Self-supported nanoarrays have emerged as a promising alternative electrocatalyst for alkaline H_(2)O splitting,owing to their accessible active sites and strongly coupled interfaces with current collectors for improv...Self-supported nanoarrays have emerged as a promising alternative electrocatalyst for alkaline H_(2)O splitting,owing to their accessible active sites and strongly coupled interfaces with current collectors for improved mass transfer and stability.Herein,self-supported crystalline/amorphous NiO/Ni(OH)_(2)nanosheet arrays on nickel foam(NF)are fabricated via an in-situ dissolution-deposition hydrothermal growing of Ni(OH)_(2)nanosheets without additional metal sources assisted by a common Lewis base,EDTA,followed by a rapid calcination at 300℃in air.The as-prepared EDTA-NF-12 h exhibits high OER and HER performance under alkaline conditions,requiring 235 mV and 158 mV,respectively,to reach 10 mA cm^(-2),and the decent performance can be maintained for 24 h without obvious degradation.The dual interfaces,i.e.,the dense crystalline/amorphous interfaces within the NiO/Ni(OH)_(2)nanosheet arrays,as well as the intimate interfaces between nanoarrays and NF,both serve as reaction active sites,facilitate electron transfer,and endow the catalyst with high activity and stability.Furthermore,by applying EDTA-Ni^(2+)and other Lewis bases with varying basicities instead of EDTA,the interfaces with the NF substrate are found to promote the formation of crystalline/amorphous interfaces within the nanosheets.This study offers appealing opportunities for tailoring the electrocatalytic performance of self-supported electrodes via dual interface engineering.展开更多
Achieving simultaneous reduction of NOx,CO and unburned hydrocarbon(UHC) emissions without compromising engine performance at part loads is the current focus of dual fuel engine research.The present work focuses on an...Achieving simultaneous reduction of NOx,CO and unburned hydrocarbon(UHC) emissions without compromising engine performance at part loads is the current focus of dual fuel engine research.The present work focuses on an experimental investigation conducted on a dual fuel(diesel-natural gas) engine to examine the simultaneous effect of inlet air pre-heating and exhaust gas recirculation(EGR) ratio on performance and emission characteristics at part loads.The use of EGR at high levels seems to be unable to improve the engine performance at part loads.However,it is shown that EGR combined with pre-heating of inlet air can slightly increase thermal efficiency,resulting in reduced levels of both unburned hydrocarbon and NOx emissions.CO and UHC emissions are reduced by 24% and 31%,respectively,The NOx emissions decrease by 21% because of the lower combustion temperature due to the much inert gas brought by EGR and decreased oxygen concentration in the cylinder.展开更多
Great efforts have been made to resolve the serious environmental pollution and inevitable declining of energy resources. A review of Chinese fuel reserves and engine technology showed that compressed natural gas (CN...Great efforts have been made to resolve the serious environmental pollution and inevitable declining of energy resources. A review of Chinese fuel reserves and engine technology showed that compressed natural gas (CNG)/diesel dual fuel engine (DFE) was one of the best solutions for the above problems at present. In order to study and improve the emission performance of CNG/diesel DFE, an emission model for DFE based on radial basis function (RBF) neural network was developed which was a black-box input-output training data model not require priori knowledge. The RBF centers and the connected weights could be selected automatically according to the distribution of the training data in input-output space and the given approximating error. Studies showed that the predicted results accorded well with the experimental data over a large range of operating conditions from low load to high load. The developed emissions model based on the RBF neural network could be used to successfully predict and optimize the emissions performance of DFE. And the effect of the DFE main performance parameters, such as rotation speed, load, pilot quantity and injection timing, were also predicted by means of this model. In resumé, an emission prediction model for CNG/diesel DFE based on RBF neural network was built for analyzing the effect of the main performance parameters on the CO, NOx emissions of DFE. The predicted results agreed quite well with the traditional emissions model, which indicated that the model had certain application value, although it still has some limitations, because of its high dependence on the quantity of the experimental sample data.展开更多
In order to predict and improve the performance of natural gas/diesel dual fuel engine (DFE), a combustion rate model based on forward neural network was built to study the combustion process of the DFE. The effect ...In order to predict and improve the performance of natural gas/diesel dual fuel engine (DFE), a combustion rate model based on forward neural network was built to study the combustion process of the DFE. The effect of the operatin g parameters on combustion rate was also studied by means of this model. The stu dy showed that the predicted results were good agreement with the experimental d a ta. It was proved that the developed combustion rate model could be used to succ essfully predict and optimize the combustion process of dual fuel engine.展开更多
The present work used a methane-air mixture chemical kinetics scheme consisting of 119 elementary reaction steps and 41 chemical species to develop a simplified combustion model for prediction of the knock in dual fue...The present work used a methane-air mixture chemical kinetics scheme consisting of 119 elementary reaction steps and 41 chemical species to develop a simplified combustion model for prediction of the knock in dual fuel engines. Calculated values by the model for natural gas operation showed good agreement with corresponding experimental values over a broad range of operating conditions.展开更多
