Direct formic acid fuel cells （DFAFCs） allow highly efficient low temperature conversion of chemical energy into electricity and are expected to play a vital role in our future sustainable society. However, the mass...Direct formic acid fuel cells （DFAFCs） allow highly efficient low temperature conversion of chemical energy into electricity and are expected to play a vital role in our future sustainable society. However, the massive precious metal usage in current membrane electrode assembly （MEA） technology greatly inhibits their actual applications. Here we demonstrate a new type of anode constructed by confining highly active nanoengineered catalysts into an ultra-thin catalyst layer with thickness around 100 nm. Specifically, an atomic layer of platinum is first deposited onto nanoporous gold （NPG） leaf to achieve high utilization of Pt and easy accessibility of both reactants and electrons to active sites. These NPG-Pt core/shell nanostructures are further decorated by a sub-monolayer of Bi to create highly active reaction sites for formic acid electro-oxidation. Thus obtained layer-structured NPG-Pt-Bi thin films allow a dramatic decrease in Pt usage down to 3 ~tg.cm-2, while maintaining very high electrode activity and power performance at sufficiently low overall precious metal loading. Moreover, these electrode materials show superior durability during half-year test in actual DFAFCs, with remarkable resistance to common impurities in formic acid, which together imply their great potential in applications in actual devices.展开更多
To improve the interfacial conductivity and corrosion resistance of AISI430 stainless steel(430 SS)as bipolar plates for direct formic acid fuel cells(DFAFCs),a Nb_(0.8)Zr_(0.2) layer has been successfully synthesized...To improve the interfacial conductivity and corrosion resistance of AISI430 stainless steel(430 SS)as bipolar plates for direct formic acid fuel cells(DFAFCs),a Nb_(0.8)Zr_(0.2) layer has been successfully synthesized via the pulsed laser deposition(PLD)technique on the surface of 430 SS.This Nb_(0.8)Zr_(0.2) layer is smooth,uniform,and comparatively compact without any surface flaw and micropore.Investigation under the simulated anodic environment of DFAFCs(0.05 M H_(2)SO_(4)+2 ppm HF+10 M HCOOH at 70℃)shows that the corrosion resistance of 430 SS is obviously ameliorated after the PLD modification.In addition,the interfacial contact resistance of Nb_(0.8)Zr_(0.2)-430 SS(6.0 mΩcm^(2))is much smaller than that of bare 430 SS(151.3 mΩcm^(2))at the clamping force of 140 N cm^(-2).Besides,diff erent from the highly increased interfacial contact resistance of bare 430 SS,the Nb_(0.8)Zr_(0.2)-430 SS shows a minor increase resistance after potentiostatic tests in simulated anodic environment of DFAFCs.展开更多
To design electrocatalysts with excellent performance, morphology, composition and structure is a decisive influential factor. In this work, ultrasmall Ag@Pd core-shell nanocrystals supported on Vulcan XC72R carbon wi...To design electrocatalysts with excellent performance, morphology, composition and structure is a decisive influential factor. In this work, ultrasmall Ag@Pd core-shell nanocrystals supported on Vulcan XC72R carbon with different Ag/Pd atomic ratios are synthesized via a facile successive reduction approach with formaldehyde and eth- ylene glycol as reducing agents, respectively. The Ag-core/Pd-shell nanostructures are revealed by high-resolution transmission electron microscopy （HRTEM）. Ag@Pd core-shell nanocrystals possess a narrow size distribution with an average size of ca. 4.3 nm. In comparison to monometallic Pd/C and commercial Pd black catalysts, such Ag@Pd core-shell nanocrystals display excellent electrocatalytic activities for formic acid oxidation, which may be due to high Pd utilization derived from the formation of Ag@Pd core-shell nanostructure and the strong interaction between Ag and Pd.展开更多
In pursuit of low-cost direct formic acid fuel cells,tungsten carbide(WC)supported Pd catalyst is considered as an ideal candidate for efficient decomposition of formic acid due to low Pd utilization and excellent per...In pursuit of low-cost direct formic acid fuel cells,tungsten carbide(WC)supported Pd catalyst is considered as an ideal candidate for efficient decomposition of formic acid due to low Pd utilization and excellent performance.Herein,different adsorption configurations and active sites of the intermediates,involved in the HCOOH decomposition,on WC(0001)-supported Pd monolayer(Pd/WC(0001))surface investigated by using density functional theory.The results reveal that trans-HCOOH,HCOO,cis-COOH,trans-COOH,HCO,CO,H2 O,OH