Photothermal catalytic methane dry reforming(DRM)technology can convert greenhouse gases(i.e.CH_(4)and CO_(2))into syngas(i.e.H_(2)and CO),providing more opportunities for reducing the greenhouse effect and achieving ...Photothermal catalytic methane dry reforming(DRM)technology can convert greenhouse gases(i.e.CH_(4)and CO_(2))into syngas(i.e.H_(2)and CO),providing more opportunities for reducing the greenhouse effect and achieving carbon neutrality.In the DRM field,Ni-based catalysts attract wide attention due to their low cost and high activity.However,the carbon deposition over Ni-based catalysts always leads to rapid deactivation,which is still a main challenge.To improve the long-term stability of Ni-based catalysts,this work proposes a carbon-atom-diffusion strategy under photothermal conditions and investigates its effect on a Zn-doped Ni-based photothermal catalyst(Ni_(3)Zn@CeO_(2)).The photothermal catalytic behavior of Ni_(3)Zn@CeO_(2)can maintain more than 70 h in DRM reaction.And the photocatalytic DRM activity of Ni_(3)Zn@CeO_(2)is 1.2 times higher than thermal catalytic activity.Density functional theory(DFT)calculation and experimental characterizations indicate that Ni_(3)Zn promotes the diffusion of carbon atoms into the Ni_(3)Zn to form the Ni_(3)ZnC0.7 phase with body-centered cubic(bcc)structure,thus inhibiting carbon deposition.Further,in-situ diffuse reflectance infrared Fourier transform(DRIFT)spectroscopy and DFT calculation prove Ni_(3)Zn@CeO_(2)benefits the CH_(4)activation and inhibits the carbon deposition during the DRM process.Through inducing carbon atoms diffusion within the Ni_(3)Zn lattice,this work provides a straightforward and feasible strategy for achieving efficient photothermal catalytic DRM and even other CH_(4)conversion implementations with long-term stability.展开更多
Thermal treatment of biomass has been attracting attention for a decade or so, especially torrefaction. However, for the past few years, wet pyrolysis, also known as hydrothermal carbonization (HTC), has been getting ...Thermal treatment of biomass has been attracting attention for a decade or so, especially torrefaction. However, for the past few years, wet pyrolysis, also known as hydrothermal carbonization (HTC), has been getting some attention. Hydrothermal carbonization is a thermal treatment of biomass in the presence of water in a temperature range of 180°C - 260°C. This method of treating biomass has some benefits which others do not, such as it can handle extremely wet biomass. However, treating biomass may not be enough for practical use. It may need to be transported and stored. Thus, this study explored the idea of pelletizing the HTC biomass. The mechanical strength of the HTC pellets was found to be 93%, whereas, higher heating value (HHV) (dry basis) was found to be 4% higher than the corresponding white pellets. The initial results with some limited parameters indicated that it would be possible to pelletize without binder. However, extensive research on energy balance and economic assessment would be necessary to achieve economic feasibility.展开更多
Absorption spectroscopy of fundamental ro-vibrational transitions in the mid-infrared region provides a powerful tool for studying the structure and dynamics of molecules in the gas phase and for sensitive and quantit...Absorption spectroscopy of fundamental ro-vibrational transitions in the mid-infrared region provides a powerful tool for studying the structure and dynamics of molecules in the gas phase and for sensitive and quantitative gas sensing.Laser frequency combs permit novel approaches to perform broadband molecular spectroscopy.Multiplex dual-comb spectroscopy without moving parts can achieve particularly high speed,sensitivity and resolution.However,achieving Doppler-limited resolution in the mid-infrared still requires overcoming instrumental challenges.Here we demonstrate a new approach based on difference-frequency generation of frequency-agile near-infrared frequency combs that are produced using electro-optic modulators.The combs have a remarkably flat intensity distribution,and their positions and line spacings can be freely selected by simply dialing a knob.Using the proposed technique,we record,in the 3-μm region,Doppler-limited absorption spectra with resolved comb lines within milliseconds,and precise molecular line parameters are retrieved.Our technique holds promise for fast and sensitive time-resolved studies of,for example,trace gases.展开更多
