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MoC nanocrystals confined in N-doped carbon nanosheets toward highly selective electrocatalytic nitric oxide reduction to ammonia

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Nano Research 2022年第10期15卷 8890-8896页

作者： Ge Meng Mengmeng Jin Tianran Wei Qian Liu Shusheng Zhang xianyun peng Jun Luo Xijun Liu Key Laboratory of Carbon Materials of Zhejiang Province College of Chemistry and Materials EngineeringWenzhou UniversityWenzhou 325035China Institute for New Energy Materials and Low-Carbon Technologies Tianjin Key Lab for Photoelectric Materials&DevicesSchool of Materials Science and EngineeringTianjin University of TechnologyTianjin 300384China MOE Key Laboratory of New Processing Technology for Non-Ferrous Metals and Materials and Guangxi Key Laboratory of Processing for NonFerrous Metals and Featured MaterialsSchool of ResourceEnvironments and MaterialsGuangxi UniversityNanning 530004China Institute for Advanced Study Chengdu UniversityChengdu 610106China College of Chemistry Zhengzhou UniversityZhengzhou 450000China Institute of Zhejiang University–Quzhou Quzhou 324000China

Electrochemical nitric oxide reduction reaction(NORR)to produce ammonia(NH3)under ambient conditions is a promising alternative to the energy and carbon-intensive Haber–Bosch approach,but its performance is still improved.Herein,molybdenum carbides(MoC)nanocrystals confined by nitrogen-doped carbon nanosheets are first designed as an efficient and durable electrocatalyst for catalyzing the reduction of NO to NH3 with maximal Faradaic efficiency of 89%±2%and a yield rate of 1,350±15μg·h^(−1)·cm^(−2) at the applied potential of−0.8 V vs.reversible hydrogen electrode(RHE)as well as high stable activity with negligible current density and NH3 yield rate decays over a 30 h continue the test.Moreover,as a proof-of-concept of Zn–NO battery,it achieves a peak power density of 1.8 mW·cm^(−2) and a large NH3 yield rate of 782±10μg·h^(−1)·cm^(−2),which are comparable to the best-reported results.Theoretical calculations reveal that the MoC(111)has a strong electronic interaction with NO molecules and thus lowering the energy barrier of the potential-determining step and suppressing hydrogen evolution kinetics.This work suggests that Mo-based materials are a powerful platform providing great opportunities to explore highly selective and active catalysts for NH3 production.

关键词： ammonia electrosynthesis green route molybdenum carbides(MoC)nanocrystals nitric oxide reduction reaction high selectivity

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Rational design on photoelectrodes and devices to boost photoelectrochemical performance of solar-driven water splitting: a mini review

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Frontiers of Chemical Science and Engineering 2022年第6期16卷 777-798页

作者： Siliu Lyu Muhammad Adnan Younis Zhibin Liu Libin Zeng xianyun peng Bin Yang Zhongjian Li Lecheng Lei Yang Hou Key Laboratory of Biomass Chemical Engineering of Ministry of Education College of Chemical and Biological EngineeringZhejiang UniversityHangzhou 310027China Institute of Zhejiang University-Quzhou Quzhou 324000China

As an eco-friendly,efficient,and low-cost technique,photoelectrochemical water splitting has attracted growing interest in the production of clean and sustainable hydrogen by the conversion of abundant solar energy.In the photoelectrochemical system,the photoelectrode plays a vital role in absorbing the energy of sunlight to trigger the water splitting process and the overall efficiency depends largely on the integration and design of photoelectrochemical devices.In recent years,the optimization of photoelectrodes and photoelectrochemical devices to achieve highly efficient hydrogen production has been extensively investigated.In this paper,a concise review of recent advances in the modification of nanostructured photoelectrodes and the design of photoelectrochemical devices is presented.Meanwhile,the general principles of structural and morphological factors in altering the photoelectrochemical performance of photoelectrodes are discussed.Furthermore,the performance indicators and first principles to describe the behaviors of charge carriers are analyzed,which will be of profound guiding significance to increasing the overall efficiency of the photoelectrochemical water splitting system.Finally,current challenges and prospects for an in-depth understanding of reaction mechanisms using advanced characterization technologies and potential strategies for developing novel photoelectrodes and advanced photoelectrochemical water splitting devices are demonstrated.

