Liquid hydrogen storage and transportation is an effective method for large-scale transportation and utilization of hydrogen energy. Revealing the flow mechanism of cryogenic working fluid is the key to optimize heat ...Liquid hydrogen storage and transportation is an effective method for large-scale transportation and utilization of hydrogen energy. Revealing the flow mechanism of cryogenic working fluid is the key to optimize heat exchanger structure and hydrogen liquefaction process(LH2). The methods of cryogenic visualization experiment, theoretical analysis and numerical simulation are conducted to study the falling film flow characteristics with the effect of co-current gas flow in LH2spiral wound heat exchanger.The results show that the flow rate of mixed refrigerant has a great influence on liquid film spreading process, falling film flow pattern and heat transfer performance. The liquid film of LH2mixed refrigerant with column flow pattern can not uniformly and completely cover the tube wall surface. As liquid flow rate increases, the falling film flow pattern evolves into sheet-column flow and sheet flow, and liquid film completely covers the surface of tube wall. With the increase of shear effect of gas-phase mixed refrigerant in the same direction, the liquid film gradually becomes unstable, and the flow pattern eventually evolves into a mist flow.展开更多
Developing high-efficiency multifunctional nanomaterials is promising for wide p H hydrogen evolution reaction(HER) and energy storage but still challenging. Herein, a novel in-situ doping-induced lattice strain strat...Developing high-efficiency multifunctional nanomaterials is promising for wide p H hydrogen evolution reaction(HER) and energy storage but still challenging. Herein, a novel in-situ doping-induced lattice strain strategy of NiCoP/S nanocrystals(NCs) was proposed through using seed crystal conversion approach with NiCo_(2)S_(4) spinel as precursor. The small amount of S atoms in NiCoP/S NCs perturbed the local electronic structure, leading to the atomic position shift of the nearest neighbor in the protocell and the nanoscale lattice strain, which optimized the H* adsorption free energy and activated H_(2)O molecules, resulting the dramatically elevated HER performance within a wide p H range. Especially, the NiCoP/S NCs displayed better HER electrocatalytic activity than comical 20% Pt/C at high current density in 1 M KOH and natural seawater: it only needed 266 m V vs. reversible hydrogen electrode(RHE) and660 m V vs. RHE to arrive the current density of 350 m A cm^(-2) in 1 M KOH and natural seawater, indicating the application prospect for industrial high current. Besides, NiCoP/S NCs also displayed excellent supercapacitor performance: it showed high specific capacity of 2229.9 F g^(-1) at 1 A g^(-1) and energy density of87.49 Wh kg^(-1), when assembled into an all-solid-state flexible device, exceeding performance of most transition metal phosphides. This work provides new insights into the regulation in electronic structure and lattice strain for electrocatalytic and energy storage applications.展开更多
The cleanup of carbon tetrachloride(CCl4)in groundwater is challenging due to its high volatility and tendency to form a dense nonaqueous liquid phase.From the engineering applications perspective,the pump-and-treat(P...The cleanup of carbon tetrachloride(CCl4)in groundwater is challenging due to its high volatility and tendency to form a dense nonaqueous liquid phase.From the engineering applications perspective,the pump-and-treat(PAT)technology has substantial advantages owing to its large-scale implementation ability to solve groundwater contamination.However,few studies focused on the variation in chloride contaminants in remediation sites after the contaminated groundwater was pumped and treated.Herein,we monitored the changes in chlorinated contamination in groundwater from 12 aquifers at the field level for 6 months.Considering that the natural attenuation of chlorinated contamination is inseparable from the action of microorganisms,the major environmental factors influencing biodegradation were also evaluated.A redundancy analysis(RDA)showed that inorganic salts(DS,DN,and DF)were the most important factor(>60%)affecting the concentration of chloride contaminants,including the negative correlation between DN and the degradation of contaminants in shallow aquifers.In deep aquifers,DS,DF,and pH explained most of the degradation of chloride contaminants.For bedrock layers,DCl was positively relevant to the chloride contaminants in wells PTJ2 and PTJ10.In addition,EC and DS accounted for 73.2%and 92.4%of the contaminant’s variance in wells PTJ4 and PTJ8,respectively.Moreover,the concentrations of the corresponding contaminations and physicochemical variation in three different depths of aquifers were compared;the shallower aquifers showed a higher biodegradation.The in situ monitoring and analysis of contaminated groundwater in remediation sites under PAT will promote practical wastewater treatment technologies in engineering applications.展开更多
