Heterojunction design in a two-dimensional(2D)fashion has been deemed beneficial for improving the photocatalytic activity of g-C_(3)N_(4)because of the promoted interfacial charge transfer,yet still facing challenges...Heterojunction design in a two-dimensional(2D)fashion has been deemed beneficial for improving the photocatalytic activity of g-C_(3)N_(4)because of the promoted interfacial charge transfer,yet still facing challenges.Herein,we construct a novel 2D/2D Cu_(3)P nanosheet/P-doped g-C_(3)N_(4)(PCN)nanosheet heterojunction photocatalyst(PCN/Cu_(3)P)through a simple in-situ phosphorization treatment of 2D/2D CuS/g-C_(3)N_(4)composite for photocatalytic H2 evolution.We demonstrate that the 2D lamellar structure of both CuS and g-C_(3)N_(4)could be well reserved in the phosphorization process,while CuS and g-C_(3)N_(4)in-situ transformed into Cu_(3)P and PCN,respectively,leading to the formation of PCN/Cu_(3)P tight 2D/2D heterojunction.Owing to the large contact area provided by intimate face-to-face 2D/2D structure,the PCN/Cu_(3)P photocatalyst exhibits significantly enhanced charge separation efficiency,thus achieving a boosted visible-light-driven photocatalytic behavior.The highest rate for H2 evolution reaches 5.12 umol·h^(-1),nearly 24 times and 368 times higher than that of pristine PCN and g-C_(3)N_(4),respectively.This work represents an excellent example in elaborately con-structing g-C_(3)N_(4)-based 2D/2D heterostructure and could be extended to other photocatalyst/co-catalyst system.展开更多
Noble-metal nanocrystals enclosed by high-index facets are of growing interest due to their enhanced catalytic performance in a variety of reactions.Herein,we report the deterministic synthesis of Pd nanocrystals enca...Noble-metal nanocrystals enclosed by high-index facets are of growing interest due to their enhanced catalytic performance in a variety of reactions.Herein,we report the deterministic synthesis of Pd nanocrystals encased by high-index facets by controlling the rate of deposition(V_(deposition))relative to that of surface diffusion(V_(diffusion)).For octahedral seeds with truncated corners,a reduction rate(and thus deposition rate)faster than that of surface diffusion(i.e.,V_(deposition)/V_(diffusion)>1)led to the formation of concave trisoctahedra(TOH)with high-index facets.When the reduction was slowed down,in contrast,surface diffusion dominated the growth pathway.In the case of V_(deposition)/V_(diffusion)≈1,truncated octahedra with enlarged sizes were produced.When the reduction rate was between these two extremes,we obtained concave tetrahexahedra(THH)without or with truncation.Similar growth patterns were also observed for the cuboctahedral seeds.When the Pd octahedra,concave TOH,and concave THH were tested for electrocatalyzing the formic acid oxidation(FAO)reaction,those with high-index facets were advantageous over the conventional Pd octahedra enclosed by{111}facets.This work not only contributes to the understanding of surface diffusion and its role in nanocrystal growth but also offers a general protocol for the synthesis of nanocrystals enclosed by high-index facets.展开更多
Main observation and conclusion Important progress has been made in the development of energetic molecules with high performance by computer-aided molecular design in recent years,but structural novelty of organic sca...Main observation and conclusion Important progress has been made in the development of energetic molecules with high performance by computer-aided molecular design in recent years,but structural novelty of organic scaffolds is insufficient.In this work,we propose an intra-ring bridging strategy inspired by the known energetic nitramines to design novel polycyclic and cage energetic molecules.More than 100 energetic structures were designed by introducing the C—C bridges and increasing the ring size.The synthesis difficulty is considered besides the two most concerned properties of EMs,energy and safety.After a comprehensive estimation,a symmetric cage molecule labeled as 8U-30 was finally selected because of its relatively high detonation performance,and comparable impact sensitivity as well as synthetic accessibility with CL-20.Hopefully,the proposed strategy could be utilized in further molecular design to gain various scaffolds,especially cage structures,for different demands.展开更多
基金We acknowledge the support from the National Natural Science Foundation of China(Nos.51876173 and 52142604)the Natural Science Foundation of Jiangsu Province(No.BK20190054)+2 种基金the Suzhou Science and Technology Program(SYG202101)Fok Ying-Tung Education Foundation(No.171048)the China Fundamental Research Funds for the Central Universities.
