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Unveiling the role of Zn dopants in NiFe phosphide nanosheet for oxygen evolution reaction

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Progress in Natural Science:Materials International 2023年第1期33卷 74-82页

作者： Chendong Kou Jingrui Han Haibin Wang Mei Han Hongyan Liang School of Materials Science and Engineering Tianjin University Key Laboratory of Efficient Utilization of Low and Medium Grade Energy Tianjin University

Transition metal phosphides have been recognized as promising electrocatalysts for oxygen evolution reaction(OER) due to their low cost and high activity. However, the insufficient exposed active region limited the OER performance. Recently, the introduction of sacrificial dopants has been considered an effective strategy to enlarge the surface area. Herein, the Zn dopants are introduced in NiFe phosphide(NiFeZnP) nanosheet, which work as the sacrificial dopants to generate more exposed active NiFe sites and promote the formation of the NiFeOOH active phase during OER process. The optimized Zn-doped NiFeP catalyst shows an overpotential of ≈203 mV to reach a current density of 10 mA cm-2in 1 M KOH, and a stability of 100 h at 1000 mA cm-2. Overall, this work provides a sacrificial Zn doping strategy to prepare highly efficient OER electrocatalysts.

关键词： Transition metal phosphide Sacrificial dopant Self-supported electrode Oxygen evolution reaction

The heat transfer optimization of conical fin by shape modification

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Chinese Journal of Chemical Engineering 2016年第8期24卷 972-978页

作者： Jiansheng Wang Xiao Wang Key Laboratory of Efficient Utilization of Low and Medium Grade Energy MOE School of Mechanical Engineering Tianjin University

In present work, a stepping optimization algorithm is proposed for the geometric optimization of conical fin, and the heat transfer rate of the fin is treated as the objective function in the optimization algorithm. The conical fin is divided into finite elements which have different generatrix slopes, and the geometry of the conical fin is finally determined by ensuring that every divided element can maintain the maximum heat transfer rate. Based on the actual condition of every element of the fin, the heat conduction equation is solved step by step. The present result shows that the optimized conical fin has more heat transfer quantity and higher fin efficiency compared with those of some typical fins. Furthermore, the theoretical feasibility and the error analysis of present optimization algorithm have been performed as well.

关键词： Fin Optimization Heat transfer Stepping optimization algorithm

Multiple metallic dopants in nickel nanoparticles for electrocatalytic oxygen evolution

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Progress in Natural Science:Materials International 2023年第1期33卷 67-73页

作者： Yan Huang Jingrui Han Haibin Wang Lihua Liu Hongyan Liang School of Materials Science and Engineering Tianjin University Key Laboratory of Efficient Utilization of Low and Medium Grade Energy Ministry of Education Tianjin University College of Innovation and Entrepreneurship Shanghai Jianqiao University

Developing efficient oxygen evolution reaction(OER) electrocatalysts is of great importance for sustainable energy conversion and storage. Ni-based catalysts have shown great potential as OER electrocatalysts, but their performance still needs to be improved. Herein, we report the multiple metal doped nickel nanoparticles synthesized via a simple oil phase strategy as efficient OER catalysts. The FeMnMoV–Ni exhibits superior OER performance with an overpotential of 220 mV at 10 mA cm-2and a long-term stability of 250 h in 1 M KOH solution. In situ Raman analysis shows that the NiOOH site works as the active center and multiple metallic dopants facilitate the formation of NiOOH. Mo and V dopants promote the formation of high-valence state of Ni sites, and Mn dopants increase the electrochemical active surface area and expose more active sites. This work provides a novel strategy for catalyst design, which is critical for developing multiple metal doped catalysts.

