We address the composition-controlled synthesis of monodispersed AgPd alloy nanoparticles （NPs）, their assembly for the first time on mesoporous graphitic carbon nitride （mpg-C3N4）, and the unprecedented catalysis...We address the composition-controlled synthesis of monodispersed AgPd alloy nanoparticles （NPs）, their assembly for the first time on mesoporous graphitic carbon nitride （mpg-C3N4）, and the unprecedented catalysis of mpg-CgN4@AgPd in the hydrolytic dehydrogenation of ammonia borane （AB） at room temperature. Monodispersed AgPd alloy NPs were synthesized using a high-temperature organic-phase surfactant-assisted protocol comprising the co-reduction of silver（I） acetate and palladium（II） acetylacetonate in the presence of oleylamine, oleic acid, and 1-0ctadecene. This protocol allowed the synthesis of four different compositions of AgPd alloy NPs. The AgPd alloy NPs were then assembled on mpg-C3N4, reduced graphene oxide, and Ketjenblack using a liquid-phase self-assembly method. Among the three supports tested, the mpg-CBN4@AgPd catalysts provided the best activity because of the Mott-Schottky effect, which was driven by the favorable work function difference between mpg-CBN4 and the metal NPs. Moreover, the activity of the mpg-CBN4@AgPd catalyst was further enhanced by an acetic acid treatment （AAt）, and a record initial turnover frequency of 94.1 mOl（hydrogen）＇mOl（catalyst）-l-min-1 was obtained. Furthermore, the mpg-CBN4@Ag42Pdss-AAt catalyst also showed moderate durability for the hydrolysis of AB. This study also includes a wealth of kinetic data for the mpg-CBN4@AgPd-catalyzed hydrolysis of AB.展开更多
Carbon coati ng has bee n a routi ne strategy for improvi ng the performa nee of Si-based anode materials for lithium-ion batteries. The ability to tailor the thick ness, homoge neity and graph itizati on degree of ca...Carbon coati ng has bee n a routi ne strategy for improvi ng the performa nee of Si-based anode materials for lithium-ion batteries. The ability to tailor the thick ness, homoge neity and graph itizati on degree of carb on-coati ng layers is esse ntial for addressi ng issues that hamper the real applicatio ns of Si anodes. Herein, we report the con structio n of two-dime nsional (2D) assemblies of intercon nected Si @ graphitic carb on yolk-shell nano particles (2D-Si@gC) from commercial Si powders by exploiting oleic acid (OA). The OA molecules act as both the surface-coati ng liga nds for facilitating 2D nano particle assembly and the precursor for forming uniform and conformal graphitic shells as thin as 4 nm. The as-prepared 2D-Si@gC with rationally designed void space exhibits excellent rate capability and cycling stability when used as anode materials for lithium-ion batteries, delivering a capacity of 1,150 mAh·g^-1 at an ultrahigh current density of 10 A·g^-1 and maintaining a stabilized capacity of 1,275 mAh·g^-1 after 200 cycles at 4 A·g^-1 The formatio n of yolk-shell nano particles 8nfines the depositi on of solid electrolyte in terphase (SEI) onto the outer carb on shell, while simulta neously providing sufficie nt space for volumetric expa nsion of Si nano particles. These attributes effectively mitigate the thickness variations of the entire electrode during repeated lithiation and delithiation, which combined with the unique 2D architecture and interc onn ected graphitic carbon shells of 2D-Si@gC contributes to its superior rate capability and cycling performa nee.展开更多