The paper addresses the creation of circular optical properties from a femtosecond laser light beam with a linear polarization in an achiral material(glass)under an orthogonal incidence.In this situation,all aspects o...The paper addresses the creation of circular optical properties from a femtosecond laser light beam with a linear polarization in an achiral material(glass)under an orthogonal incidence.In this situation,all aspects of the experiment are achiral and therefore should not give rise to chiral property creation.From that observation,we propose an interpretation that involves the action of a light-induced torque on the matter carrying a light-induced dielectric moment.We found that a direct current(DC)electric field could be produced in the lattice by the femtosecond laser in our conditions and that a non-collinear dielectric moment is created by a nonlinear effect between the DC electric field and the stress field due to the transformation of the material.We reveal that it is possible to break the chiral symmetry of glass using an intense,ultrashort laser light pulse.展开更多
Nowadays,biodegradable polymers such as poly(lactic acid)(PLA),poly(D,L-lactic-coglycolic acid)(PLGA)and poly(ε-caprolactone)(PCL)remain the most common biomaterials to produce drug-loaded nanoparticles(NPs).Pipemidi...Nowadays,biodegradable polymers such as poly(lactic acid)(PLA),poly(D,L-lactic-coglycolic acid)(PLGA)and poly(ε-caprolactone)(PCL)remain the most common biomaterials to produce drug-loaded nanoparticles(NPs).Pipemidic acid(PIP)is a poorly soluble antibiotic with a strong tendency to crystallize.PIP incorporation in PLA/PLGA NPs was challenging because of PIP crystals formation and burst release.As PIP had a poor affinity for the NPs,an alternative approach to encapsulation was used,consisting in coupling PIP to PCL.Thus,a PCL–PIP conjugate was successfully synthesized by an original drug-initiated polymerization in a single step without the need of catalyst.PCL–PIP was characterized by NMR,IR,SEC and mass spectrometry.PCL–PIP was used to prepare selfassembled NPs with PIP contents as high as 27%(w/w).The NPs were characterized by microscopy,DLS,NTA and TRPS.This study paves the way towards the production of NPs with high antibiotic payloads by drug-initiated polymerization.Further studies will deal with the synthesis of novel polymer–PIP conjugates with ester bonds between the drug and PCL.PIP can be considered as a model drug and the strategy developed here could be extended to other challenging antibiotics or anticancer drugs and employed to efficiently incorporate them in NPs.展开更多
文摘Photothermal catalytic methane dry reforming(DRM)technology can convert greenhouse gases(i.e.CH_(4)and CO_(2))into syngas(i.e.H_(2)and CO),providing more opportunities for reducing the greenhouse effect and achieving carbon neutrality.In the DRM field,Ni-based catalysts attract wide attention due to their low cost and high activity.However,the carbon deposition over Ni-based catalysts always leads to rapid deactivation,which is still a main challenge.To improve the long-term stability of Ni-based catalysts,this work proposes a carbon-atom-diffusion strategy under photothermal conditions and investigates its effect on a Zn-doped Ni-based photothermal catalyst(Ni_(3)Zn@CeO_(2)).The photothermal catalytic behavior of Ni_(3)Zn@CeO_(2)can maintain more than 70 h in DRM reaction.And the photocatalytic DRM activity of Ni_(3)Zn@CeO_(2)is 1.2 times higher than thermal catalytic activity.Density functional theory(DFT)calculation and experimental characterizations indicate that Ni_(3)Zn promotes the diffusion of carbon atoms into the Ni_(3)Zn to form the Ni_(3)ZnC0.7 phase with body-centered cubic(bcc)structure,thus inhibiting carbon deposition.Further,in-situ diffuse reflectance infrared Fourier transform(DRIFT)spectroscopy and DFT calculation prove Ni_(3)Zn@CeO_(2)benefits the CH_(4)activation and inhibits the carbon deposition during the DRM process.Through inducing carbon atoms diffusion within the Ni_(3)Zn lattice,this work provides a straightforward and feasible strategy for achieving efficient photothermal catalytic DRM and even other CH_(4)conversion implementations with long-term stability.