关键词： Multiple metallic dopants Oxygen evolution Electrocatalysts In situ Raman Nickel

Method for determining climatic design conditions based on the indoor thermal environment risk level

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能源与人工环境(英文)

能源与人工环境(英文) 2021年第1期2卷 56-64页

作者： Xia Wu Zhe Tian Yuanyuan Wang Jide Niu Chengzhi Tian School of Environmental Science and Engineering Key Laboratory of Efficient Utilization of Low and Medium Grade EnergyMOETianjin UniversityTianjin 300072China

Currently,climatic design conditions are usually selected according to the frequency of climatic parameters them-selves,which method cannot reflect the indoor thermal environment risk level of the building in design.In this regard,the research proposes to construct the correlation between climatic design conditions and indoor thermal environment risk level,and explore the effect of uncertainty in building thermal performance on this correlation from the perspective of probability,thus realizing the process of selecting the climatic design conditions based on the requirement for indoor thermal environment risk level.Taking Guangzhou in China as an example,the new process of determining climatic design conditions is realized.On this basis,the difference between the traditional method and the present research method is compared.In the Chinese norm method,the indoor thermal environ-ment risk level of the building is between 0 and 0.03%when the climatic design conditions are selected with 0.57%cumulative frequency of occurrence;in the research method,the indoor thermal environment risk level of the building is between 0.2%and 0.6%when the climatic design conditions are selected with 0.57%indoor thermal environment risk level and 100%confidence level.The results indicate that the research method can meet the designer’s expectation for indoor thermal environment risk level in design more directly and accurately.

关键词： Air-conditioning system design Climatic design conditions Indoor thermal environment Risk level Building thermal performance

Risk Evaluation of Ammonia Leakage based on Modified Probability Calculation Formulas

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Journal of Thermal Science 2023年第2期32卷 854-865页

作者： GE Yingying YANG Zhao HE Hongxia WU Xiaokun CHEN Yubo LV Zijian ZHANG Yong Key Laboratory of Efficient Utilization of Low and Medium Grade Energy MOESchool of Mechanical EngineeringTianjin UniversityTianjin 300072China State key laboratory of Air-Conditioning Equipment and System energy Conservation GREE Electric AppliancesInc.of ZhuhaiGuangdong 519070China

Due to its flammable,explosive,and corrosive characteristics,fire,and explosion accidents caused by ammonia leakage occur from time to time.In this work,the concentration distribution of the model was calculated according to the existing formula of probabilistic risk assessment.Using the revised formulas,the leakage of the ammonia room was quantitatively analyzed,and different state parameters were analyzed to find out the dangerous leakage points of the ammonia refrigeration system.The results of the calculation are that the existence of obstacles in the space will increase the probability of leakage risk.And the greater the leakage time to the lower flammability limit accounts for the total leakage time,the greater the risk probability.Dangerous leakage in ammonia systems mainly occurs in storage tanks and condensers.The data show that the dynamic mass flow of ammonia leakage decreases with time,and the leakage diameter increases with the increase of leakage pressure.At the same time,the leakage mass increases gradually with the leakage aperture near circular.

关键词： flammable refrigerants leakage risk evaluation of fire probability calculation

Shift-characteristics and bounds of thermal performance of organic Rankine cycle based on trapezoidal model

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Science China(Technological Sciences) 2018年第12期61卷 1802-1813页

作者： LI XinGuo WANG JingYi WU XiaoSong School of Mechanical Engineering Tianjin University Key Laboratory of Efficient Utilization of Low and Medium Grade Energy

In consideration of the constraints of actual working fluids on theoretical study of organic Rankine cycle(ORC), a trapezoidal cycle(TPC) with theoretical model to simulate ORC was proposed in previous works. In this study, mathematical models of working fluids including model of simulated saturation curve(MSSC) and model of linear saturation lines(MLSL) are proposed and built. Combining mathematical models of working fluids and TPC, the thermodynamic characteristics and principles of TPC(or ORC) can be studied or predicted theoretically. There exists a shift-curve of net power output with corresponding shifttemperature of heating fluid for working fluids, which indicates the shift of net power output from having optimum condition of maximum power to monotonic increase with evaporation temperature. This shift-characteristic is significant to working fluid selection and evaluation of cycle performance, for it indicates that cycle without optimum condition can yield higher net power output than the cycle with optimum condition. Equations to calculate the shift-temperature in ORC(or TPC) are derived; and equations to calculate the highest optimal evaporation temperature and highest maximum power as the highest optimum condition at this shift-temperature are obtained. Based on TPC and its theoretical model, the lower and upper bounds of thermal performance(maximum power and corresponding thermal efficiency) of TPC(or ORC) can be demonstrated and acquired. TPC can develop to Carnot cycle or trilateral cycle that it is significant to use TPC as a generalized cycle to study the general principles and characteristics of the cycles.

