Photocatalytic hydrogen evolution coupled with organic oxidation holds great promise for converting solar energy into high-valueadded chemicals,but it is hampered by sluggish charge dynamics and limited redox potentia...Photocatalytic hydrogen evolution coupled with organic oxidation holds great promise for converting solar energy into high-valueadded chemicals,but it is hampered by sluggish charge dynamics and limited redox potential.Herein,a porous S-doped carbon nitride(S-C_(3)N_(4−y))foam assembled from ultrathin nanosheets with rich nitrogen vacancies was synthesized using a molecular selfassembly strategy.The S dopants and N vacancies synergistically adjusted the band structure,facilitating light absorption and enhancing the oxidation ability.Moreover,the ultrathin nanosheets and porous structure provided more exposed active sites and facilitated mass and charge transfer.Consequently,S-C_(3)N_(4−y) foam exhibited enhanced photocatalytic activities for synchronous hydrogen evolution(4960μmol/(h·g))and benzylamine oxidation to N-benzylidenebenzylamine(4885μmol/(h·g))with high selectivity of>99%,which were approximately 17.6 and 72.9 times higher than those of bulk CN,respectively.The photocatalytic coupling pairing reaction promotes the water splitting by consuming H2O2,thereby improving the hydrogen evolution efficiency and achieving the production of high value-added imines.This study provides an effective route for regulating the morphology and band structure of carbon nitride for synthesizing highly valuable chemicals.展开更多
The employment of spin polarization under an external magnetic field holds great potential for the improvements of photocatalytic performance.However,owing to the huge difference in dielectric properties between ferro...The employment of spin polarization under an external magnetic field holds great potential for the improvements of photocatalytic performance.However,owing to the huge difference in dielectric properties between ferromagnetic oxide and polymers,the photogenerated excitons with spin states are often limited to the ferromagnetic oxide wells,which leads to unsatisfactory activity.In this paper,a single-atom Co-doped C_(3)N_(4)photocatalyst is successfully synthesized for photocatalytic water splitting and simultaneous oxidation of benzylamine.Under a tiny external magnetic field(24.5 mT),the hydrogen production rate could reach at 3979.0μmol·g^(-1)·h^(-1),which is about 340 times that of C_(3)N_(4).Experimental results and theoretical calculations indicate that the interaction of Co d and N p orbital changes the symmetry center of C_(3)N_(4),resulting in an increase in dielectric constant and spin polarization.Moreover,magnetic fields further promote parallel electron spin,and the increased number of charges with the parallel spin-down state is likely to dissociate under the action of an external magnetic field.On the other hand,the Co-N bond provides a huge built-in electric field and active site for strengthening the charge transfer and surface reaction.This work not only deepens the understanding of spin polarization,but also enriches methods to accelerate electron-hole separation.展开更多
The electricity-driven water splitting acts as a promising pathway for renewable energy conversion and storage, yet anodic oxygen evolution reaction(OER) largely hinders its efficiency. Seeking the alternatives to OER...The electricity-driven water splitting acts as a promising pathway for renewable energy conversion and storage, yet anodic oxygen evolution reaction(OER) largely hinders its efficiency. Seeking the alternatives to OER exhibits the competitive advance to address this predicament. In this work, we show a more thermodynamically and kinetically favorable reaction, electrochemical oxidative dehydrogenation(EODH)of benzylamine to replace the conventional OER, catalyzed by a cobalt cyclotetraphosphate(Co_(2)P_(4)O_(12)) nanorods catalyst grown on nickel foam. This anodic reaction lowers the electricity input of 317 mV toward the desired current density of 100 mA/cm^(2), together with a highly selective benzonitrile product of more than 97%. More specifically, when coupling it with cathodic hydrogen evolution reaction(HER),the proposed HER||benzylamine-EODH configuration only requires a cell voltage of 1.47 V@100 mA/cm^(2),exhibiting an energy-saving up to 17% relative to conventional water splitting, as well as the near unit selectivity toward cathodic H_(2) and anodic benzonitrile products.展开更多
Primary tosylates 1a-d were converted to the corresponding amino species 3a-d. Benzylamine was proved effective for the substitution of tosylates, using acetonitrile (MeCN) as the solvent of choice and citric acid to ...Primary tosylates 1a-d were converted to the corresponding amino species 3a-d. Benzylamine was proved effective for the substitution of tosylates, using acetonitrile (MeCN) as the solvent of choice and citric acid to remove excess of the reagent from crude products 2a-d. Debenzylation was carried out at circa (ca.) atmospheric pressure of hydrogen gas in the presence of acetic acid (AcOH). The method was also demonstrated in a demo batch experiment for the synthesis of compound 3a on a 50 g scale of 1a.展开更多
基金the National Key Research and Development Program of China(No.2022YFA1503003)the National Natural Science Foundation of China(Nos.U20A20250 and 22271081)+1 种基金the Natural Science Foundation of Heilongjiang Province(No.ZD2021B003)the University Nursing Program for Young Scholars with Creative Talents in Heilongjiang Province(No.UNPYSCT-2020004).