Rational interface engineering is essential for minimizing interfacial nonradiative recombination losses and enhancing device performance.Herein,we report the use of bidentate diphenoxybenzene(DPOB)isomers as surface ...Rational interface engineering is essential for minimizing interfacial nonradiative recombination losses and enhancing device performance.Herein,we report the use of bidentate diphenoxybenzene(DPOB)isomers as surface modifiers for perovskite films.The DPOB molecules,which contain two oxygen(O)atoms,chemically bond with undercoordinated Pb^(2+) on the surface of perovskite films,resulting in compression of the perovskite lattice.This chemical interaction,along with physical regulations,leads to the formation of high-quality perovskite films with compressive strain and fewer defects.This compressive strain-induced band bending promotes hole extraction and transport,while inhibiting charge recombination at the interfaces.Furthermore,the addition of DPOB will reduce the zero-dimensional(OD) Cs_4PbBr_6 phase and produce the two-dimensional(2D) CsPb_(2)Br_5 phase,which is also conducive to the improvement of device performance.Ultimately,the resulting perovskite films,which are strain-released and defect-passivated,exhibit exceptional device efficiency,reaching 10.87% for carbon-based CsPbBr_(3) device,14.86% for carbon-based CsPbI_(2)Br device,22,02% for FA_(0.97)Cs_(0.03)PbI_(3) device,respectively.Moreover,the unencapsulated CsPbBr_(3) PSC exhibits excellent stability under persistent exposure to humidity(80%) and heat(80℃) for over 50 days.展开更多
基金supported by the National Natural Science Foundation of China(52304067,62273213)the Natural Science Foundation of Shandong Province of China(ZR2021QE073)+1 种基金the Natural Science Foundation of Shandong Province for Innovation and Development Joint Funds(ZR2022LZH001)the China Postdoctoral Science Foundation(2023M732111)。
文摘Liquid hydrogen storage and transportation is an effective method for large-scale transportation and utilization of hydrogen energy. Revealing the flow mechanism of cryogenic working fluid is the key to optimize heat exchanger structure and hydrogen liquefaction process(LH2). The methods of cryogenic visualization experiment, theoretical analysis and numerical simulation are conducted to study the falling film flow characteristics with the effect of co-current gas flow in LH2spiral wound heat exchanger.The results show that the flow rate of mixed refrigerant has a great influence on liquid film spreading process, falling film flow pattern and heat transfer performance. The liquid film of LH2mixed refrigerant with column flow pattern can not uniformly and completely cover the tube wall surface. As liquid flow rate increases, the falling film flow pattern evolves into sheet-column flow and sheet flow, and liquid film completely covers the surface of tube wall. With the increase of shear effect of gas-phase mixed refrigerant in the same direction, the liquid film gradually becomes unstable, and the flow pattern eventually evolves into a mist flow.
基金supported by the National Natural Science Foundation of China(22108306,22109090)the Taishan Scholars Program of Shandong Province(tsqn201909065)the Shandong Provincial Natural Science Foundation(ZR2021YQ15,ZR2020QB174)。
文摘Developing high-efficiency multifunctional nanomaterials is promising for wide p H hydrogen evolution reaction(HER) and energy storage but still challenging. Herein, a novel in-situ doping-induced lattice strain strategy of NiCoP/S nanocrystals(NCs) was proposed through using seed crystal conversion approach with NiCo_(2)S_(4) spinel as precursor. The small amount of S atoms in NiCoP/S NCs perturbed the local electronic structure, leading to the atomic position shift of the nearest neighbor in the protocell and the nanoscale lattice strain, which optimized the H* adsorption free energy and activated H_(2)O molecules, resulting the dramatically elevated HER performance within a wide p H range. Especially, the NiCoP/S NCs displayed better HER electrocatalytic activity than comical 20% Pt/C at high current density in 1 M KOH and natural seawater: it only needed 266 m V vs. reversible hydrogen electrode(RHE) and660 m V vs. RHE to arrive the current density of 350 m A cm^(-2) in 1 M KOH and natural seawater, indicating the application prospect for industrial high current. Besides, NiCoP/S NCs also displayed excellent supercapacitor performance: it showed high specific capacity of 2229.9 F g^(-1) at 1 A g^(-1) and energy density of87.49 Wh kg^(-1), when assembled into an all-solid-state flexible device, exceeding performance of most transition metal phosphides. This work provides new insights into the regulation in electronic structure and lattice strain for electrocatalytic and energy storage applications.
