The intrinsic symmetrical electron distribution in crystalline metal sulfides usually causes an improper electronic configuration between catalytic S atoms and H intermediates(H_(ad))to form strong S-H_(ad) bonds,resu...The intrinsic symmetrical electron distribution in crystalline metal sulfides usually causes an improper electronic configuration between catalytic S atoms and H intermediates(H_(ad))to form strong S-H_(ad) bonds,resulting in a low photocatalytic H_(2) evolution activity.Herein,a cobalt-induced asymmetric electronic distribution is justified as an effective strategy to optimize the electronic configuration of catalytic S sites in NiCoS cocatalysts for highly active photocatalytic H_(2) evolution.To this end,Co atoms are uniformly incorporated in NiS nanoparticles to fabricate homogeneous NiCoS cocatalyst on TiO_(2) surface by a facile photosynthesis strategy.It is revealed that the incorporated Co atoms break the electron distribution symmetry in NiS,thus essentially increasing the electron density of S atoms to form active electron-enriched S^(2+δ)–sites.The electron-enriched S^(2+δ)–sites could interact with Had via an increased antibonding orbital occupancy,which weakens S–Had bonds for efficient H_(ad) adsorption and desorption,endowing the NiCoS cocatalysts with a highly active H_(2) evolution process.Consequently,the optimized NiCoS/TiO_(2)(1:2)photocatalyst displays the highest H_(2) production performance,outperforming the NiS/TiO_(2) and CoS/TiO_(2) samples by factors of 2.1 and 2.5,respectively.This work provides novel insights on breaking electron distribution symmetry to optimize catalytic efficiency of active sites.展开更多
BA_(2)(MA)_(n-1)Pb_nI_(3n+1)series low-dimensional(2D)perovskites have been widely investigated for their re markable environmental stability,but still suffer the poor light absorption and disordered phase distri buti...BA_(2)(MA)_(n-1)Pb_nI_(3n+1)series low-dimensional(2D)perovskites have been widely investigated for their re markable environmental stability,but still suffer the poor light absorption and disordered phase distri bution,hindering their practical applications.In this work,we combine the introduction of FA and the addition of PbCl_(2)to optimize the film quality,strengthen the light absorption,regulate internal phase distribution,and promote carrier transport inside 2D perovskite films.The incorporation of FA promote sufficient light absorption and improve the film crystallinity.Furthermore,the addition of Pb Cl_(2)elimi nates the low n phase(n=1)and suppresses the forming of the low n phase of n=2,enhancing the film conductivity and diminishing carrier recombination.The synergistic of A-site cation engineering and phase manipulation achieves a high efficiency of 16.48%.Importantly,the synergistic prepared perovskite film does not show any changes after 60 days in the air with an average humidity of 57%±3%,and the corresponding solar cell maintains 85%of the original efficiency after more than 800 h,demonstrating remarkable environmental stability.The results indicate that the synergistic of A-site cation engineering and phase manipulation is promising for producing superior efficiency,along with satisfying humidity stability.展开更多
This work presents a novel design of Ka-band(33 GHz)filtering packaging antenna(FPA)that features broadband and great filtering response,and is based on glass packaging material and through-glass via(TGV)technologies....This work presents a novel design of Ka-band(33 GHz)filtering packaging antenna(FPA)that features broadband and great filtering response,and is based on glass packaging material and through-glass via(TGV)technologies.Compared to traditional packaging materials(printed circuit board,low temperature co-fired ceramic,Si,etc.),TGVs are more suitable for miniaturization(millimeter-wave three-dimensional(3D)packaging devices)and have superior microwave performance.Glass substrate can realize 3D high-density interconnection through bonding technology,while the coefficient of thermal expansion(CTE)matches that of silicon.Furthermore,the stacking of glass substrate enables high-density interconnections and is compatible with micro-electro-mechanical system technology.The proposed antenna radiation patch is composed of a patch antenna and a bandpass filter(BPF)whose reflection coefficients are almost complementary.The BPF unit has three pairs ofλg/4 slots(defect microstrip structure,DMS)and twoλg/2 U-shaped slots(defect ground structure,DGS).The proposed antenna achieves large bandwidth and high radiation efficiency,which may be related to the stacking of glass substrate and TGV feed.In addition,the introduction of four radiation nulls can effectively improve the suppression level in the stopband.To demonstrate the performance of the proposed design,a 33-GHz broadband filtering antenna is optimized,debugged,and measured.The antenna could achieve|S11|<-10 dB in 29.4‒36.4 GHz,and yield an impedance matching bandwidth up to 21.2%,with the stopband suppression level at higher than 16.5 dB.The measurement results of the proposed antenna are a realized gain of~6.5 dBi and radiation efficiency of~89%.展开更多
