The catalytic performance of Pt-based catalysts depends sensitively on their d-band centers.Nevertheless,there are still huge challenges to evaluate their d-band centers from experimental technologies,and modulate the...The catalytic performance of Pt-based catalysts depends sensitively on their d-band centers.Nevertheless,there are still huge challenges to evaluate their d-band centers from experimental technologies,and modulate them to analyze their selectivity in ethanol oxidation reaction(EOR).Here,Pt1Au1alloy supported on the commercial carbon material(Pt_(1)Au_(1)/C)is employed as a typical example to investigate its d-band center shift of surface Pt,and as electrocatalysts to study its selectivity towards EOR.Significantly,a highly reliable in situ Fourier-transform infrared spectroscopy CO-probe strategy is developed to characterize the d-band center shift of surface Pt.The modified electronic effect and site effect of Pt_(1)Au_(1)/C dictated the adsorption configuration of intermediate species and the OH species coverage,thereby influencing its selectivity.More importantly,we developed a universal cyclic voltammetry peak differentiation fitting method as an electrochemical analysis technique to investigate CO_(2)selectivity,which is potentially extendable to other Pt-based electrocatalysts.展开更多
The electrochemical oxidation of formic acid has been attracting significant attention in the past few years due to the great potential prospect of direct formic acid fuel cell (DFAFC) in applications, including high ...The electrochemical oxidation of formic acid has been attracting significant attention in the past few years due to the great potential prospect of direct formic acid fuel cell (DFAFC) in applications, including high theoretical open circuit potential (1.48 V), low fuel crossover, high practical power densities at low temperature, facilitating of proton transport in catalyst layers and low toxicity [1-5].展开更多
The recent development of Aurum(Au)introduced Platinum(Pt)based nanomaterials is of great significance to direct methanol fuel cell as electrocatalysts for anode reactions,due to its stability and anti-poisoning featu...The recent development of Aurum(Au)introduced Platinum(Pt)based nanomaterials is of great significance to direct methanol fuel cell as electrocatalysts for anode reactions,due to its stability and anti-poisoning features.Therefore,the performance of PtAu based catalysts with different elements,atomic ratio,and morphology was studied in methanol solution to further improve its electrocatalytic activity.Furthermore,the effects of Au have aroused the researchers'attention in Pt-based nanocatalysts.In this review,we summarize the controllable synthesis,mechanism,and catalytic performance of Au introduced Pt-based electrocatalysts such as PtAu core-shell nanostructures,PtAu dendrite,PtAu nanowires,self-supporting Au@Pt NPs,and Au@Pt star-like nanocrystals for the methanol oxidation reaction.Finally,the challenges and research directions for the future development of PtAu based catalysts are provided.展开更多
Background:Alterations in the expression of human kallikrein-related peptidases(KLKs)have been described in patients with Alzheimer’s disease(AD).We elucidated the suitability of KLK6,KLK8 and KLK10 to distinguish AD...Background:Alterations in the expression of human kallikrein-related peptidases(KLKs)have been described in patients with Alzheimer’s disease(AD).We elucidated the suitability of KLK6,KLK8 and KLK10 to distinguish AD from NC and explored associations with established AD biomarkers.Methods:KLK levels in cerebrospinal fluid(CSF),as determined by ELISA,were compared between 32 AD patients stratified to A/T/(N)system with evidence for amyloid pathology and of 23 normal controls with normal AD biomarkers.Associations between KLK levels and clinical severity,CSF and positron emission tomography(PET)based AD biomarkers were tested for.Results:Levels of KLK6 and KLK10 were significantly increased in AD.KLK6 differed significantly between AD A+/T+/N+and AD A+/T−/N+or NC with an AUC of 0.922.CSF pTau and tTau levels were significantly associated with KLK6 in AD.Conclusions:KLK6 deserves further investigations as a potential biomarker of Tau pathology in AD.展开更多