and H exhibit chemisorption on Pd/WC(0001)surface,whereas cis-HCOOH and CO2 exhibit weak interactions with Pd/WC(0001)surface.In addition,the minimum energy pathways of HCOOH decomposition are analyzed to generate CO and CO2 due to the fracture of C–H,H–O and C–O bonds.The adsorbed HCOOH,HCOO,mH COO,cis-COOH and trans-COOH configurations exhibit dissociation rather than desorption.CO formation occurs through the decomposition of cis-COOH,trans-COOH and HCO,whereas the CO2 formation happens due to the decomposition of HCOO.It is found that the most favorable pathway for HCOOH decomposition on Pd/WC(0001)surface is HCOOH→HCOO→CO2,where the formation of CO2 from HCOO dehydrogenation determines the reaction rate.Overall,CO2 is the most dominant product of HCOOH decomposition on Pd/WC(0001)surface.The presence of WC,as monolayer Pd carrier,does not alter the catalytic behavior of Pd and significantly reduces the Pd utilization.展开更多
Nanocomposites with synergistic effect are of great interest for their enhanced properties in a given application. Herein, we reported the high catalytic activity of Pt-containing Ag2S-noble metal nanocomposites in fo...Nanocomposites with synergistic effect are of great interest for their enhanced properties in a given application. Herein, we reported the high catalytic activity of Pt-containing Ag2S-noble metal nanocomposites in formic acid oxidation, which is a key reaction in direct formic acid fuel cell. The electrochemical measurements including voltammograms and chronoamperograms are used to characterize the catalytic property of Pt-containing nanocomposites for the oxidation of formic acid. In view of the limited literatures on using nanocomposites consisting of semiconductor and noble metals for catalyzing the reactions of polymer electrolyte membrane-based fuel cells, this study provides a helpful exploration for expanding the application of semiconductor-noble metal nanocomposites.展开更多
文摘Direct formic acid fuel cells （DFAFCs） allow highly efficient low temperature conversion of chemical energy into electricity and are expected to play a vital role in our future sustainable society. However, the massive precious metal usage in current membrane electrode assembly （MEA） technology greatly inhibits their actual applications. Here we demonstrate a new type of anode constructed by confining highly active nanoengineered catalysts into an ultra-thin catalyst layer with thickness around 100 nm. Specifically, an atomic layer of platinum is first deposited onto nanoporous gold （NPG） leaf to achieve high utilization of Pt and easy accessibility of both reactants and electrons to active sites. These NPG-Pt core/shell nanostructures are further decorated by a sub-monolayer of Bi to create highly active reaction sites for formic acid electro-oxidation. Thus obtained layer-structured NPG-Pt-Bi thin films allow a dramatic decrease in Pt usage down to 3 ~tg.cm-2, while maintaining very high electrode activity and power performance at sufficiently low overall precious metal loading. Moreover, these electrode materials show superior durability during half-year test in actual DFAFCs, with remarkable resistance to common impurities in formic acid, which together imply their great potential in applications in actual devices.
基金financially supported by the National Natural Science Foundation of China(Nos.51962027,51974167,21968022,and 21868022)the Natural Science Foundation of Inner Mongolia(No.2019BS02002)+1 种基金the Project of Science Foundation of the Educational Department of Inner Mongolia(No.NJZY19135)the Inner Mongolia University of Science and Technology Innovation Fund(No.2019QDL-B23)。
文摘To improve the interfacial conductivity and corrosion resistance of AISI430 stainless steel(430 SS)as bipolar plates for direct formic acid fuel cells(DFAFCs),a Nb_(0.8)Zr_(0.2) layer has been successfully synthesized via the pulsed laser deposition(PLD)technique on the surface of 430 SS.This Nb_(0.8)Zr_(0.2) layer is smooth,uniform,and comparatively compact without any surface flaw and micropore.Investigation under the simulated anodic environment of DFAFCs(0.05 M H_(2)SO_(4)+2 ppm HF+10 M HCOOH at 70℃)shows that the corrosion resistance of 430 SS is obviously ameliorated after the PLD modification.In addition,the interfacial contact resistance of Nb_(0.8)Zr_(0.2)-430 SS(6.0 mΩcm^(2))is much smaller than that of bare 430 SS(151.3 mΩcm^(2))at the clamping force of 140 N cm^(-2).Besides,diff erent from the highly increased interfacial contact resistance of bare 430 SS,the Nb_(0.8)Zr_(0.2)-430 SS shows a minor increase resistance after potentiostatic tests in simulated anodic environment of DFAFCs.
