The introduction of small size non-metal elements(e.g.,oxygen)into solid solution alloys may be a promising strategy for fabricating efficient Pt-based catalysts with high activity and stability toward oxygen reductio...The introduction of small size non-metal elements(e.g.,oxygen)into solid solution alloys may be a promising strategy for fabricating efficient Pt-based catalysts with high activity and stability toward oxygen reduction reaction(ORR).Herein,oxygen interstitially inserted PtCu(O-PtCu)alloys are firstly designed by an oxygen-microalloying strategy,through ultraviolet(UV)irradiation-assisted galvanic replacement in an aqueous solution containing H_(2)PtCl_(6) and Cu_(2)O nanowires as sacrificial templates.The obtained O-PtCu alloys feature a typical face-centered cubic(FCC)structure with majority Pt,Cu atoms as building bricks and trace interstitial oxygen(1.65 wt.%)existed in the octahedral sites surrounding Cu atoms,leading to a short-range disordered structure.The alloy reaches a recorded half-wave potential of 0.96 V(vs.reversible hydrogen electrode(RHE))and mass activity of 0.48 A·mgPt^(−1),much higher than those of commercial Pt/C.During the accelerated degradation test(ADT),the mass activity lost only 4.2%after 10k cycles,while the commercial Pt/C lost 66.7%under the same conditions.Compared with pure Pt and undoped PtCu alloy,the remarkably improved performance can be attributed to the lattice distortion and energy band reconstruction caused by the interstitial oxygen atoms in form of Cu–O bonds.Moreover,the stable Cu–O bonds delay the possible place exchange between surface Pt atoms and surface-adsorbed oxygen species,thereby hindering Pt dissolution,providing a new paradigm to address Pt degradation issue.Therefore,the introduction of interstitial oxygen into Pt-based alloys may be a facile and smart strategy for the development of advanced Pt-based alloys electrocatalysts.展开更多
Severe mechanical fractu re and unstable interphase,associated with the large volumetric expansion/contraction,significantly hinder the application of high-capacity SiO_(x)materials in lithium-ion batteries.Herein,we ...Severe mechanical fractu re and unstable interphase,associated with the large volumetric expansion/contraction,significantly hinder the application of high-capacity SiO_(x)materials in lithium-ion batteries.Herein,we report the design and facile synthesis of a layer stacked SiO_(x)microparticle(LS-SiO_(x))material,which presents a stacking structure of SiO_(x)layers with abundant disconnected interstices.This LS-SiO_(x)microparticle can effectively accommodate the volume expansion,while ensuring negligible particle expansion.More importantly,the interstices within SiO_(x)microparticle are disconnected from each other,which efficiently prevent the electrolyte from infiltration into the interior,achieving stable electrode/-electrolyte interface.Accordingly,the LS-SiO_(x)material without any coating delivers ultrahigh average Coulombic efficiency,outstanding cycling stability,and full-cell applicability.Only 6 cycles can attain>99.92%Coulombic efficiency and the capacity retention at 0.05 A g^(-1)for 100 cycles exceeds99%.After 800 cycles at 1 A g^(-1),the thickness swelling of LS-SiO_(x)electrode is as low as 0.87%.Moreover,the full cell with pure LS-SiO_(x)anode exhibits capacity retention of 91.2%after 300 cycles at 0.2 C.This work provides a novel concept and effective approach to rationally design silicon-based and other electrode materials with huge volume variation for electrochemical energy storage applications.展开更多
为探究不同土壤水吸力对控释尿素养分释放的影响,根据供试壤质砂土的水分特征曲线设置了6种不同土壤水吸力的处理,采用25℃恒温土壤模拟实验,测定土壤中控释尿素的养分释放特征。结果表明,土壤水吸力为0 k Pa时恒温土壤培养法与静水浸...为探究不同土壤水吸力对控释尿素养分释放的影响,根据供试壤质砂土的水分特征曲线设置了6种不同土壤水吸力的处理,采用25℃恒温土壤模拟实验,测定土壤中控释尿素的养分释放特征。结果表明,土壤水吸力为0 k Pa时恒温土壤培养法与静水浸提法测得的控释尿素养分释放特征无显著差异。土壤水吸力为75 k Pa、30 k Pa和0 k Pa的3个处理,测定的土壤孔隙中空气相对湿度均为95%以上,土壤水汽饱和,释放期基本相同,表明在不考虑水分流动及养分扩散状况影响时,土壤水分条件已不再是影响控释尿素养分释放的主要因素。土壤水吸力525 k Pa和260 k Pa(土壤孔隙中空气相对湿度分别为84%和91%)时释放期分别为416.4 d和120.0 d,相对于土壤水饱和时释放期(63.6 d)的相对相差分别为146.8%和59.1%,远超过《控释肥料》行业标准规定的允许差(20%),表明控释尿素的释放率和释放期受到土壤水吸力过高的抑制。土壤水吸力大小直接影响土壤孔隙空气湿度的饱和与否,土壤水吸力对控释尿素养分释放的影响通过土壤水汽作用于肥料颗粒实现。展开更多
基金supported by the National Natural Science Foundation of China(No.22278016).
