The aerobic,selective oxidation of hydrocarbons via C-H bond activation is still a challenge.This work shows the achievement of the room temperature visible light driven photocatalytic activation of benzylic C-H bonds...The aerobic,selective oxidation of hydrocarbons via C-H bond activation is still a challenge.This work shows the achievement of the room temperature visible light driven photocatalytic activation of benzylic C-H bonds with N-hydroxysuccinimide over BiOBr_(x)I_(1-x)(0≤x≤1)solid solutions,whose valance bands were engineered through varying the ratio of bromide to iodide.The optimal BiOBr0.85I0.15 catalyst exhibited over 98%conversion ratio of ethylbenzene,which was about 3.9 and 8.9 times that of pure BiOBr and BiOI,respectively.The excellent photocatalytic activity of BiOBr0.85I0.15 solid solution can be ascribed to the orbital hybridization of the valence band containing both Br 4p and I 5p orbitals,which could promote photo-induced charge carrier separation and improve the generation of singlet oxygen.This work shed some light on the rational design of photocatalysts for targeted organic transformation.展开更多
Ternary sulfide solid solutions have garnered great attention in photocatalytic water splitting due to their tunable electronic property,low cost,and sufficient light-absorption performance.Herein,a series of Mn_(x)Cd...Ternary sulfide solid solutions have garnered great attention in photocatalytic water splitting due to their tunable electronic property,low cost,and sufficient light-absorption performance.Herein,a series of Mn_(x)Cd_(1-x)S samples with different Mn/Cd molar ratios were synthesized by solvothermal method and used for photocatalytic hydrogen production under visible light.The Mn_(0.2)Cd_(0.8)S and Mn_(0.4)Cd_(0.6)S are demonstrated to be the solid so-lutions,while Mn_(0.6)Cd_(0.4)S and Mn_(0.8)Cd_(0.2)S consist of Mn_(x)Cd_(1-x)S solid solution and MnS.In addition,the Mn_(0.4)Cd_(0.6)S exhibits the highest photocatalytic performance with the H_(2) production rate of 185.95μmol·h^(-1),which is 4.7 times higher than that of CdS.Without cocatalyst,the quantum efficiency of Mn_(0.4)Cd_(0.6)S reaches 2.04%at 400 nm.In addition,the Mn_(0.4)Cd_(0.6)S solid solution also shows high stability during the photocatalytic H_(2) production reaction.The effect of Mn/Cd molar ratio on the microstructure,band gap structure,and photo-catalytic hydrogen production performance of Mn_(x)Cd_(1-x)S was revealed systematically.The excellent photo-catalytic H_(2) production performance of Mn_(0.4)Cd_(0.6)S solid solution is mainly due to its enhanced reducing potential and high charge separation efficiency.展开更多
The 93 W and Mo1 refractory metals were bonded with different Cu_(1-x)Ni_(x) coating interlayers of various Ni content using plasma-activated sintering at 700℃.The effects of the Ni content in the Cu_(1-x)Ni_(x) coat...The 93 W and Mo1 refractory metals were bonded with different Cu_(1-x)Ni_(x) coating interlayers of various Ni content using plasma-activated sintering at 700℃.The effects of the Ni content in the Cu_(1-x)Ni_(x) coating interlayer on the interfacial microstructure evolution and mechanical properties of the W/Mo joints were studied.The maximum average shear strength of the W/Mo joint was 316.5 MPa when the Ni content of the Cu_(1-x)Ni_(x) coating interlayer was 25%.When the Ni content of the Cu_(1-x)Ni_(x) coating interlayer was below 50%,the atomic diffusion at the W/Mo joint interface was adequate without the formation of intermetallic compounds,as demonstrated by the High Resolution Transmission Electron Microscope analyses of the joints.The presence of Ni in Cu_(1-x)Ni_(x) promoted diffusion bonding at the interface,which contributed to the high mechanical properties of the W/Mo joint.With an increase in the Ni content of the Cu_(1-x)Ni_(x) coating interlayer,the Mo Ni intermetallic compound(IMC)nucleated and grew at the Cu1-xNix coating/Mo1 interface.When the Ni content of the Cu_(1-x)Ni_(x) coating interlayer was above 50%,the generation of a brittle Mo Ni IMC weakened the shear strength of the W/Mo joint dramatically.展开更多
Hetero-element doped lithium orthosilicates have been considered as advanced tritium breeders due to the superior performances.In this work,Li_(4)Si_(1-x)Ti_(x)O_(4) ceramics were prepared by proprietary hydrothermal ...Hetero-element doped lithium orthosilicates have been considered as advanced tritium breeders due to the superior performances.In this work,Li_(4)Si_(1-x)Ti_(x)O_(4) ceramics were prepared by proprietary hydrothermal process and multistage reactive sintering.The reaction mechanism of Li_(4)Si_(1-x)Ti_(x)O_(4) was put forward.XRD and SEM analyses indicate that insertion of Ti leads to lattice expansion,which promotes the grain growth and changes the fracture mode.The compressive tests show that the crush load increases almost four times by increasing x from 0 to 0.2.However,the thermal conductivity and ionic conductivity are the best when x=0.05 and x=0.1,respectively.Thermal cycling stability of Li_(4)Si_(1-x)Ti_(x)O_(4) pebbles was further appraised through investigating the changes of microstructure and crush load.After undergoing thermal cycling,the Li_(4)Si_(1-x)Ti_(x)O_(4) still show higher crush load compared with Li_(4)SiO_(4),despite Ti segregation in some samples.The x=0.05 sample exhibits excellent thermal cycling stability.In summary,proper amount of Ti doping can improve the crush load,thermal and ionic conductivity,and thermal cycling stability of Li_(4)SiO_(4).展开更多
基金supported by the National Natural Science Foundation of China(No.21671176)Post-doctoral Foundation of Henan。
文摘The aerobic,selective oxidation of hydrocarbons via C-H bond activation is still a challenge.This work shows the achievement of the room temperature visible light driven photocatalytic activation of benzylic C-H bonds with N-hydroxysuccinimide over BiOBr_(x)I_(1-x)(0≤x≤1)solid solutions,whose valance bands were engineered through varying the ratio of bromide to iodide.The optimal BiOBr0.85I0.15 catalyst exhibited over 98%conversion ratio of ethylbenzene,which was about 3.9 and 8.9 times that of pure BiOBr and BiOI,respectively.The excellent photocatalytic activity of BiOBr0.85I0.15 solid solution can be ascribed to the orbital hybridization of the valence band containing both Br 4p and I 5p orbitals,which could promote photo-induced charge carrier separation and improve the generation of singlet oxygen.This work shed some light on the rational design of photocatalysts for targeted organic transformation.