A simple and effective photoelectrochemical sensor was fabricated by Cu/graphitic carbon nitride （Cu/g- CN） composites for detecting bisphenol A. The Cu/g-CN composites were obtained via a solvothermal process in th...A simple and effective photoelectrochemical sensor was fabricated by Cu/graphitic carbon nitride （Cu/g- CN） composites for detecting bisphenol A. The Cu/g-CN composites were obtained via a solvothermal process in the presence of the copper-based ionic liquid. In view of localized surface plasmon resonance ofCu nanoparticles, Cu nanoparticles can promote light absorbance and rapid electron transport ofg-CN. As a result, the Cu/g-CN composites obtained greatly enhancement of photocurrent, when compared to the pure g-CN. In addition, the introduction of bisphenol A can hinder electron-hole recombination, resulting in sensitive photoelectrochemical monitoring of bisphenol A. The detection limit of the bisphenol A photoelectrochemical sensor was below 0.012 μmol/L. The bisphenol A photoelectrochemical sensor exhibited an excellent stability and acceptable anti-interference. The photoelectrochemical sensor provided the promising platform to monitor bisphenol A at low concentration in water environment.展开更多
The number of photogenerated carriers involved in the photocatalytic reaction is one of the main factors influencing the photocatalytic activity,and constructing S-scheme heterojunctions can significantly en-hance the...The number of photogenerated carriers involved in the photocatalytic reaction is one of the main factors influencing the photocatalytic activity,and constructing S-scheme heterojunctions can significantly en-hance the migration of photogenerated carriers,which is regarded as an effective method.In this study,Au nanoparticles(NPs)-supported crystallized heptazine/triazine-based carbon nitride(AHTCN)S-scheme heterojunction photocatalysts are successfully prepared by photoreduction methods.Except for the Au NPs function as an electron mediator,the experiment results and DFT calculations demonstrate that the Fermi energy level of crystallized heptazine/triazine-based heterojunction(HTCN)is pulled down after anchoring Au NPs,and thus the electron transfer path of HTCN changed from Type II-scheme to S-scheme.Owing to S-scheme heterojunction,the optimal AHTCN-2(2 wt.%Au loaded)exhibits the best photocat-alytic hydrogen evolution with a production rate of 715.2μmol h^(−1)g^(−1),which significantly outperforms that of the HTCN.This work delivers a new strategy for the construction of S-scheme heterojunctions.展开更多
文摘We address the composition-controlled synthesis of monodispersed AgPd alloy nanoparticles （NPs）, their assembly for the first time on mesoporous graphitic carbon nitride （mpg-C3N4）, and the unprecedented catalysis of mpg-CgN4@AgPd in the hydrolytic dehydrogenation of ammonia borane （AB） at room temperature. Monodispersed AgPd alloy NPs were synthesized using a high-temperature organic-phase surfactant-assisted protocol comprising the co-reduction of silver（I） acetate and palladium（II） acetylacetonate in the presence of oleylamine, oleic acid, and 1-0ctadecene. This protocol allowed the synthesis of four different compositions of AgPd alloy NPs. The AgPd alloy NPs were then assembled on mpg-C3N4, reduced graphene oxide, and Ketjenblack using a liquid-phase self-assembly method. Among the three supports tested, the mpg-CBN4@AgPd catalysts provided the best activity because of the Mott-Schottky effect, which was driven by the favorable work function difference between mpg-CBN4 and the metal NPs. Moreover, the activity of the mpg-CBN4@AgPd catalyst was further enhanced by an acetic acid treatment （AAt）, and a record initial turnover frequency of 94.1 mOl（hydrogen）＇mOl（catalyst）-l-min-1 was obtained. Furthermore, the mpg-CBN4@Ag42Pdss-AAt catalyst also showed moderate durability for the hydrolysis of AB. This study also includes a wealth of kinetic data for the mpg-CBN4@AgPd-catalyzed hydrolysis of AB.
基金A. D. acknowledges the financial support from the National Natural Science Foundation of China (Nos. 21872038 and 21373052)MOST (No. 2017YFA0207303)+1 种基金Key Basic Research Program of Science and Technology Commission of Shanghai Municipality (No. 17JC1400100)D. Y. thanks to the National Natural Science Foundation of China (Nos. 51573030, 51573028 and 51773042).