关键词： organic Rankine cycle (ORC) trapezoidal cycle (TPC) mathematical models of working fluids shift-temperature of heating fluid for working fluid bounds of thermal performance

Lattice mismatch in Ni_(3)Al-based alloy for efficient oxygen evolution

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Journal of Materials Science & Technology 2022年第11期106卷 19-27页

作者： Shicheng Li Hongyan Liang Chong Li Yongchang Liu State key Lab of Hydraulic Engineering Simulation and Safety School of Materials Science&EngineeringTianjin UniversityTianjin 300354China Key Laboratory of Efficient Utilization of Low and Medium Grade Energy Ministry of EducationTianjin UniversityTianjin 300350China

The Ni_(3)Al-based alloy has been considered as a robust catalyst for oxygen evolution reaction(OER)due to its long-term durability and acceptable activity.However,related reports about understanding the catalytic mechanism are rare and desirable.Herein,the effect of γ/γ’phase lattice mismatch on the catalytic performance caused by various cooling rates after solution heat treatment was investigated.With decreasing cooling rate,the morphologies of γ' precipitates transformed from sphere to cube and the lattice mismatch increased from-0.172%to-0.409%.The increased lattice mismatch facilitated the formation of the active β-NiOOH phase and enhanced the intrinsic catalytic activity,resulting in the optimized OER overpotential of 240 mV at a current density of 10 mA cm^(−2) with a Tafel slope of 66.1 mV dec^(−1) and a stability of 200 h in 1 M KOH.This work reveals the lattice mismatch effect on OER and provides a potential candidate for OER.

关键词： Ni_(3)Al alloy γ’precipitates Annealing Oxygen evolution electrocatalysts

Application and development of ground source heat pump technology in China

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Protection and Control of Modern Power Systems 2021年第1期6卷 215-232页

作者： Chaofan Song Yang Li Taha Rajeh Ling Ma Jun Zhao Wenjia Li Key Laboratory of Efficient Utilization of Low and Medium Grade Energy Ministry of Education of ChinaTianjin UniversityTianjin300350China

Ground source heat pumps (GSHPs) are one of the renewable energy technologies with features of high efficiency, energy saving, economic feasibility and environmental protection. In China, GSHPs have been widely used for building heating and cooling in recent years, and have shown great potential for future energy development. This paper summarizes the classification, development history, and use status of shallow GSHPs. Several typical engineering cases of GSHP technology are also specified and analyzed. Finally, promising development trends and some advanced technologies are illustrated.

关键词： Shallow geothermal energy Ground source heat pump Case analysis

Discussion on the Mechanism of Source Integration between Solar energy and Biomass energy with Similar grades

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Journal of Thermal Science 2021年第5期30卷 1607-1613页

作者： ZHAO Li SU Dandan Key Laboratory of Efficient Utilization of Low and Medium Grade Energy(Tianjin University) Ministry of Education of ChinaTianjin300350China

The clean transformation of the China’s energy structure is related to the establishment of China as an energy power in the new world pattern.The multi-energy systems based on renewable energy,especially solar energy and biomass energy,have become a popular energy supply mode.However,there is no clear theoretical guidance for the quantitative source integration of these two types of clean energy.Concretely,whether the source grades of solar energy and biomass energy are similar in different solar energy modes has not been considered yet.Aiming at this problem,based on the theory of space-time unity of the special theory of relativity,a new principle of source integration is proposed,and the corresponding mathematical model is established.The theoretical calculation of the combination of solar energy and different types of biomass energy is carried out.Under the premise of the similarity between the source grades of different biomass energy and solar energy,the specific solar energy concentration ratio is obtained.According to this principle,the matching efficiency of the multi-energy integration for rice and corn plants can be increased by 39.2%and 36.2%,respectively.

关键词： special theory of relativity solar energy biomass energy source integration grade