文摘Heterojunction design in a two-dimensional(2D)fashion has been deemed beneficial for improving the photocatalytic activity of g-C_(3)N_(4)because of the promoted interfacial charge transfer,yet still facing challenges.Herein,we construct a novel 2D/2D Cu_(3)P nanosheet/P-doped g-C_(3)N_(4)(PCN)nanosheet heterojunction photocatalyst(PCN/Cu_(3)P)through a simple in-situ phosphorization treatment of 2D/2D CuS/g-C_(3)N_(4)composite for photocatalytic H2 evolution.We demonstrate that the 2D lamellar structure of both CuS and g-C_(3)N_(4)could be well reserved in the phosphorization process,while CuS and g-C_(3)N_(4)in-situ transformed into Cu_(3)P and PCN,respectively,leading to the formation of PCN/Cu_(3)P tight 2D/2D heterojunction.Owing to the large contact area provided by intimate face-to-face 2D/2D structure,the PCN/Cu_(3)P photocatalyst exhibits significantly enhanced charge separation efficiency,thus achieving a boosted visible-light-driven photocatalytic behavior.The highest rate for H2 evolution reaches 5.12 umol·h^(-1),nearly 24 times and 368 times higher than that of pristine PCN and g-C_(3)N_(4),respectively.This work represents an excellent example in elaborately con-structing g-C_(3)N_(4)-based 2D/2D heterostructure and could be extended to other photocatalyst/co-catalyst system.
基金the NSF(CBET-2219546)and startup funds from the Georgia Institute of Technology.
文摘Noble-metal nanocrystals enclosed by high-index facets are of growing interest due to their enhanced catalytic performance in a variety of reactions.Herein,we report the deterministic synthesis of Pd nanocrystals encased by high-index facets by controlling the rate of deposition(V_(deposition))relative to that of surface diffusion(V_(diffusion)).For octahedral seeds with truncated corners,a reduction rate(and thus deposition rate)faster than that of surface diffusion(i.e.,V_(deposition)/V_(diffusion)>1)led to the formation of concave trisoctahedra(TOH)with high-index facets.When the reduction was slowed down,in contrast,surface diffusion dominated the growth pathway.In the case of V_(deposition)/V_(diffusion)≈1,truncated octahedra with enlarged sizes were produced.When the reduction rate was between these two extremes,we obtained concave tetrahexahedra(THH)without or with truncation.Similar growth patterns were also observed for the cuboctahedral seeds.When the Pd octahedra,concave TOH,and concave THH were tested for electrocatalyzing the formic acid oxidation(FAO)reaction,those with high-index facets were advantageous over the conventional Pd octahedra enclosed by{111}facets.This work not only contributes to the understanding of surface diffusion and its role in nanocrystal growth but also offers a general protocol for the synthesis of nanocrystals enclosed by high-index facets.
基金support from the National Natural Science Foundation of China(Nos.21875184,21978311)the Youth Talent of Shaanxi"TeZhi"Programproject sponsored by Xi’an Modern Chemistry Research Institute(WDZCKYXM20190101).
文摘Main observation and conclusion Important progress has been made in the development of energetic molecules with high performance by computer-aided molecular design in recent years,but structural novelty of organic scaffolds is insufficient.In this work,we propose an intra-ring bridging strategy inspired by the known energetic nitramines to design novel polycyclic and cage energetic molecules.More than 100 energetic structures were designed by introducing the C—C bridges and increasing the ring size.The synthesis difficulty is considered besides the two most concerned properties of EMs,energy and safety.After a comprehensive estimation,a symmetric cage molecule labeled as 8U-30 was finally selected because of its relatively high detonation performance,and comparable impact sensitivity as well as synthetic accessibility with CL-20.Hopefully,the proposed strategy could be utilized in further molecular design to gain various scaffolds,especially cage structures,for different demands.
