Interfacial solar evaporation holds great promise to address the freshwater shortage.However,most interfacial solar evaporators are always filled with water throughout the evaporation process,thus bringing unavoidable...Interfacial solar evaporation holds great promise to address the freshwater shortage.However,most interfacial solar evaporators are always filled with water throughout the evaporation process,thus bringing unavoidable heat loss.Herein,we propose a novel interfacial evaporation structure based on the micro–nano water film,which demonstrates significantly improved evaporation performance,as experimentally verified by polypyrrole-and polydopamine-coated polydimethylsiloxane sponge.The 2D evaporator based on the as-prepared sponge realizes an enhanced evaporation rate of 2.18 kg m^(−2)h^(−1)under 1 sun by fine-tuning the interfacial micro–nano water film.Then,a homemade device with an enhanced condensation function is engineered for outdoor clean water production.Throughout a continuous test for 40 days,this device demonstrates a high water production rate(WPR)of 15.9–19.4 kg kW^(−1)h^(−1)m^(−2).Based on the outdoor outcomes,we further establish a multi-objective model to assess the global WPR.It is predicted that a 1 m^(2)device can produce at most 7.8 kg of clean water per day,which could meet the daily drinking water needs of 3 people.Finally,this technology could greatly alleviate the current water and energy crisis through further large-scale applications.展开更多
Microwave absorbing materials(MAMs)with wide effective absorption bandwidth(EAB)and low filling ratio are highly desirable for practical applications.Rational design in components and structures is one of the effectiv...Microwave absorbing materials(MAMs)with wide effective absorption bandwidth(EAB)and low filling ratio are highly desirable for practical applications.Rational design in components and structures is one of the effective strategies to achieve MAMs with high performance.Herein,double-shelled hollow(DSH)polypyrrole(PPy)nanotubes were synthesized with hydrochloric acid(HCl)and sodium pstyrene sulfonate(SS)co-doping polymerization process using manganese dioxide(MnO_(2))nanorods as a self-sacrifice template.With the increase of HCl concentration,the 1D MnO_(2) core diminishes gradually to form the MnO_(2)@PPy coaxial nanostructures and finally the DSH PPy nanotube,which tunes the microwave absorption performance.Importantly,the DSH PPy nanotubes exhibit excellent microwave absorption of an optimal reflection loss of–50.4 dB and a wide EAB of 7.7 GHz with a low filling ratio of 5 wt%in a paraffin wax matrix.The excellent microwave absorption is believed to be mainly attributed to the enhanced synergistic effects of interfacial polarization and conduction loss arising from the unique DSH structure and the co-doping polymerization.展开更多
This study investigates the influence of electropolymerization conditions on the deposition of polypyrrole(PPy)onto cotton-derived carbon fiber(CF)modified with reduced graphene oxide(rGO)for supercapacitors applicati...This study investigates the influence of electropolymerization conditions on the deposition of polypyrrole(PPy)onto cotton-derived carbon fiber(CF)modified with reduced graphene oxide(rGO)for supercapacitors applications using an experimental/theorical approach.The surface modification of CF by rGO and/or by PPy electrodeposited at 10,25 and 50 mV s^(-1) was thoroughly examined physicochemical and electrochemically.Composite electrodes comprising CF-rGo-PPy,synthesized via electropolymerization at 25 mV s^(-1),demonstrated a remarkable increase in capacitance,showcasing~742 F g^(-1) compared to 153 F g^(-1) for CF.SEM,N_(2)-surface area,XPS,and TD-DFT approach revealed that the higher capacitance observed in CF-rGo-PPy electrodes underscores the influence of morphology and charged nitrogen species on the electrochemical performance of these modified electrodes.Notably,this electrode material achieves a specific capacitance retention of~96%of their initial capacitance after 10000 cycles at 0.5 A g^(-1) measured in a two-electrodes cell configuration.This work also discusses the influence of the scan rate used for pyrrole electropolymerization on the pseudocapacitance contribution of PPy and its possible effect on the porosity of the material.These results highlight the importance of appropriate electropolymerization conditions that allow obtaining the synergistic effect between CF,rGO and PPy.展开更多
基金supported by the National Natural Science Foundation of China(No.52070162)the National Key Research and Development Program of China(2018YFA0901300).