Herein,we present a new strategy that for the first time achieved chemo- and enantio-selective hydrogenation of alkenes over arylhalides.Key to the success is that instead of using external poisons,we use the composit...Herein,we present a new strategy that for the first time achieved chemo- and enantio-selective hydrogenation of alkenes over arylhalides.Key to the success is that instead of using external poisons,we use the composition of the bimetallic nanocrystal catalysts to control chemoselectivity (hydrogenation of C=C bonds without cleavage of Ar-X bonds).We further show that this system combined with surface modifying chiral ligands can control the enantioselectivity.Thus,after synthesizing and screening a series of easily accessible MxAuy (M = Pd,Pt;x,y= 1,3,5) bimetallic nanocrystals (9-10 nm) supported on activated carbon,we identified that PtiAui/C is a recyclable and generally applicable catalyst for the chemoselective hydrogenation of alkenes without cleaving aryl halogen bonds.Furthermore,cinchonidine modified Pt,Aui/C is shown to be capable of enantioselective hydrogenation,as illustrated by the rapid and enantio-enriched synthesis of RIP1 inhibitor analogue 7-Br-O-Necl.展开更多
Bimetallic nanoparticles(AmBn)usually exhibit rich catalytic chemistry and have drawn tremendous attention in heterogeneous catalysis.However,challenged by the huge configuration space,the understanding toward their c...Bimetallic nanoparticles(AmBn)usually exhibit rich catalytic chemistry and have drawn tremendous attention in heterogeneous catalysis.However,challenged by the huge configuration space,the understanding toward their composition and distribution of A/B element is known little at the atomic level,which hinders the rational synthesis.Herein,we develop an on-the-fly training strategy combing the machine learning model(SchNet)with the genetic algorithm(GA)search technique,which achieve the fast and accurate energy prediction of complex bimetallic clusters at the DFT level.Taking the 38-atom PtmAu38-mnanoparticle as example,the element distribution identification problem and the stability trend as a function of Pt/Au composition is quantitatively re solved.Specifically,results show that on the Pt-rich cluster Au atoms prefer to occupy the low-coordinated surface corner sites and form patch-like surface segregation patte rns,while for the Au-rich ones Pt atoms tend to site in the co re region and form the co re-shell(Pt@Au)configuration.The thermodynamically most stable PtmAu38-mcluster is Pt6 Au32,with all the core-region sites occupied by Pt,rationalized by the stronger Pt-Pt bond in comparison with Pt-Au and Au-Au bonds.This work exemplifies the potent application of rapid global sea rch enabled by machine learning in exploring the high-dimensional configuration space of bimetallic nanocatalysts.展开更多
Inefficient electrocatalysts and high-power consumption are two thorny problems for electrochemical hydrogen(H2)production from acidic water electrolysis.Herein we report the one-pot precise synthesis of ultrafine Au ...Inefficient electrocatalysts and high-power consumption are two thorny problems for electrochemical hydrogen(H2)production from acidic water electrolysis.Herein we report the one-pot precise synthesis of ultrafine Au core-Pt Au alloy shell nanowires(Au@PtxAu UFNWs).Among them,Au@Pt_(0.077) Au UFNWs exhibit the best performance for formic acid oxidation reaction(FAOR)and hydrogen evolution reaction(HER),which only require applied potentials of 0.29 V and-22.6 m V to achieve a current density of 10 m A cm^(-2),respectively.The corresponding formic acid electrolyzer realizes the electrochemical H2 production at a voltage of only 0.51 V with 10 m A cm^(-2) current density.Density functional theory(DFT)calculations reveal that the Au-riched Pt Au alloy structure can facilitates the direct oxidation pathway of FAOR and consequently elevates the FAOR activity of Au@Pt_(0.077) Au UFNWs.This work provides meaningful insights into the electrochemical H_(2) production from both the construction of advanced bifunctional electrocatalysts and the replacement of OER.展开更多