The rational design and optimization of noble-metal-free semiconductor photocatalysts aim to increase the number of active sites and accelerate the separation and transfer of charges,thereby achieving high-performance...The rational design and optimization of noble-metal-free semiconductor photocatalysts aim to increase the number of active sites and accelerate the separation and transfer of charges,thereby achieving high-performance hydrogen evolution reactions(HER).In this study,we innovatively designed an S-scheme heterojunction catalyst composed of CdS nanoparticles rich in cationic Cd vacancies(VCCS)and ZnWO4nanorods rich in anionic O vacancies(VOZWO)that regulate the surface electronic states of the catalyst through dual vacancies engineering.Specifically,the introduction of vacancy engineering effectively adjusted the energy level structure of the catalyst,achieving bandgap narrowing,enhancing light absorption capacity,providing hole trapping sites,and creating more active sites.As expected,the optimized VOZWO@VCCS heterojunction exhibited exceptional photocatalytic H_(2)production rates of 11.55 mmol g^(-1)h^(-1)in the absence of noble-metal cocatalysts,which are approximately 462 times and4 times higher than those of pure VOZWO(0.025 mmol g^(-1)h^(-1))and VCCS(2.89 mmol g^(-1)h^(-1)),respectively.In-depth characterization tests and density functional theory(DFT)calculations revealed that the introduction of vacancies significantly reduced the bandgap,improved the transfer efficiency of photoinduced carriers,and validated the charge transfer mechanism of the S-scheme heterojunction.展开更多
Ammonia,as a zero-carbon fuel,has great potential for meeting decarbonization targets in the internal combustion engine sector.This paper summarizes recent studies in which ammonia is used as a fuel for compressionign...Ammonia,as a zero-carbon fuel,has great potential for meeting decarbonization targets in the internal combustion engine sector.This paper summarizes recent studies in which ammonia is used as a fuel for compressionignition engines.Due to its low combustion reactivity,ammonia must be used in conjunction with a high reactivity fuel,such as diesel,to ensure stable engine operation.Currently,two main approaches are used to supply ammonia to the engine combustion chamber:ammonia port injection and in-cylinder direct injection.In the two routes,ammonia-diesel engines commonly face challenges such as low ammonia energy rate(AER),limited thermal efficiency,and high emissions of nitrogen-containing pollutants,especially under high ammonia substitution conditions.To address these challenges,this study reviews combustion technologies capable of achieving relatively high AER,such as premixed charge compression ignition(PCCI)and reaction-controlled compression ignition(RCCI),and analyzes their impact on combustion and emissions characteristics.This paper also examines combustion technologies under ultra-high AER conditions and finds that technologies such as diesel pilot injection and ammonia-diesel stratified injection can support stable engine operation.This review provides insights into current progress,remaining challenges,and future directions in ammonia-diesel engine combustion technologies.展开更多
基金the foundation of Guangdong Engineering Technology Research Center for Hydrogen Energy and Fuel Cells,the Guangdong Provincial Department of Education Innovation Project(No.2022KQNCX056)the Guangdong Basic and Applied Basic Research Foundation(Nos.2022A1515110354 and 2021A1515110582)。
文摘Self-supported nanoarrays have emerged as a promising alternative electrocatalyst for alkaline H_(2)O splitting,owing to their accessible active sites and strongly coupled interfaces with current collectors for improved mass transfer and stability.Herein,self-supported crystalline/amorphous NiO/Ni(OH)_(2)nanosheet arrays on nickel foam(NF)are fabricated via an in-situ dissolution-deposition hydrothermal growing of Ni(OH)_(2)nanosheets without additional metal sources assisted by a common Lewis base,EDTA,followed by a rapid calcination at 300℃in air.The as-prepared EDTA-NF-12 h exhibits high OER and HER performance under alkaline conditions,requiring 235 mV and 158 mV,respectively,to reach 10 mA cm^(-2),and the decent performance can be maintained for 24 h without obvious degradation.The dual interfaces,i.e.,the dense crystalline/amorphous interfaces within the NiO/Ni(OH)_(2)nanosheet arrays,as well as the intimate interfaces between nanoarrays and NF,both serve as reaction active sites,facilitate electron transfer,and endow the catalyst with high activity and stability.Furthermore,by applying EDTA-Ni^(2+)and other Lewis bases with varying basicities instead of EDTA,the interfaces with the NF substrate are found to promote the formation of crystalline/amorphous interfaces within the nanosheets.This study offers appealing opportunities for tailoring the electrocatalytic performance of self-supported electrodes via dual interface engineering.
文摘Achieving simultaneous reduction of NOx,CO and unburned hydrocarbon(UHC) emissions without compromising engine performance at part loads is the current focus of dual fuel engine research.The present work focuses on an experimental investigation conducted on a dual fuel(diesel-natural gas) engine to examine the simultaneous effect of inlet air pre-heating and exhaust gas recirculation(EGR) ratio on performance and emission characteristics at part loads.The use of EGR at high levels seems to be unable to improve the engine performance at part loads.However,it is shown that EGR combined with pre-heating of inlet air can slightly increase thermal efficiency,resulting in reduced levels of both unburned hydrocarbon and NOx emissions.CO and UHC emissions are reduced by 24% and 31%,respectively,The NOx emissions decrease by 21% because of the lower combustion temperature due to the much inert gas brought by EGR and decreased oxygen concentration in the cylinder.