文摘Interfacial solar evaporation holds great promise to address the freshwater shortage.However,most interfacial solar evaporators are always filled with water throughout the evaporation process,thus bringing unavoidable heat loss.Herein,we propose a novel interfacial evaporation structure based on the micro–nano water film,which demonstrates significantly improved evaporation performance,as experimentally verified by polypyrrole-and polydopamine-coated polydimethylsiloxane sponge.The 2D evaporator based on the as-prepared sponge realizes an enhanced evaporation rate of 2.18 kg m^(−2)h^(−1)under 1 sun by fine-tuning the interfacial micro–nano water film.Then,a homemade device with an enhanced condensation function is engineered for outdoor clean water production.Throughout a continuous test for 40 days,this device demonstrates a high water production rate(WPR)of 15.9–19.4 kg kW^(−1)h^(−1)m^(−2).Based on the outdoor outcomes,we further establish a multi-objective model to assess the global WPR.It is predicted that a 1 m^(2)device can produce at most 7.8 kg of clean water per day,which could meet the daily drinking water needs of 3 people.Finally,this technology could greatly alleviate the current water and energy crisis through further large-scale applications.
基金supported by the National Natural Science Foundation of China(No.22165032 and 22265031)the Applied Basic Research Fund of Yunnan Province(No.2019FB129)the Major Science and Technology Project of Precious Metal Materials Genetic Engineering in Yunnan Province(No.2021102AB080019-2)。
文摘Microwave absorbing materials(MAMs)with wide effective absorption bandwidth(EAB)and low filling ratio are highly desirable for practical applications.Rational design in components and structures is one of the effective strategies to achieve MAMs with high performance.Herein,double-shelled hollow(DSH)polypyrrole(PPy)nanotubes were synthesized with hydrochloric acid(HCl)and sodium pstyrene sulfonate(SS)co-doping polymerization process using manganese dioxide(MnO_(2))nanorods as a self-sacrifice template.With the increase of HCl concentration,the 1D MnO_(2) core diminishes gradually to form the MnO_(2)@PPy coaxial nanostructures and finally the DSH PPy nanotube,which tunes the microwave absorption performance.Importantly,the DSH PPy nanotubes exhibit excellent microwave absorption of an optimal reflection loss of–50.4 dB and a wide EAB of 7.7 GHz with a low filling ratio of 5 wt%in a paraffin wax matrix.The excellent microwave absorption is believed to be mainly attributed to the enhanced synergistic effects of interfacial polarization and conduction loss arising from the unique DSH structure and the co-doping polymerization.
基金CONCYTEC and PROCIENCIA agencies from Peru in the framework of the call for Basic Research Projects2019-01[contract number401-2019-FONDECYT].
文摘This study investigates the influence of electropolymerization conditions on the deposition of polypyrrole(PPy)onto cotton-derived carbon fiber(CF)modified with reduced graphene oxide(rGO)for supercapacitors applications using an experimental/theorical approach.The surface modification of CF by rGO and/or by PPy electrodeposited at 10,25 and 50 mV s^(-1) was thoroughly examined physicochemical and electrochemically.Composite electrodes comprising CF-rGo-PPy,synthesized via electropolymerization at 25 mV s^(-1),demonstrated a remarkable increase in capacitance,showcasing~742 F g^(-1) compared to 153 F g^(-1) for CF.SEM,N_(2)-surface area,XPS,and TD-DFT approach revealed that the higher capacitance observed in CF-rGo-PPy electrodes underscores the influence of morphology and charged nitrogen species on the electrochemical performance of these modified electrodes.Notably,this electrode material achieves a specific capacitance retention of~96%of their initial capacitance after 10000 cycles at 0.5 A g^(-1) measured in a two-electrodes cell configuration.This work also discusses the influence of the scan rate used for pyrrole electropolymerization on the pseudocapacitance contribution of PPy and its possible effect on the porosity of the material.These results highlight the importance of appropriate electropolymerization conditions that allow obtaining the synergistic effect between CF,rGO and PPy.
