The substitution of TiO_(2)for SiO_(2)in Y_(2)O_(3)-Li_(2)O-Al_(2)O_(3)-SiO_(2)(YLAS)glass-ceramics significantly altered their crystallization behavior and properties.Introducing TiO_(2)reduced the glass transition t...The substitution of TiO_(2)for SiO_(2)in Y_(2)O_(3)-Li_(2)O-Al_(2)O_(3)-SiO_(2)(YLAS)glass-ceramics significantly altered their crystallization behavior and properties.Introducing TiO_(2)reduced the glass transition temperature while increasing the crystallization peak temperature and lowering activation energy,which facilitated crystallization.The crystal growth shifted from three-dimensional to two-dimensional,and the primary phases transitioned from Al_(9.83)Zr_(0.17)and Y_(2)Si_(2)O_(7)to Y_(4.67)(SiO_(4))_(3)O,though crystal morphology remained unchanged.Grain size increased with higher crystallization temperatures.Mechanically,Vickers hardness slightly decreased(from 796 to 784 Hv),while bending strength improved(from 141 to 146 MPa),suggesting that TiO_(2)enhanced toughness without compromising structural integrity.The strength of the glass can be further improved through two-step ion exchange,but excessive crystallization can lead to cracks on the glass surface due to excessive surface compressive stress,resulting in a decrease in bending strength.These findings provide critical insights for optimizing YLAS glass-ceramics for advanced applications.展开更多
The scaling-up of electrochemical CO_(2)reduction requires circumventing the CO_(2)loss as carbonates under alkaline conditions.Zero-gap MEA cell configurations with a proton exchange membrane represent an alternative...The scaling-up of electrochemical CO_(2)reduction requires circumventing the CO_(2)loss as carbonates under alkaline conditions.Zero-gap MEA cell configurations with a proton exchange membrane represent an alternative solution in a pure acidic system,but the catalyst layer in direct contact with the hydrated proton environment usually leads to H_(2)evolution dominating.Herein,we show that polydimethyldiallyl-ammonium-chloride-coated Ag(Ag@PDDA)electrode exhibits outstanding performance with a FE of 86%,a single-pass conversion of 72%,and a stability of 28 h for CO production in pure-acid MEA compared with ammonium poly(N-methyl-piperidine-co-pterphenyl)decorated Ag(Ag/QAPPT)and cetyltrimethylammonium bromide decorated Ag(Ag/CTAB).The in situ ATR-SEIRAS reveal that PDDA creates a positive charge-rich protective outer layer and an N-rich hybrid inner layer,which not only suppresses the migration of H+during the electrolysis process and blocks the direct contact between H2O and Ag catalyst,but also promotes the generation from CO_(2)to*COOH in a pure-acid system.This work highlights the importance of polyelectrolyte engineering in regulating the electrocatalytic interface and accelerates the development of proton exchange membrane CO_(2)electrolysis.展开更多
Efficient alkaline hydrogen evolution reaction(HER)catalysts are critical for anion exchange membrane water electrolysis(AEMWE).However,the intrinsic scaling relationship between water dissociation and OH desorption f...Efficient alkaline hydrogen evolution reaction(HER)catalysts are critical for anion exchange membrane water electrolysis(AEMWE).However,the intrinsic scaling relationship between water dissociation and OH desorption fundamentally impedes designing catalysts requiring concurrent superior water dissociation and facile OH desorption.Here,we engineer a superhydrophilic Ru/Cr_(2)O_(3) heterostructured electrocatalyst through in situ confinement of Ru nanoparticles(5-10 nm)within a Cr_(2)O_(3) matrix.Acting as a Lewis acid,the Cr_(2)O_(3) component provides alternative sites for water dissociation,accelerating the Volmer step kinetics and downshifting the Ru d-band center via interfacial charge transfer,while simultaneously adsorbing OH-to form a surface-bound Lewis base that repels excess OH-from Ru sites,thereby suppressing hydroxyl over-adsorption.Concurrently,the superhydrophilic surface architecture promotes efficient hydrogen bubble release,thereby reducing mass transport resistance.As a result,the Ru/Cr_(2)O_(3) heterostructured electrocatalyst exhibits an ultralow overpotential of 36.7 mV at 10 mA cm^(-2) and a Tafel slope of 33.2 mV dec^(-1).Integrated into an AEMWE device,the electrode delivers500 mA cm^(-2) for 2000 h in 1.0 M KOH,underscoring its industrial viability(hydrogen production energy consumption per cubic meter(EW):3.94 kW h m^(-3);electricity-to-hydrogen energy conversion efficiency(η_(ETH)):89%@80℃).展开更多