文摘The introduction of small size non-metal elements(e.g.,oxygen)into solid solution alloys may be a promising strategy for fabricating efficient Pt-based catalysts with high activity and stability toward oxygen reduction reaction(ORR).Herein,oxygen interstitially inserted PtCu(O-PtCu)alloys are firstly designed by an oxygen-microalloying strategy,through ultraviolet(UV)irradiation-assisted galvanic replacement in an aqueous solution containing H_(2)PtCl_(6) and Cu_(2)O nanowires as sacrificial templates.The obtained O-PtCu alloys feature a typical face-centered cubic(FCC)structure with majority Pt,Cu atoms as building bricks and trace interstitial oxygen(1.65 wt.%)existed in the octahedral sites surrounding Cu atoms,leading to a short-range disordered structure.The alloy reaches a recorded half-wave potential of 0.96 V(vs.reversible hydrogen electrode(RHE))and mass activity of 0.48 A·mgPt^(−1),much higher than those of commercial Pt/C.During the accelerated degradation test(ADT),the mass activity lost only 4.2%after 10k cycles,while the commercial Pt/C lost 66.7%under the same conditions.Compared with pure Pt and undoped PtCu alloy,the remarkably improved performance can be attributed to the lattice distortion and energy band reconstruction caused by the interstitial oxygen atoms in form of Cu–O bonds.Moreover,the stable Cu–O bonds delay the possible place exchange between surface Pt atoms and surface-adsorbed oxygen species,thereby hindering Pt dissolution,providing a new paradigm to address Pt degradation issue.Therefore,the introduction of interstitial oxygen into Pt-based alloys may be a facile and smart strategy for the development of advanced Pt-based alloys electrocatalysts.
基金the support of the National Natural Science Foundation of China(51634003)。
文摘Severe mechanical fractu re and unstable interphase,associated with the large volumetric expansion/contraction,significantly hinder the application of high-capacity SiO_(x)materials in lithium-ion batteries.Herein,we report the design and facile synthesis of a layer stacked SiO_(x)microparticle(LS-SiO_(x))material,which presents a stacking structure of SiO_(x)layers with abundant disconnected interstices.This LS-SiO_(x)microparticle can effectively accommodate the volume expansion,while ensuring negligible particle expansion.More importantly,the interstices within SiO_(x)microparticle are disconnected from each other,which efficiently prevent the electrolyte from infiltration into the interior,achieving stable electrode/-electrolyte interface.Accordingly,the LS-SiO_(x)material without any coating delivers ultrahigh average Coulombic efficiency,outstanding cycling stability,and full-cell applicability.Only 6 cycles can attain>99.92%Coulombic efficiency and the capacity retention at 0.05 A g^(-1)for 100 cycles exceeds99%.After 800 cycles at 1 A g^(-1),the thickness swelling of LS-SiO_(x)electrode is as low as 0.87%.Moreover,the full cell with pure LS-SiO_(x)anode exhibits capacity retention of 91.2%after 300 cycles at 0.2 C.This work provides a novel concept and effective approach to rationally design silicon-based and other electrode materials with huge volume variation for electrochemical energy storage applications.
文摘为探究不同土壤水吸力对控释尿素养分释放的影响,根据供试壤质砂土的水分特征曲线设置了6种不同土壤水吸力的处理,采用25℃恒温土壤模拟实验,测定土壤中控释尿素的养分释放特征。结果表明,土壤水吸力为0 k Pa时恒温土壤培养法与静水浸提法测得的控释尿素养分释放特征无显著差异。土壤水吸力为75 k Pa、30 k Pa和0 k Pa的3个处理,测定的土壤孔隙中空气相对湿度均为95%以上,土壤水汽饱和,释放期基本相同,表明在不考虑水分流动及养分扩散状况影响时,土壤水分条件已不再是影响控释尿素养分释放的主要因素。土壤水吸力525 k Pa和260 k Pa(土壤孔隙中空气相对湿度分别为84%和91%)时释放期分别为416.4 d和120.0 d,相对于土壤水饱和时释放期(63.6 d)的相对相差分别为146.8%和59.1%,远超过《控释肥料》行业标准规定的允许差(20%),表明控释尿素的释放率和释放期受到土壤水吸力过高的抑制。土壤水吸力大小直接影响土壤孔隙空气湿度的饱和与否,土壤水吸力对控释尿素养分释放的影响通过土壤水汽作用于肥料颗粒实现。