文摘Photocatalytic hydrogen evolution coupled with organic oxidation holds great promise for converting solar energy into high-valueadded chemicals,but it is hampered by sluggish charge dynamics and limited redox potential.Herein,a porous S-doped carbon nitride(S-C_(3)N_(4−y))foam assembled from ultrathin nanosheets with rich nitrogen vacancies was synthesized using a molecular selfassembly strategy.The S dopants and N vacancies synergistically adjusted the band structure,facilitating light absorption and enhancing the oxidation ability.Moreover,the ultrathin nanosheets and porous structure provided more exposed active sites and facilitated mass and charge transfer.Consequently,S-C_(3)N_(4−y) foam exhibited enhanced photocatalytic activities for synchronous hydrogen evolution(4960μmol/(h·g))and benzylamine oxidation to N-benzylidenebenzylamine(4885μmol/(h·g))with high selectivity of>99%,which were approximately 17.6 and 72.9 times higher than those of bulk CN,respectively.The photocatalytic coupling pairing reaction promotes the water splitting by consuming H2O2,thereby improving the hydrogen evolution efficiency and achieving the production of high value-added imines.This study provides an effective route for regulating the morphology and band structure of carbon nitride for synthesizing highly valuable chemicals.
基金This project was financially supported by the Guizhou Provincial Science and Technology Foundation(No.ZK2021069)the National Natural Science Foundation of China(No.22268015)+1 种基金the Young Science and Technology Talents Development Project of Education Department in Guizhou Province(No.KY2022144)the Innovation Group Project of Education Department in Guizhou Province(NO.2021010).
文摘The employment of spin polarization under an external magnetic field holds great potential for the improvements of photocatalytic performance.However,owing to the huge difference in dielectric properties between ferromagnetic oxide and polymers,the photogenerated excitons with spin states are often limited to the ferromagnetic oxide wells,which leads to unsatisfactory activity.In this paper,a single-atom Co-doped C_(3)N_(4)photocatalyst is successfully synthesized for photocatalytic water splitting and simultaneous oxidation of benzylamine.Under a tiny external magnetic field(24.5 mT),the hydrogen production rate could reach at 3979.0μmol·g^(-1)·h^(-1),which is about 340 times that of C_(3)N_(4).Experimental results and theoretical calculations indicate that the interaction of Co d and N p orbital changes the symmetry center of C_(3)N_(4),resulting in an increase in dielectric constant and spin polarization.Moreover,magnetic fields further promote parallel electron spin,and the increased number of charges with the parallel spin-down state is likely to dissociate under the action of an external magnetic field.On the other hand,the Co-N bond provides a huge built-in electric field and active site for strengthening the charge transfer and surface reaction.This work not only deepens the understanding of spin polarization,but also enriches methods to accelerate electron-hole separation.
基金financially supported in part by National Key R&D Program of China(No.2020YFA0406103)National Natural Science Foundation of China(NSFC,Nos.21725102,22122506,22075267,U1832156,91961106,51902311)+5 种基金DNL Cooperation Fund,CAS(No.DNL201922)Strategic Priority Research Program of the CAS(No.XDPB14)Anhui Provincial Natural Science Foundation(No.2008085J05)Youth Innovation Promotion Association of CAS(No.2019444)Open Funding Project of National Key Laboratory of Human Factors Engineering(No.SYFD062010K)support from USTC Center for Micro-and Nanoscale Research and Fabrication。
文摘The electricity-driven water splitting acts as a promising pathway for renewable energy conversion and storage, yet anodic oxygen evolution reaction(OER) largely hinders its efficiency. Seeking the alternatives to OER exhibits the competitive advance to address this predicament. In this work, we show a more thermodynamically and kinetically favorable reaction, electrochemical oxidative dehydrogenation(EODH)of benzylamine to replace the conventional OER, catalyzed by a cobalt cyclotetraphosphate(Co_(2)P_(4)O_(12)) nanorods catalyst grown on nickel foam. This anodic reaction lowers the electricity input of 317 mV toward the desired current density of 100 mA/cm^(2), together with a highly selective benzonitrile product of more than 97%. More specifically, when coupling it with cathodic hydrogen evolution reaction(HER),the proposed HER||benzylamine-EODH configuration only requires a cell voltage of 1.47 V@100 mA/cm^(2),exhibiting an energy-saving up to 17% relative to conventional water splitting, as well as the near unit selectivity toward cathodic H_(2) and anodic benzonitrile products.
文摘Primary tosylates 1a-d were converted to the corresponding amino species 3a-d. Benzylamine was proved effective for the substitution of tosylates, using acetonitrile (MeCN) as the solvent of choice and citric acid to remove excess of the reagent from crude products 2a-d. Debenzylation was carried out at circa (ca.) atmospheric pressure of hydrogen gas in the presence of acetic acid (AcOH). The method was also demonstrated in a demo batch experiment for the synthesis of compound 3a on a 50 g scale of 1a.