基金Funded by the China Building Material Federation Projects(Nos.20221JBGS06-19 and 2023JBGS02-01)。
文摘The substitution of TiO_(2)for SiO_(2)in Y_(2)O_(3)-Li_(2)O-Al_(2)O_(3)-SiO_(2)(YLAS)glass-ceramics significantly altered their crystallization behavior and properties.Introducing TiO_(2)reduced the glass transition temperature while increasing the crystallization peak temperature and lowering activation energy,which facilitated crystallization.The crystal growth shifted from three-dimensional to two-dimensional,and the primary phases transitioned from Al_(9.83)Zr_(0.17)and Y_(2)Si_(2)O_(7)to Y_(4.67)(SiO_(4))_(3)O,though crystal morphology remained unchanged.Grain size increased with higher crystallization temperatures.Mechanically,Vickers hardness slightly decreased(from 796 to 784 Hv),while bending strength improved(from 141 to 146 MPa),suggesting that TiO_(2)enhanced toughness without compromising structural integrity.The strength of the glass can be further improved through two-step ion exchange,but excessive crystallization can lead to cracks on the glass surface due to excessive surface compressive stress,resulting in a decrease in bending strength.These findings provide critical insights for optimizing YLAS glass-ceramics for advanced applications.
基金financial support of the National Natural Science Foundation of China(NSFC)(52394202,52021004,52301232,and 52476056)the Natural Science Foundation of Chongqing Province(2024NSCQ-MSX1109).
文摘The scaling-up of electrochemical CO_(2)reduction requires circumventing the CO_(2)loss as carbonates under alkaline conditions.Zero-gap MEA cell configurations with a proton exchange membrane represent an alternative solution in a pure acidic system,but the catalyst layer in direct contact with the hydrated proton environment usually leads to H_(2)evolution dominating.Herein,we show that polydimethyldiallyl-ammonium-chloride-coated Ag(Ag@PDDA)electrode exhibits outstanding performance with a FE of 86%,a single-pass conversion of 72%,and a stability of 28 h for CO production in pure-acid MEA compared with ammonium poly(N-methyl-piperidine-co-pterphenyl)decorated Ag(Ag/QAPPT)and cetyltrimethylammonium bromide decorated Ag(Ag/CTAB).The in situ ATR-SEIRAS reveal that PDDA creates a positive charge-rich protective outer layer and an N-rich hybrid inner layer,which not only suppresses the migration of H+during the electrolysis process and blocks the direct contact between H2O and Ag catalyst,but also promotes the generation from CO_(2)to*COOH in a pure-acid system.This work highlights the importance of polyelectrolyte engineering in regulating the electrocatalytic interface and accelerates the development of proton exchange membrane CO_(2)electrolysis.
基金supported by the National Natural Science Foundation of China(22479113,52101268)the Fundamental Research Funds for the Central Universities(buctrc202323)。
文摘Efficient alkaline hydrogen evolution reaction(HER)catalysts are critical for anion exchange membrane water electrolysis(AEMWE).However,the intrinsic scaling relationship between water dissociation and OH desorption fundamentally impedes designing catalysts requiring concurrent superior water dissociation and facile OH desorption.Here,we engineer a superhydrophilic Ru/Cr_(2)O_(3) heterostructured electrocatalyst through in situ confinement of Ru nanoparticles(5-10 nm)within a Cr_(2)O_(3) matrix.Acting as a Lewis acid,the Cr_(2)O_(3) component provides alternative sites for water dissociation,accelerating the Volmer step kinetics and downshifting the Ru d-band center via interfacial charge transfer,while simultaneously adsorbing OH-to form a surface-bound Lewis base that repels excess OH-from Ru sites,thereby suppressing hydroxyl over-adsorption.Concurrently,the superhydrophilic surface architecture promotes efficient hydrogen bubble release,thereby reducing mass transport resistance.As a result,the Ru/Cr_(2)O_(3) heterostructured electrocatalyst exhibits an ultralow overpotential of 36.7 mV at 10 mA cm^(-2) and a Tafel slope of 33.2 mV dec^(-1).Integrated into an AEMWE device,the electrode delivers500 mA cm^(-2) for 2000 h in 1.0 M KOH,underscoring its industrial viability(hydrogen production energy consumption per cubic meter(EW):3.94 kW h m^(-3);electricity-to-hydrogen energy conversion efficiency(η_(ETH)):89%@80℃).