基金We would like to thank the National Natural Science Foundation of China （21573025 and 51574047）, Natural Science Foundation of Jiangsu Province （BK20151183）, Foundation of Jiangsu Key Laboratory of Advanced Catalytic Materials and Technology （BM2012110）, Qing Lan Project, Foundation of Advanced Catalysis and Green Manufacturing Collaborative Innovation Center （ACGM2016-06-30） and the Project Funded by the Priority Academic Program Development （PAPD） of Jiangsu Higher Education Institutions for support of this work.
文摘To design electrocatalysts with excellent performance, morphology, composition and structure is a decisive influential factor. In this work, ultrasmall Ag@Pd core-shell nanocrystals supported on Vulcan XC72R carbon with different Ag/Pd atomic ratios are synthesized via a facile successive reduction approach with formaldehyde and eth- ylene glycol as reducing agents, respectively. The Ag-core/Pd-shell nanostructures are revealed by high-resolution transmission electron microscopy （HRTEM）. Ag@Pd core-shell nanocrystals possess a narrow size distribution with an average size of ca. 4.3 nm. In comparison to monometallic Pd/C and commercial Pd black catalysts, such Ag@Pd core-shell nanocrystals display excellent electrocatalytic activities for formic acid oxidation, which may be due to high Pd utilization derived from the formation of Ag@Pd core-shell nanostructure and the strong interaction between Ag and Pd.
基金supported by the National Natural Science Foundation of China(21776259)Key Laboratory of Micro-Nano Powder and Advanced Energy Materials of Anhui Higher Education Institutes,Chizhou University~~
文摘In pursuit of low-cost direct formic acid fuel cells,tungsten carbide(WC)supported Pd catalyst is considered as an ideal candidate for efficient decomposition of formic acid due to low Pd utilization and excellent performance.Herein,different adsorption configurations and active sites of the intermediates,involved in the HCOOH decomposition,on WC(0001)-supported Pd monolayer(Pd/WC(0001))surface investigated by using density functional theory.The results reveal that trans-HCOOH,HCOO,cis-COOH,trans-COOH,HCO,CO,H2 O,OH and H exhibit chemisorption on Pd/WC(0001)surface,whereas cis-HCOOH and CO2 exhibit weak interactions with Pd/WC(0001)surface.In addition,the minimum energy pathways of HCOOH decomposition are analyzed to generate CO and CO2 due to the fracture of C–H,H–O and C–O bonds.The adsorbed HCOOH,HCOO,mH COO,cis-COOH and trans-COOH configurations exhibit dissociation rather than desorption.CO formation occurs through the decomposition of cis-COOH,trans-COOH and HCO,whereas the CO2 formation happens due to the decomposition of HCOO.It is found that the most favorable pathway for HCOOH decomposition on Pd/WC(0001)surface is HCOOH→HCOO→CO2,where the formation of CO2 from HCOO dehydrogenation determines the reaction rate.Overall,CO2 is the most dominant product of HCOOH decomposition on Pd/WC(0001)surface.The presence of WC,as monolayer Pd carrier,does not alter the catalytic behavior of Pd and significantly reduces the Pd utilization.
基金Financial support from the 100 Talents Program of the Chinese Academy of Sciences, National Natural Science Foundation of China (No.: 21173226, 21376247)State Key Laboratory of Multiphase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences (MPCS-2011-D-08, MPCS-2010C-02)
文摘Nanocomposites with synergistic effect are of great interest for their enhanced properties in a given application. Herein, we reported the high catalytic activity of Pt-containing Ag2S-noble metal nanocomposites in formic acid oxidation, which is a key reaction in direct formic acid fuel cell. The electrochemical measurements including voltammograms and chronoamperograms are used to characterize the catalytic property of Pt-containing nanocomposites for the oxidation of formic acid. In view of the limited literatures on using nanocomposites consisting of semiconductor and noble metals for catalyzing the reactions of polymer electrolyte membrane-based fuel cells, this study provides a helpful exploration for expanding the application of semiconductor-noble metal nanocomposites.