关键词： photoelectrochemical water splitting photoelectrodes hydrogen production charge separation catalytic mechanism

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Single‐atomic Co‐B_(2)N_(2)sites anchored on carbon nanotube arrays promote lithium polysulfide conversion in lithium-sulfur batteries

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Carbon Energy 2023年第11期5卷 31-43页

作者： Zhifeng Wang Yajing Yan Yongguang Zhang Yanxu Chen xianyun peng Xin Wang Weimin Zhao Chunling Qin Qian Liu Xijun Liu Zhongwei Chen Key Laboratory for New Type of Functional Materials in Hebei Province School of Materials Science and EngineeringHebei University of TechnologyTianjinChina Tianjin Key Lab for Photoelectric Materials&Devices Institute for New Energy Materials&Low‐Carbon TechnologiesSchool of Materials Science and EngineeringTianjin University of TechnologyTianjinChina South China Academy of Advanced Optoelectronics International Academy of Optoelectronics at ZhaoqingSouth China Normal UniversityGuangdongChina Institute for Advanced Study Chengdu UniversityChengduSichuanChina MOE Key Laboratory of New Processing Technology for Non‐Ferrous Metals and Materials Guangxi Key Laboratory of Processing for Non‐Ferrous Metals and Featured MaterialsSchool of ResourceEnvironments and MaterialsGuangxi UniversityNanningChina Department of Chemical Engineering University of WaterlooWaterlooOntarioCanada

Due to low cost,high capacity,and high energy density,lithium–sulfur(Li–S)batteries have attracted much attention;however,their cycling performance was largely limited by the poor redox kinetics and low sulfur utilization.Herein,predicted by density functional theory calculations,single‐atomic Co‐B2N2 site‐imbedded boron and nitrogen co‐doped carbon nanotubes(SA‐Co/BNC)were designed to accomplish high sulfur loading,fast kinetic,and long service period Li–S batteries.Experiments proved that Co‐B2N2 atomic sites can effectively catalyze lithium polysulfide conversion.Therefore,the electrodes delivered a specific capacity of 1106 mAh g−1 at 0.2 C after 100 cycles and exhibited an outstanding cycle performance over 1000 cycles at 1 C with a decay rate of 0.032%per cycle.Our study offers a new strategy to couple the combined effect of nanocarriers and single‐atomic catalysts in novel coordination environments for high‐performance Li–S batteries.

关键词： carbon nanotubes coordination environment engineering density functional theory calculation lithium-sulfur batteries single‐atom catalys

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Atomic Fe-Zn dual-metal sites for high-efficiency pH-universal oxygen reduction catalysis

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Nano Research 2021年第5期14卷 1374-1381页

作者： Jie Xu Shuhua Lai Defeng Qi Min Hu xianyun peng Yifan Liu Wei Liu Guangzhi Hu Heng Xu Fan Li Chao Li Jia He Longchao Zhuo Jiaqiang Sun Yuan Qiu Shusheng Zhang Jun Luo Xijun Liu Institute for New Energy Materials&Low-Carbon Technologies and Tianjin Key Lab of Photoelectric Materials&Devices School of Materials Science and EngineeringTianjin University of TechnologyTianjin300384China College of Physics and Optoelectronic Engineering Shenzhen UniversityShenzhen518060China Institute for Ecological Research and Pollution Control of Plateau Lakes School of Ecology and Environmental ScienceYunnan UniversityKunming650504China School of Materials Science and Engineering Xi’an University of TechnologyXi’an710048China State Key Laboratory of Coal Conversion Institute of Coal ChemistryChinese Academy of SciencesTaiyuan030001China College of Chemistry Zhengzhou UniversityZhengzhou450000China

An effective electrocatalyst being highly active in all pH range for oxygen reduction reaction(ORR)is crucial for energy conversion and storage devices.However,most of the high-efficiency ORR catalysis was reported in alkaline conditions.Herein,we demonstrated the preparation of atomically dispersed Fe-Zn pairs anchored on porous N-doped carbon frameworks(Fe-Zn-SA/NC),which works efficiently as ORR catalyst in the whole pH range.It achieves high half-wave potentials of 0.78,0.85 and 0.72 V in 0.1 M HClO4,0.1 M KOH and 0.1 M phosphate buffer saline(PBS)solutions,respectively,as well as respectable stability.The performances are even comparable to Pt/C.Furthermore,when assembled into a Zn-air battery,the high power density of 167.2 mWcm−2 and 120 h durability reveal the feasibility of Fe-Zn-SA/NC in real energy-related devices.Theoretical calculations demonstrate that the superior catalytic activity of Fe-Zn-SA/NC can be contributed to the lower energy barriers of ORR at the Fe-Zn-N6 centers.This work demonstrates the potential of Fe-Zn pairs as alternatives to the Pt catalysts for efficient catalytic ORR and provides new insights of dual-atom catalysts for other energy conversion related catalytic reactions.