OBJECTIVE Currently, almost all chemical compounds or biological reagents to reverse or slow down the AD process have failed in clinical trials. An integrative and multi-targeted strategy is increasingly appreciated t...OBJECTIVE Currently, almost all chemical compounds or biological reagents to reverse or slow down the AD process have failed in clinical trials. An integrative and multi-targeted strategy is increasingly appreciated to effectively combat this devastating disease. Traditional Chinese medicine(TCM) has been widely used for treatment of dementia, and thus the advantages of the potential therapeutic features of TCM treatment and associated mechanisms should be well taken. The Amnesia Remedy Formula(ARF) was invented by one of the most influential Master of TCM SUN Si-miao, who lived for about 100 year old. The aim of this research is to characterize the time course changes of the cognitive behaviors post a ARF, and the mechanism underlying the effects, focusing on PKA-centered signaling for both enhancement of neural plasticity and clearance of the phosphorylated Tau. RESULTS We tested the efficacy of ARF on two animal models of AD, and examine the central role of PKA signaling in the enhancement of neural plasticity via PKA/CREB/BDNF pathway as well as clearance of toxic p Tau via PKA/GSK3β/p Tau pathway. In the scopolamine model, ARF effectively reversed the memory in Morris water maze(MWM) test, with some features superior to anti-AD drug donepezil. In a battery test of MWM, novel object recognition or T maze in 5-month-old senescenceaccelerated mouse prone 8(SAMP8) strain mice, two weeks of administration of ARF showed overall better improvement in memory loss than donepezil, and the effect lasted for at least 1 week after termination of administration of the formula. ARF increased expression of PKA/CREB/BDNF and synaptic proteins PSD95 expression, as well as enhanced Ser9 phosphorylation of GSK3β, thus reduced p Tau in the hippocampus. Blockade of PKA signaling blunted the anti-AD-like effect of ARF, with reversal of CREB/BDNF signaling. Transcriptomic analysis indicated some changes of novel molecules along this pathway may be part of the pathological and therapeutic mechanism, which warrants further investig展开更多
基金granted by the National Natural Science Foundation of China(22172134,22288102,22279011)Fundamental Research Funds for the Central Universities(2022CDJXY-003)。
文摘The catalytic performance of Pt-based catalysts depends sensitively on their d-band centers.Nevertheless,there are still huge challenges to evaluate their d-band centers from experimental technologies,and modulate them to analyze their selectivity in ethanol oxidation reaction(EOR).Here,Pt1Au1alloy supported on the commercial carbon material(Pt_(1)Au_(1)/C)is employed as a typical example to investigate its d-band center shift of surface Pt,and as electrocatalysts to study its selectivity towards EOR.Significantly,a highly reliable in situ Fourier-transform infrared spectroscopy CO-probe strategy is developed to characterize the d-band center shift of surface Pt.The modified electronic effect and site effect of Pt_(1)Au_(1)/C dictated the adsorption configuration of intermediate species and the OH species coverage,thereby influencing its selectivity.More importantly,we developed a universal cyclic voltammetry peak differentiation fitting method as an electrochemical analysis technique to investigate CO_(2)selectivity,which is potentially extendable to other Pt-based electrocatalysts.
基金supported by the National Natural Science Foundation of China (21433003, 21733004, U1601211, 21811530078)Jilin Province Science and Technology Development Program (20180101030JC, 20160622037JC, 20170203003SF)+1 种基金the Hundred Talents Program of Chinese Academy of Sciences and the Recruitment Program of Foreign Experts (WQ2012220007)RFBR (18-5353025)
文摘The electrochemical oxidation of formic acid has been attracting significant attention in the past few years due to the great potential prospect of direct formic acid fuel cell (DFAFC) in applications, including high theoretical open circuit potential (1.48 V), low fuel crossover, high practical power densities at low temperature, facilitating of proton transport in catalyst layers and low toxicity [1-5].
基金supported by the Guangxi Science and Technology Project(Nos.AA17204083 and AB16380030)the link project of the National Natural Science Foundation of China and Fujian Province(No.U1705252)the Natural Science Foundation of Guangdong Province(No.2015A030312007).