基金supported by the National Natural Science Foundation of China(22208065,22078074)Natural Science Foundation of Guangxi Province(2022GXNSFBA035483,2020GXNSFDA297007)+2 种基金Opening Project of Guangxi Key Laboratory of Petrochemical Resource Processing and Process Intensification Technology(2021K009)Special Funding for‘Guangxi Bagui Scholars’National College Students'Innovation and Entrepreneurship Training Programs(202210593011).
文摘Ternary sulfide solid solutions have garnered great attention in photocatalytic water splitting due to their tunable electronic property,low cost,and sufficient light-absorption performance.Herein,a series of Mn_(x)Cd_(1-x)S samples with different Mn/Cd molar ratios were synthesized by solvothermal method and used for photocatalytic hydrogen production under visible light.The Mn_(0.2)Cd_(0.8)S and Mn_(0.4)Cd_(0.6)S are demonstrated to be the solid so-lutions,while Mn_(0.6)Cd_(0.4)S and Mn_(0.8)Cd_(0.2)S consist of Mn_(x)Cd_(1-x)S solid solution and MnS.In addition,the Mn_(0.4)Cd_(0.6)S exhibits the highest photocatalytic performance with the H_(2) production rate of 185.95μmol·h^(-1),which is 4.7 times higher than that of CdS.Without cocatalyst,the quantum efficiency of Mn_(0.4)Cd_(0.6)S reaches 2.04%at 400 nm.In addition,the Mn_(0.4)Cd_(0.6)S solid solution also shows high stability during the photocatalytic H_(2) production reaction.The effect of Mn/Cd molar ratio on the microstructure,band gap structure,and photo-catalytic hydrogen production performance of Mn_(x)Cd_(1-x)S was revealed systematically.The excellent photo-catalytic H_(2) production performance of Mn_(0.4)Cd_(0.6)S solid solution is mainly due to its enhanced reducing potential and high charge separation efficiency.
基金the National Natural Science Foundation of China(Nos.51572208 and 51521001)the 111 Project(No.B13035)the Joint Fund(No.6141A02022255)。
文摘The 93 W and Mo1 refractory metals were bonded with different Cu_(1-x)Ni_(x) coating interlayers of various Ni content using plasma-activated sintering at 700℃.The effects of the Ni content in the Cu_(1-x)Ni_(x) coating interlayer on the interfacial microstructure evolution and mechanical properties of the W/Mo joints were studied.The maximum average shear strength of the W/Mo joint was 316.5 MPa when the Ni content of the Cu_(1-x)Ni_(x) coating interlayer was 25%.When the Ni content of the Cu_(1-x)Ni_(x) coating interlayer was below 50%,the atomic diffusion at the W/Mo joint interface was adequate without the formation of intermetallic compounds,as demonstrated by the High Resolution Transmission Electron Microscope analyses of the joints.The presence of Ni in Cu_(1-x)Ni_(x) promoted diffusion bonding at the interface,which contributed to the high mechanical properties of the W/Mo joint.With an increase in the Ni content of the Cu_(1-x)Ni_(x) coating interlayer,the Mo Ni intermetallic compound(IMC)nucleated and grew at the Cu1-xNix coating/Mo1 interface.When the Ni content of the Cu_(1-x)Ni_(x) coating interlayer was above 50%,the generation of a brittle Mo Ni IMC weakened the shear strength of the W/Mo joint dramatically.
基金supported by National Natural Science Foundation of China(No.51802257)Natural Science Foundation of Shaanxi Provincial Department of Education(18JK0570)China Postdoctoral Science Foundation(2019M663788).
文摘Hetero-element doped lithium orthosilicates have been considered as advanced tritium breeders due to the superior performances.In this work,Li_(4)Si_(1-x)Ti_(x)O_(4) ceramics were prepared by proprietary hydrothermal process and multistage reactive sintering.The reaction mechanism of Li_(4)Si_(1-x)Ti_(x)O_(4) was put forward.XRD and SEM analyses indicate that insertion of Ti leads to lattice expansion,which promotes the grain growth and changes the fracture mode.The compressive tests show that the crush load increases almost four times by increasing x from 0 to 0.2.However,the thermal conductivity and ionic conductivity are the best when x=0.05 and x=0.1,respectively.Thermal cycling stability of Li_(4)Si_(1-x)Ti_(x)O_(4) pebbles was further appraised through investigating the changes of microstructure and crush load.After undergoing thermal cycling,the Li_(4)Si_(1-x)Ti_(x)O_(4) still show higher crush load compared with Li_(4)SiO_(4),despite Ti segregation in some samples.The x=0.05 sample exhibits excellent thermal cycling stability.In summary,proper amount of Ti doping can improve the crush load,thermal and ionic conductivity,and thermal cycling stability of Li_(4)SiO_(4).