文摘The intrinsic symmetrical electron distribution in crystalline metal sulfides usually causes an improper electronic configuration between catalytic S atoms and H intermediates(H_(ad))to form strong S-H_(ad) bonds,resulting in a low photocatalytic H_(2) evolution activity.Herein,a cobalt-induced asymmetric electronic distribution is justified as an effective strategy to optimize the electronic configuration of catalytic S sites in NiCoS cocatalysts for highly active photocatalytic H_(2) evolution.To this end,Co atoms are uniformly incorporated in NiS nanoparticles to fabricate homogeneous NiCoS cocatalyst on TiO_(2) surface by a facile photosynthesis strategy.It is revealed that the incorporated Co atoms break the electron distribution symmetry in NiS,thus essentially increasing the electron density of S atoms to form active electron-enriched S^(2+δ)–sites.The electron-enriched S^(2+δ)–sites could interact with Had via an increased antibonding orbital occupancy,which weakens S–Had bonds for efficient H_(ad) adsorption and desorption,endowing the NiCoS cocatalysts with a highly active H_(2) evolution process.Consequently,the optimized NiCoS/TiO_(2)(1:2)photocatalyst displays the highest H_(2) production performance,outperforming the NiS/TiO_(2) and CoS/TiO_(2) samples by factors of 2.1 and 2.5,respectively.This work provides novel insights on breaking electron distribution symmetry to optimize catalytic efficiency of active sites.
基金supported by the Chengdu Science and Technology Program(No.2021GH0200032HZ)Sichuan Engineering Technology Research Center of Basalt Fiber Composites Development and Application(No.2022SCXWYXWFC006)Natural Science Foundation of Sichuan Province(No.2022NSFSC0356)。
文摘BA_(2)(MA)_(n-1)Pb_nI_(3n+1)series low-dimensional(2D)perovskites have been widely investigated for their re markable environmental stability,but still suffer the poor light absorption and disordered phase distri bution,hindering their practical applications.In this work,we combine the introduction of FA and the addition of PbCl_(2)to optimize the film quality,strengthen the light absorption,regulate internal phase distribution,and promote carrier transport inside 2D perovskite films.The incorporation of FA promote sufficient light absorption and improve the film crystallinity.Furthermore,the addition of Pb Cl_(2)elimi nates the low n phase(n=1)and suppresses the forming of the low n phase of n=2,enhancing the film conductivity and diminishing carrier recombination.The synergistic of A-site cation engineering and phase manipulation achieves a high efficiency of 16.48%.Importantly,the synergistic prepared perovskite film does not show any changes after 60 days in the air with an average humidity of 57%±3%,and the corresponding solar cell maintains 85%of the original efficiency after more than 800 h,demonstrating remarkable environmental stability.The results indicate that the synergistic of A-site cation engineering and phase manipulation is promising for producing superior efficiency,along with satisfying humidity stability.
基金supported by the Fundamental Research Funds for the Central Universities,China(No.ZYGX2019Z003)。
文摘This work presents a novel design of Ka-band(33 GHz)filtering packaging antenna(FPA)that features broadband and great filtering response,and is based on glass packaging material and through-glass via(TGV)technologies.Compared to traditional packaging materials(printed circuit board,low temperature co-fired ceramic,Si,etc.),TGVs are more suitable for miniaturization(millimeter-wave three-dimensional(3D)packaging devices)and have superior microwave performance.Glass substrate can realize 3D high-density interconnection through bonding technology,while the coefficient of thermal expansion(CTE)matches that of silicon.Furthermore,the stacking of glass substrate enables high-density interconnections and is compatible with micro-electro-mechanical system technology.The proposed antenna radiation patch is composed of a patch antenna and a bandpass filter(BPF)whose reflection coefficients are almost complementary.The BPF unit has three pairs ofλg/4 slots(defect microstrip structure,DMS)and twoλg/2 U-shaped slots(defect ground structure,DGS).The proposed antenna achieves large bandwidth and high radiation efficiency,which may be related to the stacking of glass substrate and TGV feed.In addition,the introduction of four radiation nulls can effectively improve the suppression level in the stopband.To demonstrate the performance of the proposed design,a 33-GHz broadband filtering antenna is optimized,debugged,and measured.The antenna could achieve|S11|<-10 dB in 29.4‒36.4 GHz,and yield an impedance matching bandwidth up to 21.2%,with the stopband suppression level at higher than 16.5 dB.The measurement results of the proposed antenna are a realized gain of~6.5 dBi and radiation efficiency of~89%.