文摘The recent development of Aurum(Au)introduced Platinum(Pt)based nanomaterials is of great significance to direct methanol fuel cell as electrocatalysts for anode reactions,due to its stability and anti-poisoning features.Therefore,the performance of PtAu based catalysts with different elements,atomic ratio,and morphology was studied in methanol solution to further improve its electrocatalytic activity.Furthermore,the effects of Au have aroused the researchers'attention in Pt-based nanocatalysts.In this review,we summarize the controllable synthesis,mechanism,and catalytic performance of Au introduced Pt-based electrocatalysts such as PtAu core-shell nanostructures,PtAu dendrite,PtAu nanowires,self-supporting Au@Pt NPs,and Au@Pt star-like nanocrystals for the methanol oxidation reaction.Finally,the challenges and research directions for the future development of PtAu based catalysts are provided.
基金This work was supported by the German Research Foundation(DFG)and the Technical University of Munich(TUM)in the framework of the Open Access Publishing Program.
文摘Background:Alterations in the expression of human kallikrein-related peptidases(KLKs)have been described in patients with Alzheimer’s disease(AD).We elucidated the suitability of KLK6,KLK8 and KLK10 to distinguish AD from NC and explored associations with established AD biomarkers.Methods:KLK levels in cerebrospinal fluid(CSF),as determined by ELISA,were compared between 32 AD patients stratified to A/T/(N)system with evidence for amyloid pathology and of 23 normal controls with normal AD biomarkers.Associations between KLK levels and clinical severity,CSF and positron emission tomography(PET)based AD biomarkers were tested for.Results:Levels of KLK6 and KLK10 were significantly increased in AD.KLK6 differed significantly between AD A+/T+/N+and AD A+/T−/N+or NC with an AUC of 0.922.CSF pTau and tTau levels were significantly associated with KLK6 in AD.Conclusions:KLK6 deserves further investigations as a potential biomarker of Tau pathology in AD.
基金the National Key R&D Program of China (No.2017YFA0505200)the National Natural Science Foundation of China (Nos.21625104 and 21521091).
文摘Herein,we present a new strategy that for the first time achieved chemo- and enantio-selective hydrogenation of alkenes over arylhalides.Key to the success is that instead of using external poisons,we use the composition of the bimetallic nanocrystal catalysts to control chemoselectivity (hydrogenation of C=C bonds without cleavage of Ar-X bonds).We further show that this system combined with surface modifying chiral ligands can control the enantioselectivity.Thus,after synthesizing and screening a series of easily accessible MxAuy (M = Pd,Pt;x,y= 1,3,5) bimetallic nanocrystals (9-10 nm) supported on activated carbon,we identified that PtiAui/C is a recyclable and generally applicable catalyst for the chemoselective hydrogenation of alkenes without cleaving aryl halogen bonds.Furthermore,cinchonidine modified Pt,Aui/C is shown to be capable of enantioselective hydrogenation,as illustrated by the rapid and enantio-enriched synthesis of RIP1 inhibitor analogue 7-Br-O-Necl.
基金supported by National Key R&D Program of China(No.2018YFA0208602)NSFC(Nos.21622305,21873028,21703067)+1 种基金National Ten Thousand Talent Program for Young Top-notch Talents in ChinaShanghai ShuGuang project(No.17SG30)。
文摘Bimetallic nanoparticles(AmBn)usually exhibit rich catalytic chemistry and have drawn tremendous attention in heterogeneous catalysis.However,challenged by the huge configuration space,the understanding toward their composition and distribution of A/B element is known little at the atomic level,which hinders the rational synthesis.Herein,we develop an on-the-fly training strategy combing the machine learning model(SchNet)with the genetic algorithm(GA)search technique,which achieve the fast and accurate energy prediction of complex bimetallic clusters at the DFT level.Taking the 38-atom PtmAu38-mnanoparticle as example,the element distribution identification problem and the stability trend as a function of Pt/Au composition is quantitatively re solved.Specifically,results show that on the Pt-rich cluster Au atoms prefer to occupy the low-coordinated surface corner sites and form patch-like surface segregation patte rns,while for the Au-rich ones Pt atoms tend to site in the co re region and form the co re-shell(Pt@Au)configuration.The thermodynamically most stable PtmAu38-mcluster is Pt6 Au32,with all the core-region sites occupied by Pt,rationalized by the stronger Pt-Pt bond in comparison with Pt-Au and Au-Au bonds.This work exemplifies the potent application of rapid global sea rch enabled by machine learning in exploring the high-dimensional configuration space of bimetallic nanocatalysts.
