The reasonable employment of cocatalyst in photocatalysis can effectively promote the photocatalytic H_(2)production activity.In this study,carbon hollow spheres(C),as a good conductive nonmetallic material,have been ...The reasonable employment of cocatalyst in photocatalysis can effectively promote the photocatalytic H_(2)production activity.In this study,carbon hollow spheres(C),as a good conductive nonmetallic material,have been utilized as a novel cocatalyst and a matrix for loading the Cu-doped-TiO_(2)nanoparticles by a successive hydrother-mal method and metal molten salt method.The Cu-doped-TiO_(2)nanoparticles were tightly anchored on the surface of carbon hollow sphere to form a zero-dimensional/three dimensional(0D/3D)Cu-doped-TiO2/C heterojunction.The optimal Cu-doped-TiO_(2)/C heterojunction demon-strated greatly enhanced photocatalytic H_(2) generation activity(14.4 mmol·g^(-1)·h^(-1))compared with TiO_(2)(0.33 mmol·g^(-1)·h^(-1))and TiO_(2)/C(0.7 mmol·g^(-1)·h^(-1)).The performance improvement was mainly due to the syner-gistic effect of carbon hollow sphere cocatalyst and Cu-doping,the Cu-doping in TiO_(2)nanoparticles can minimize charge recombination and enhance the available photoex-cited electrons,while the 3D carbon hollow spheres can act as electron traps to accelerate the charge separation and offer abundant active sites for solar water splitting reaction.展开更多
Hierarchically porous nitrogen-doped carbon(HPNC) with interconnected micro-,meso-,and macropores was generated from KOH and urea etching as a carbon scaffold to infuse Se.In this structure,micropores confine Se as si...Hierarchically porous nitrogen-doped carbon(HPNC) with interconnected micro-,meso-,and macropores was generated from KOH and urea etching as a carbon scaffold to infuse Se.In this structure,micropores confine Se as single-chain molecules,preventing the generation of higher-order polyselenides,the mesopores provide effective pathways for electrolyte diffusion and ion transport and offer sufficient void space to accommodate the volume change of Se upon lithiation/delithiation,and the doped nitrogen improves the electrical conductivity of HPNC and increases the utilization of Se.When applied as a scaffold for Se in a lithium-selenium battery,the Se/HPNC cathode with a large Se content of 67.6 wt% maintains a high discharge capacity of 410 mAh·g^(-1) at the 500 th cycle at1.0 C,and it demonstrates a discharge capacity as high as371 mAh·g^(-1) even at a high current density of 5.0 C.Moreover,when the current density returns to 0.2 C,the discharge capacity recovers to 527 mAh·g^(-1) with a capacity retention rate of 90.5% for the first 0.2 C,indicating the excellent structural stability of HPNC.HPNC has significant potential for application in energy storage systems.展开更多
基金financially supported by the National Natural Science Foundation of China (Nos.21975110 and 21972058)Taishan Youth Scholar Program of Shandong Province
文摘The reasonable employment of cocatalyst in photocatalysis can effectively promote the photocatalytic H_(2)production activity.In this study,carbon hollow spheres(C),as a good conductive nonmetallic material,have been utilized as a novel cocatalyst and a matrix for loading the Cu-doped-TiO_(2)nanoparticles by a successive hydrother-mal method and metal molten salt method.The Cu-doped-TiO_(2)nanoparticles were tightly anchored on the surface of carbon hollow sphere to form a zero-dimensional/three dimensional(0D/3D)Cu-doped-TiO2/C heterojunction.The optimal Cu-doped-TiO_(2)/C heterojunction demon-strated greatly enhanced photocatalytic H_(2) generation activity(14.4 mmol·g^(-1)·h^(-1))compared with TiO_(2)(0.33 mmol·g^(-1)·h^(-1))and TiO_(2)/C(0.7 mmol·g^(-1)·h^(-1)).The performance improvement was mainly due to the syner-gistic effect of carbon hollow sphere cocatalyst and Cu-doping,the Cu-doping in TiO_(2)nanoparticles can minimize charge recombination and enhance the available photoex-cited electrons,while the 3D carbon hollow spheres can act as electron traps to accelerate the charge separation and offer abundant active sites for solar water splitting reaction.
基金financially supported by the National Natural Science Foundation of China (Nos.52002037 and 51772090)the Scientific Research Fund of Hunan ProvincialEducation Department (No.21B0758)+1 种基金the Natural Science Foundation of Hunan Province (No.2020JJ4272)the Education Department of Hunan Province (No.19C0576)。
文摘Hierarchically porous nitrogen-doped carbon(HPNC) with interconnected micro-,meso-,and macropores was generated from KOH and urea etching as a carbon scaffold to infuse Se.In this structure,micropores confine Se as single-chain molecules,preventing the generation of higher-order polyselenides,the mesopores provide effective pathways for electrolyte diffusion and ion transport and offer sufficient void space to accommodate the volume change of Se upon lithiation/delithiation,and the doped nitrogen improves the electrical conductivity of HPNC and increases the utilization of Se.When applied as a scaffold for Se in a lithium-selenium battery,the Se/HPNC cathode with a large Se content of 67.6 wt% maintains a high discharge capacity of 410 mAh·g^(-1) at the 500 th cycle at1.0 C,and it demonstrates a discharge capacity as high as371 mAh·g^(-1) even at a high current density of 5.0 C.Moreover,when the current density returns to 0.2 C,the discharge capacity recovers to 527 mAh·g^(-1) with a capacity retention rate of 90.5% for the first 0.2 C,indicating the excellent structural stability of HPNC.HPNC has significant potential for application in energy storage systems.