文摘Thermal treatment of biomass has been attracting attention for a decade or so, especially torrefaction. However, for the past few years, wet pyrolysis, also known as hydrothermal carbonization (HTC), has been getting some attention. Hydrothermal carbonization is a thermal treatment of biomass in the presence of water in a temperature range of 180°C - 260°C. This method of treating biomass has some benefits which others do not, such as it can handle extremely wet biomass. However, treating biomass may not be enough for practical use. It may need to be transported and stored. Thus, this study explored the idea of pelletizing the HTC biomass. The mechanical strength of the HTC pellets was found to be 93%, whereas, higher heating value (HHV) (dry basis) was found to be 4% higher than the corresponding white pellets. The initial results with some limited parameters indicated that it would be possible to pelletize without binder. However, extensive research on energy balance and economic assessment would be necessary to achieve economic feasibility.
基金European Research Council(Advanced Investigator Grant 267854)Munich Center for Advanced Photonics Max Planck Foundation+1 种基金IXCORE Fondation pour la RecherchePARI PHOTCOM Région Bourgogne,Labex ACTION program(Contract No.ANR-11-LABX-0001-01).
文摘Absorption spectroscopy of fundamental ro-vibrational transitions in the mid-infrared region provides a powerful tool for studying the structure and dynamics of molecules in the gas phase and for sensitive and quantitative gas sensing.Laser frequency combs permit novel approaches to perform broadband molecular spectroscopy.Multiplex dual-comb spectroscopy without moving parts can achieve particularly high speed,sensitivity and resolution.However,achieving Doppler-limited resolution in the mid-infrared still requires overcoming instrumental challenges.Here we demonstrate a new approach based on difference-frequency generation of frequency-agile near-infrared frequency combs that are produced using electro-optic modulators.The combs have a remarkably flat intensity distribution,and their positions and line spacings can be freely selected by simply dialing a knob.Using the proposed technique,we record,in the 3-μm region,Doppler-limited absorption spectra with resolved comb lines within milliseconds,and precise molecular line parameters are retrieved.Our technique holds promise for fast and sensitive time-resolved studies of,for example,trace gases.
基金the support of FP7-PEOPLE-IRSES e-FLAG 247635 from the Agence Nationale pour la Recherche(ANR-09-BLAN-0172-01).
文摘The paper addresses the creation of circular optical properties from a femtosecond laser light beam with a linear polarization in an achiral material(glass)under an orthogonal incidence.In this situation,all aspects of the experiment are achiral and therefore should not give rise to chiral property creation.From that observation,we propose an interpretation that involves the action of a light-induced torque on the matter carrying a light-induced dielectric moment.We found that a direct current(DC)electric field could be produced in the lattice by the femtosecond laser in our conditions and that a non-collinear dielectric moment is created by a nonlinear effect between the DC electric field and the stress field due to the transformation of the material.We reveal that it is possible to break the chiral symmetry of glass using an intense,ultrashort laser light pulse.
基金Financial support for this work was provided by the European Community through the Marie Curie ITN CycloN Hit Grant no.608407supported by a public grant overseen by the French National Research Agency(ANR)as part of the"Investissements d'Avenir"program(Labex Nano Saclay,reference:ANR-10-LABX-0035)by the ANR-14-CE08-0017 grant
文摘Nowadays,biodegradable polymers such as poly(lactic acid)(PLA),poly(D,L-lactic-coglycolic acid)(PLGA)and poly(ε-caprolactone)(PCL)remain the most common biomaterials to produce drug-loaded nanoparticles(NPs).Pipemidic acid(PIP)is a poorly soluble antibiotic with a strong tendency to crystallize.PIP incorporation in PLA/PLGA NPs was challenging because of PIP crystals formation and burst release.As PIP had a poor affinity for the NPs,an alternative approach to encapsulation was used,consisting in coupling PIP to PCL.Thus,a PCL–PIP conjugate was successfully synthesized by an original drug-initiated polymerization in a single step without the need of catalyst.PCL–PIP was characterized by NMR,IR,SEC and mass spectrometry.PCL–PIP was used to prepare selfassembled NPs with PIP contents as high as 27%(w/w).The NPs were characterized by microscopy,DLS,NTA and TRPS.This study paves the way towards the production of NPs with high antibiotic payloads by drug-initiated polymerization.Further studies will deal with the synthesis of novel polymer–PIP conjugates with ester bonds between the drug and PCL.PIP can be considered as a model drug and the strategy developed here could be extended to other challenging antibiotics or anticancer drugs and employed to efficiently incorporate them in NPs.