关键词： Fe-Zn atomic pairs oxygen reduction reaction pH-universal Zn-air battery electrocatalysis

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Microstructures and hydrogen storage properties of as-cast and copper-mould-cast LaMg_4Ni alloys

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Journal of Rare Earths 2014年第5期32卷 434-438页

作者：范燕平彭显云刘宝忠宿太超哈日巴拉 School of Materials Science and Engineering Henan Polytechnic University Cultivating Base for Key Laboratory of Environment-friendly Inorganic Materials in University of Henan Province Henan Polytechnic University

Phase compositions, morphologies and hydrogen storage properties of the as-cast and copper-mould-cast LaMgaNi alloys were studied. The dehydriding onset temperature of the as-cast alloy hydride was about 500 K, which was at least 50 K higher than that of the copper-mould-cast one, and the copper-mould-cast alloy hydride had a faster dehydriding rate compared with as-cast one. Additionally, the copper-mould-cast alloy could uptake 2.85 wt.% hydrogen, which was 95.0% of saturated hydrogen storage capac- ity at room temperature. While only 1.80 wt.% hydrogen （60% of saturated capacity） was absorbed for the as-cast alloy under the same conditions. The reversible hydrogen storage capacities and plateau hydrogen pressures of the two alloys were close. X-ray dif- fractions and scanning electron microscopy results indicated that similar thermodynamic property of the two alloys should be ascribed to the same hydrogen storage phase, Mg and MgzNi. The better hydrogen sorption kinetics of copper-mould-cast alloy should be as- cribed to the more uniform phase distribution compared with that of the as-cast one.

关键词： hydrogen storage copper-mould-cast La-Mg-Ni alloy kinetics thermodynamics rare earths

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Dual effects of spatial updating in both real and virtual environments

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Chinese Science Bulletin 2013年第8期58卷 898-906页

作者： LIU ShuQing ZHENG XianJun Sam LIU xianyun peng KaiPing Department of Psychology Tsinghua University Academy of Psychology and Behaviour Tianjin Normal University Department of Psychology University of California

When people move around in their environment, spatial updating, which is an automatic cognitive process, is essential to ensuring people can keep track of their relations between them and the surrounding objects, and to "recalculating" the relative position and orientation of those objects with regard to the current position of the persons. Despite the facilitating effect of spatial updating to people's mental representation in most circumstances as demonstrated in most of the existing literature, the effect sometimes can be adversarial. For instance, some research suggested that even though people were asked to ignore their locomotion, it is difficult to suppress updating of the spatial representation during movement. The current two studies were conducted to systematically investigate the dual effects of spatial updating in both real and virtual environments. We used a typical spatial updating paradigm to explore the effects of scene familiarity (familiar vs. novel) and person's locomotion (stationary vs. moving) on change detection accuracy (target object moved or not). The results indicated a facilitating effect of spatial updating in the novel scene condition, but an adversarial effect in the familiar scene condition-the dual effects, in both real and virtual environments.

关键词：虚拟环境空间重影运动过程相对位置对象移动认知过程心理表征

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跨国公司R&D国际化对我国企业创新网络结构的影响

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中国科技论坛 2009年第8期 63-67页

作者：曾德明禹献云彭盾湖南大学工商管理学院湖南长沙410082

在新一轮全球科技资源流动和重组推动下,跨国公司致力于R&D活动国际化,逐步介入到我国企业创新网络中,并从两个层面对我国企业创新网络产生影响。核心网络层面:跨国公司R&D单元的介入增加了核心网络的创新主体数量,并影响创新主体之间... 详细信息