基金supported by the Natural Science Foundation of Shaanxi Province(2020JZ-23)the Fundamental Research Funds for the Central Universities(GK201901002,GK202101005,2020CSLZ012 and 2019TS007)+4 种基金the Innovation Team Project for Graduate Student at Shaanxi Normal University(TD2020048Y)the Key Research and Development Program of Shaanxi(Program No.2020SF-355)the National Training Program of Innovation and Entrepreneurship for Undergraduates(S202010718130)the Open Foundation of Guangxi Key Laboratory of Processing for Non-ferrous Metals and Featured Materials at Guangxi University(2021GXYSOF02)the 111 Project(B14041)。
文摘Inefficient electrocatalysts and high-power consumption are two thorny problems for electrochemical hydrogen(H2)production from acidic water electrolysis.Herein we report the one-pot precise synthesis of ultrafine Au core-Pt Au alloy shell nanowires(Au@PtxAu UFNWs).Among them,Au@Pt_(0.077) Au UFNWs exhibit the best performance for formic acid oxidation reaction(FAOR)and hydrogen evolution reaction(HER),which only require applied potentials of 0.29 V and-22.6 m V to achieve a current density of 10 m A cm^(-2),respectively.The corresponding formic acid electrolyzer realizes the electrochemical H2 production at a voltage of only 0.51 V with 10 m A cm^(-2) current density.Density functional theory(DFT)calculations reveal that the Au-riched Pt Au alloy structure can facilitates the direct oxidation pathway of FAOR and consequently elevates the FAOR activity of Au@Pt_(0.077) Au UFNWs.This work provides meaningful insights into the electrochemical H_(2) production from both the construction of advanced bifunctional electrocatalysts and the replacement of OER.
文摘OBJECTIVE Currently, almost all chemical compounds or biological reagents to reverse or slow down the AD process have failed in clinical trials. An integrative and multi-targeted strategy is increasingly appreciated to effectively combat this devastating disease. Traditional Chinese medicine(TCM) has been widely used for treatment of dementia, and thus the advantages of the potential therapeutic features of TCM treatment and associated mechanisms should be well taken. The Amnesia Remedy Formula(ARF) was invented by one of the most influential Master of TCM SUN Si-miao, who lived for about 100 year old. The aim of this research is to characterize the time course changes of the cognitive behaviors post a ARF, and the mechanism underlying the effects, focusing on PKA-centered signaling for both enhancement of neural plasticity and clearance of the phosphorylated Tau. RESULTS We tested the efficacy of ARF on two animal models of AD, and examine the central role of PKA signaling in the enhancement of neural plasticity via PKA/CREB/BDNF pathway as well as clearance of toxic p Tau via PKA/GSK3β/p Tau pathway. In the scopolamine model, ARF effectively reversed the memory in Morris water maze(MWM) test, with some features superior to anti-AD drug donepezil. In a battery test of MWM, novel object recognition or T maze in 5-month-old senescenceaccelerated mouse prone 8(SAMP8) strain mice, two weeks of administration of ARF showed overall better improvement in memory loss than donepezil, and the effect lasted for at least 1 week after termination of administration of the formula. ARF increased expression of PKA/CREB/BDNF and synaptic proteins PSD95 expression, as well as enhanced Ser9 phosphorylation of GSK3β, thus reduced p Tau in the hippocampus. Blockade of PKA signaling blunted the anti-AD-like effect of ARF, with reversal of CREB/BDNF signaling. Transcriptomic analysis indicated some changes of novel molecules along this pathway may be part of the pathological and therapeutic mechanism, which warrants further investig