基金National Natural Science Foundation of China(grant numbers 52070123)Natural Science Foundation of Shandong Province(ZR2020ME224,ZR2021QE160,ZR2021QB016)Project of Shandong Province Higher Educational Young Innovative Talent Introduction and Cultivation Team.
文摘The cleanup of carbon tetrachloride(CCl4)in groundwater is challenging due to its high volatility and tendency to form a dense nonaqueous liquid phase.From the engineering applications perspective,the pump-and-treat(PAT)technology has substantial advantages owing to its large-scale implementation ability to solve groundwater contamination.However,few studies focused on the variation in chloride contaminants in remediation sites after the contaminated groundwater was pumped and treated.Herein,we monitored the changes in chlorinated contamination in groundwater from 12 aquifers at the field level for 6 months.Considering that the natural attenuation of chlorinated contamination is inseparable from the action of microorganisms,the major environmental factors influencing biodegradation were also evaluated.A redundancy analysis(RDA)showed that inorganic salts(DS,DN,and DF)were the most important factor(>60%)affecting the concentration of chloride contaminants,including the negative correlation between DN and the degradation of contaminants in shallow aquifers.In deep aquifers,DS,DF,and pH explained most of the degradation of chloride contaminants.For bedrock layers,DCl was positively relevant to the chloride contaminants in wells PTJ2 and PTJ10.In addition,EC and DS accounted for 73.2%and 92.4%of the contaminant’s variance in wells PTJ4 and PTJ8,respectively.Moreover,the concentrations of the corresponding contaminations and physicochemical variation in three different depths of aquifers were compared;the shallower aquifers showed a higher biodegradation.The in situ monitoring and analysis of contaminated groundwater in remediation sites under PAT will promote practical wastewater treatment technologies in engineering applications.
基金National Natural Science Foundation of China (62104136, 22179051, 62204098, 52104258)Project of Shandong Province Higher Educational Young Innovative Team (2022KJ218)+3 种基金China Postdoctoral Science Foundation (2023M732104)Qingdao Postdoctoral Funding Program (QDBSH20220201002)Postdoctoral Innovation Project of Shandong Province (SDCX-ZG-202303032)Shandong Provincial Natural Science Foundation (ZR2021ME016)。
文摘Rational interface engineering is essential for minimizing interfacial nonradiative recombination losses and enhancing device performance.Herein,we report the use of bidentate diphenoxybenzene(DPOB)isomers as surface modifiers for perovskite films.The DPOB molecules,which contain two oxygen(O)atoms,chemically bond with undercoordinated Pb^(2+) on the surface of perovskite films,resulting in compression of the perovskite lattice.This chemical interaction,along with physical regulations,leads to the formation of high-quality perovskite films with compressive strain and fewer defects.This compressive strain-induced band bending promotes hole extraction and transport,while inhibiting charge recombination at the interfaces.Furthermore,the addition of DPOB will reduce the zero-dimensional(OD) Cs_4PbBr_6 phase and produce the two-dimensional(2D) CsPb_(2)Br_5 phase,which is also conducive to the improvement of device performance.Ultimately,the resulting perovskite films,which are strain-released and defect-passivated,exhibit exceptional device efficiency,reaching 10.87% for carbon-based CsPbBr_(3) device,14.86% for carbon-based CsPbI_(2)Br device,22,02% for FA_(0.97)Cs_(0.03)PbI_(3) device,respectively.Moreover,the unencapsulated CsPbBr_(3) PSC exhibits excellent stability under persistent exposure to humidity(80%) and heat(80℃) for over 50 days.
