Ni@Sn double-layerpowderfor high temperature application

Fabrication of highly reliable jointbased on Cu@Ni@Sn double...

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作者： Xu, Hongyan Shen, Yaochun Hu, Yihua Li, Jianqiang Xu, Ju Beijing Engineering Laboratory of Electrical Drive System & Power Electronic Device Packaging Technology Micro-nano fabrication technology department Institute of Electronic Engineering Chinese Academy of Sciences Beijing 100190 China School of Electrical Engineering Electronics andComputer Science University of Liverpool LiverpoolL69 3GJ United Kingdom State Key Laboratory of Multiphase Complex System Institute of Process Engineering Chinese Academy of Sciences Beijing100190 China University of Chinese Academy of Sciences Beijing100049 China

A highly reliable three-dimensional networkstructure jointwas fabricatedbased on Cu@Ni@Sn core-shell powderand transient liquid phase bonding (TLPB) technologyfor high temperature application. Cu@Ni@Sn joint is characterized by Cu metal particles embedded in the matrix of (Cu,Ni)6Sn5/Ni3Sn4intermetallics (IMCs), low level of voiding is achieved, they can be reflowed at a low temperatures( © 2019 IMAPS-International Microelectronics and Packaging Society. All rights reserved.

关键词： High temperature applications

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Simultaneous Analysis of Swirl Spray Dynamics Using a Telecentric System

SSRN

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SSRN 2023年

作者： Machado, Danilo Almeida de Souza Costa, Fernando Dias, Gabriel Silva Mota, Fábio A.S. Combustion and Propulsion Laboratory National Institute for Space Research SP Cachoeira Paulista12630-000 Brazil State Key Laboratory of Multiphase Flows in Power Engineering Xi’an Jiaotong University Shanxi Xi’an710049 China

A telecentric shadowgraphy optical system was utilized to determine macroscopic and microscopic parameters of sprays and the measurement of conical liquid films formed by dual pressure swirl injectors. Spray cone angles, breakup lengths, mean droplet velocities, momentum flows, wave amplitude ratios and maximum wave growth rates were simultaneously measured using high-speed images with kHz frequencies. Two injectors were tested with inner nozzles having Abramovich geometric constants Kint = 2 and 2.125 and external nozzles with geometric constants Kext = 2.9 and 1.9792, respectively. Injection pressures were varied from 0.05 to 0.5 MPa and water was used as test fluid. The experimental data indicate that the breakup length, droplet velocity, flow momentum and disturbance amplitude ratio are higher for injectors with larger mass flow rates, for a given injection pressure. The maximum amplitude ratios of the conical liquid film disturbances varied in the range 2.32 © 2023, The Authors. All rights reserved.

关键词： Liquid films

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Simultaneous Analysis of Liquid Film Instabilities and Properties of Swirl Sprays by Telecentric Shadowgraphy

SSRN

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SSRN 2023年

作者： Machado, Danilo Almeida Costa, Fernando S. Dias, Gabriel Silva Mota, Fábio A.S. Combustion and Propulsion Laboratory National Space Research Institute SP Cachoeira Paulista12630-000 Brazil State Key Laboratory of Multiphase Flows in Power Engineering Xi’an Jiaotong University Shanxi Xi’an710049 China

A telecentric shadowgraphy optical system was utilized to determine macroscopic and microscopic parameters of sprays and the measurement of conical liquid films formed by dual pressure swirl injectors. Spray cone angles, breakup lengths, mean droplet velocities, momentum flows, wave amplitude ratios and maximum wave growth rates were simultaneously measured using high-speed images with kHz frequencies. Two injectors were tested with inner nozzles having Abramovich geometric constants Kint = 2 and 2.125 and external nozzles with geometric constants Kext = 2.9 and 1.9792, respectively. Injection pressures were varied from 0.05 to 0.5 MPa and water was used as test fluid. The experimental data indicate that the breakup length, droplet velocity, flow momentum and disturbance amplitude ratio are higher for injectors with larger mass flow rates, for a given injection pressure. On the other hand, the maximum wave growth rate of the liquid film is higher for injectors with smaller mass flow rates. The maximum amplitude ratios of the conical liquid film disturbances varied in the range 2.32 © 2023, The Authors. All rights reserved.

关键词： Liquid films

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Simultaneous Analysis of Liquid Film Instabilities and Properties of Swirl Sprays by Telecentric Shadowgraphy

SSRN

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SSRN 2023年

作者： Machado, Danilo Almeida Costa, Fernando S. Dias, Gabriel Silva Mota, Fábio A.S. Combustion and Propulsion Laboratory National Institute for Space Research SP Cachoeira Paulista12630-000 Brazil State Key Laboratory of Multiphase Flows in Power Engineering Xi’an Jiaotong University Shanxi Xi’an710049 China

关键词： Liquid films

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Three-dimensional analysis of condensation nanofluid film on an inclined rotating disk by efficient analytical methods

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Arab Journal of Basic and Applied Sciences 2018年第1期25卷 28-37页

作者： Hatami, M. Jing, D. Yousif, Majeed A. Department of Mechanical Engineering Esfarayen University of Technology Esfarayen Iran State Key Laboratory of Multiphase Flow in Power Engineering & International Research Center for Renewable Energy Xi’an Jiaotong University Xi’an China Department of Mathematics Faculty of Science University of Zakho Zakho Iraq

In this study, least square method (LSM) and differential transform method (DTM) applied to solve the three dimensional problem of steady nanofluid deposition on an inclined rotating disk is illustrated. The governing non-linear partial differential equations are reduced to the nonlinear ordinary differential equations system by similarity transform. There is a good agreement between the present analytical and numerical results. Results indicate that increasing nanofluid volume fraction leads to increase in temperature profile and highest temperature obtained for aluminium oxide (Al₂O₃)-water case. © 2018, © 2018 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group on behalf of the University of Bahrain.

关键词： condensation film DTM film thickness LSM Nanofluid rotating disk

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