在新一轮全球科技资源流动和重组推动下,跨国公司致力于R&D活动国际化,逐步介入到我国企业创新网络中,并从两个层面对我国企业创新网络产生影响。核心网络层面:跨国公司R&D单元的介入增加了核心网络的创新主体数量,并影响创新主体之间的联结机制;辅助网络层面:跨国公司R&D单元与辅助网络支撑机构形成新的联结,在一定程度上改变了辅助网络的功能与行为,促进其更好地发挥辅助作用。通过对这两个层面的作用,跨国公司的R&D国际化活动有力地推动了我国企业创新网络结构的演化。

关键词：跨国公司 R&D国际化创新网络结构核心网络辅助网络

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PCB版图设计中的结构建模方法研究

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微电子学 2010年第1期40卷 98-102页

作者：李贤云余兴六吴鹏中国电子科技集团公司第二十四研究所重庆400060

针对PCB版图设计中如何考虑结构匹配的问题,基于Mentor Graphics Expedition版图设计软件,分析了PCB版图设计中版图与结构协同设计的基本原理,提出了结构建模的一般方法;以实际应用为例,阐述了三种典型结构的具体建模方法。对平面近似... 详细信息

针对PCB版图设计中如何考虑结构匹配的问题,基于Mentor Graphics Expedition版图设计软件,分析了PCB版图设计中版图与结构协同设计的基本原理,提出了结构建模的一般方法;以实际应用为例,阐述了三种典型结构的具体建模方法。对平面近似分割法产生的曲面空间结构模型进行了精度和可信度分析。

关键词：印刷电路板结构建模平面近似分割法结构匹配

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高精度陀螺仪力矩器线圈骨架车铣复合加工工艺与实现

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中国惯性技术学报 2019年第6期27卷 787-792页

作者：李立杰马明山陈鹏姚鑫王宪云天津航海仪器研究所

某型宇航陀螺仪力矩器核心零件线圈骨架所用材料为微晶玻璃,其外圆线槽的分度精度以及与内孔的同轴精度直接影响力矩器的工作精度,但在实际加工中一直存在着线槽分度精度和同轴度超差的问题。针对力矩器线圈骨架的加工难题,通过对力矩... 详细信息

某型宇航陀螺仪力矩器核心零件线圈骨架所用材料为微晶玻璃,其外圆线槽的分度精度以及与内孔的同轴精度直接影响力矩器的工作精度,但在实际加工中一直存在着线槽分度精度和同轴度超差的问题。针对力矩器线圈骨架的加工难题,通过对力矩器线圈骨架结构以及现有加工方案进行分析,将车铣复合加工方法引入到力矩器线圈骨架的加工中。采用内孔和外圆线槽一次装卡加工的方案,设计了车铣复合加工工装,通过正确选取加工设备,优化设计走刀路径、切削参数和冷却系统,提高了力矩器线圈骨架外圆线槽的分度精度以及与内孔同轴精度,并将工件单件加工时间从6 h缩短至4 h,验证了车铣复合加工方案的合理性。目前,该项工艺方法已应用于某型高精度宇航陀螺线圈骨架的批量加工。

关键词：车铣复合硬脆材料微晶玻璃分度同轴

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功率型白光LED可靠性的实验及仿真建模研究

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固体电子学研究与进展 2020年第1期40卷 43-47页

作者：彭聪刘宪云夏丽方佳怡戚伟常州大学信息数理学院江苏常州213164 浙江大学城市学院信息与电气工程学院杭州310000

快速推广LED产品到照明市场最主要的障碍在于长期的可靠性测试问题。由于长期的LED可靠性测试不符合快速且低成本的要求,因此本实验对白光LED进行步进式加速寿命老化测试,步进式环境温度从55oC到145oC变化。同时,对LED进行结温测试,并使... 详细信息

快速推广LED产品到照明市场最主要的障碍在于长期的可靠性测试问题。由于长期的LED可靠性测试不符合快速且低成本的要求,因此本实验对白光LED进行步进式加速寿命老化测试,步进式环境温度从55oC到145oC变化。同时,对LED进行结温测试,并使用COMSOL仿真软件进行温度场分布仿真来模拟器件的发热情况,结果表明荧光胶处的温度高于LED芯片温度。在长期老化之后,对LED的光度进行测量,可以对LED的失效机理进行分析。通过研究温度对LED的光谱功率分布衰减的影响及光通量衰减的影响,发现在经过近3500 h的老化之后,LED的光衰很严重,表明电流及高温对LED的影响是极大的。

关键词：发光二极管老化测试 COMSOL 光度

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