文摘Great efforts have been made to resolve the serious environmental pollution and inevitable declining of energy resources. A review of Chinese fuel reserves and engine technology showed that compressed natural gas (CNG)/diesel dual fuel engine (DFE) was one of the best solutions for the above problems at present. In order to study and improve the emission performance of CNG/diesel DFE, an emission model for DFE based on radial basis function (RBF) neural network was developed which was a black-box input-output training data model not require priori knowledge. The RBF centers and the connected weights could be selected automatically according to the distribution of the training data in input-output space and the given approximating error. Studies showed that the predicted results accorded well with the experimental data over a large range of operating conditions from low load to high load. The developed emissions model based on the RBF neural network could be used to successfully predict and optimize the emissions performance of DFE. And the effect of the DFE main performance parameters, such as rotation speed, load, pilot quantity and injection timing, were also predicted by means of this model. In resumé, an emission prediction model for CNG/diesel DFE based on RBF neural network was built for analyzing the effect of the main performance parameters on the CO, NOx emissions of DFE. The predicted results agreed quite well with the traditional emissions model, which indicated that the model had certain application value, although it still has some limitations, because of its high dependence on the quantity of the experimental sample data.
文摘In order to predict and improve the performance of natural gas/diesel dual fuel engine (DFE), a combustion rate model based on forward neural network was built to study the combustion process of the DFE. The effect of the operatin g parameters on combustion rate was also studied by means of this model. The stu dy showed that the predicted results were good agreement with the experimental d a ta. It was proved that the developed combustion rate model could be used to succ essfully predict and optimize the combustion process of dual fuel engine.
文摘The present work used a methane-air mixture chemical kinetics scheme consisting of 119 elementary reaction steps and 41 chemical species to develop a simplified combustion model for prediction of the knock in dual fuel engines. Calculated values by the model for natural gas operation showed good agreement with corresponding experimental values over a broad range of operating conditions.
基金supported by the National Natural Science Foundation of China(22271106,52073286)the Natural Science Foundation of Fujian Province(2006 L2005)。
文摘The rational design and optimization of noble-metal-free semiconductor photocatalysts aim to increase the number of active sites and accelerate the separation and transfer of charges,thereby achieving high-performance hydrogen evolution reactions(HER).In this study,we innovatively designed an S-scheme heterojunction catalyst composed of CdS nanoparticles rich in cationic Cd vacancies(VCCS)and ZnWO4nanorods rich in anionic O vacancies(VOZWO)that regulate the surface electronic states of the catalyst through dual vacancies engineering.Specifically,the introduction of vacancy engineering effectively adjusted the energy level structure of the catalyst,achieving bandgap narrowing,enhancing light absorption capacity,providing hole trapping sites,and creating more active sites.As expected,the optimized VOZWO@VCCS heterojunction exhibited exceptional photocatalytic H_(2)production rates of 11.55 mmol g^(-1)h^(-1)in the absence of noble-metal cocatalysts,which are approximately 462 times and4 times higher than those of pure VOZWO(0.025 mmol g^(-1)h^(-1))and VCCS(2.89 mmol g^(-1)h^(-1)),respectively.In-depth characterization tests and density functional theory(DFT)calculations revealed that the introduction of vacancies significantly reduced the bandgap,improved the transfer efficiency of photoinduced carriers,and validated the charge transfer mechanism of the S-scheme heterojunction.
基金supported by the National Key Research and Development Program of China(Grant No.2022YFE0209000)Science and Technology Commission of Shanghai Municipality,China(Grant Nos.22170712600,24120742400,and 24120750400)Science and Technology Revitalization Mongolia Action Plan of Shanghai Jiao Tong University and Shanghai Jiao Tong University-Wuxi Carbon-Neutrality Power Technology Research Institute.
文摘Ammonia,as a zero-carbon fuel,has great potential for meeting decarbonization targets in the internal combustion engine sector.This paper summarizes recent studies in which ammonia is used as a fuel for compressionignition engines.Due to its low combustion reactivity,ammonia must be used in conjunction with a high reactivity fuel,such as diesel,to ensure stable engine operation.Currently,two main approaches are used to supply ammonia to the engine combustion chamber:ammonia port injection and in-cylinder direct injection.In the two routes,ammonia-diesel engines commonly face challenges such as low ammonia energy rate(AER),limited thermal efficiency,and high emissions of nitrogen-containing pollutants,especially under high ammonia substitution conditions.To address these challenges,this study reviews combustion technologies capable of achieving relatively high AER,such as premixed charge compression ignition(PCCI)and reaction-controlled compression ignition(RCCI),and analyzes their impact on combustion and emissions characteristics.This paper also examines combustion technologies under ultra-high AER conditions and finds that technologies such as diesel pilot injection and ammonia-diesel stratified injection can support stable engine operation.This review provides insights into current progress,remaining challenges,and future directions in ammonia-diesel engine combustion technologies.