文摘Carbon coati ng has bee n a routi ne strategy for improvi ng the performa nee of Si-based anode materials for lithium-ion batteries. The ability to tailor the thick ness, homoge neity and graph itizati on degree of carb on-coati ng layers is esse ntial for addressi ng issues that hamper the real applicatio ns of Si anodes. Herein, we report the con structio n of two-dime nsional (2D) assemblies of intercon nected Si @ graphitic carb on yolk-shell nano particles (2D-Si@gC) from commercial Si powders by exploiting oleic acid (OA). The OA molecules act as both the surface-coati ng liga nds for facilitating 2D nano particle assembly and the precursor for forming uniform and conformal graphitic shells as thin as 4 nm. The as-prepared 2D-Si@gC with rationally designed void space exhibits excellent rate capability and cycling stability when used as anode materials for lithium-ion batteries, delivering a capacity of 1,150 mAh·g^-1 at an ultrahigh current density of 10 A·g^-1 and maintaining a stabilized capacity of 1,275 mAh·g^-1 after 200 cycles at 4 A·g^-1 The formatio n of yolk-shell nano particles 8nfines the depositi on of solid electrolyte in terphase (SEI) onto the outer carb on shell, while simulta neously providing sufficie nt space for volumetric expa nsion of Si nano particles. These attributes effectively mitigate the thickness variations of the entire electrode during repeated lithiation and delithiation, which combined with the unique 2D architecture and interc onn ected graphitic carbon shells of 2D-Si@gC contributes to its superior rate capability and cycling performa nee.
基金financially supported by the National Natural Science Foundation of China(No. 41371446)
文摘A simple and effective photoelectrochemical sensor was fabricated by Cu/graphitic carbon nitride （Cu/g- CN） composites for detecting bisphenol A. The Cu/g-CN composites were obtained via a solvothermal process in the presence of the copper-based ionic liquid. In view of localized surface plasmon resonance ofCu nanoparticles, Cu nanoparticles can promote light absorbance and rapid electron transport ofg-CN. As a result, the Cu/g-CN composites obtained greatly enhancement of photocurrent, when compared to the pure g-CN. In addition, the introduction of bisphenol A can hinder electron-hole recombination, resulting in sensitive photoelectrochemical monitoring of bisphenol A. The detection limit of the bisphenol A photoelectrochemical sensor was below 0.012 μmol/L. The bisphenol A photoelectrochemical sensor exhibited an excellent stability and acceptable anti-interference. The photoelectrochemical sensor provided the promising platform to monitor bisphenol A at low concentration in water environment.
基金This work was partially supported by the Jiangxi Province tech-nology innovation guidance project(grant no.20212BDH81036)Jiangxi Provincial Natural Science Foundation(20224BAB213016)+1 种基金the Science and Technology Project of the Education Department of Jiangxi Province(No.GJJ200457)the Jiangxi Province Grad-uate Student Innovation Special Fund Project(No.YC2022-S389).
文摘The number of photogenerated carriers involved in the photocatalytic reaction is one of the main factors influencing the photocatalytic activity,and constructing S-scheme heterojunctions can significantly en-hance the migration of photogenerated carriers,which is regarded as an effective method.In this study,Au nanoparticles(NPs)-supported crystallized heptazine/triazine-based carbon nitride(AHTCN)S-scheme heterojunction photocatalysts are successfully prepared by photoreduction methods.Except for the Au NPs function as an electron mediator,the experiment results and DFT calculations demonstrate that the Fermi energy level of crystallized heptazine/triazine-based heterojunction(HTCN)is pulled down after anchoring Au NPs,and thus the electron transfer path of HTCN changed from Type II-scheme to S-scheme.Owing to S-scheme heterojunction,the optimal AHTCN-2(2 wt.%Au loaded)exhibits the best photocat-alytic hydrogen evolution with a production rate of 715.2μmol h^(−1)g^(−1),which significantly outperforms that of the HTCN.This work delivers a new strategy for the construction of S-scheme heterojunctions.
