Pt-Te alloy nanowires towards formic acid electrooxidation reaction

The high-performance anodic electrocatalysts is pivotal for realizing the commercial application of the direct formic acid fuel cells.In this work,a simple polyethyleneimine-assisted galvanic replacement reaction is applied to synthesize the high-quality PtTe alloy nanowires(PtTe NW)by using Te NW as an efficient sacrificial template.The existence of Te atoms separates the continuous Pt atoms,triggering a direct reaction pathway of formic acid electrooxidation reaction(FAEOR)at PtTe NW.The one-dimensional architecture and highly active sites have enabled PtTe NW to reveal outstanding electrocatalytic activity towards FAEOR with the mass/specific activities of 1091.25 mA mg^(-1)/45.34 A m^(-2)at 0.643 V potential,which are 44.72/23.16 and 20.26/11.75 times bigger than those of the commercial Pt and Pd nanoparticles,respectively.Density functional theory calculations reveal that Te atoms optimize the electronic structure of Pt atoms,which decreases the adsorption capacity of CO intermediate and simultaneously improves the durability of PtTe NW towards FAEOR.This work provides the valuable insights into the synthesis and design of efficient Pt-based alloy FAEOR electrocatalysts.

Formic acid electro-oxidation:Mechanism and electrocatalysts design

As a model reaction for the electrooxidation of many small organic molecules,formic acid electrooxidation(FAEO)has aroused wide concern.The promises of direct formic acid fuel cells(DFAFC)in application further strengthen people’s attention to the related research.However,despite decades of study,the FAEO mechanism is still under debate due to the multi-electron and multi-pathway nature of the catalytic process.In this review,the progresses towards understanding the FAEO mechanism along with the developed methodology(electrochemistry,in-situ spectroscopy,and theoretical calculation and simulation)are summarized.We especially focused on the construction of anti-poisoning catalysts system based on understanding of the catalytic mechanism,with anti-poisoning catalyst design being systemically summarized.Finally,we provide a brief summarization for current challenges and future prospects towards FAEO study.

Platinum-Tellurium Alloy Metallene Toward Formic Acid Oxidation Reaction

Engineering the composition and/or morphology of noble metal nanocrystals is a highly effective strategy for enhancing their electrocatalytic performance.Recently,metallenes with specific chemical and physical properties have increasingly attracted attention in the field of electrocatalysis.In this work,two-dimensional ultrathin platinum-tellurium alloy metallene(PtTe A-ML)is synthesized using a conventional liquid-phase chemical reduction method.The high atomic utilization as well as alloy effect endow PtTe A-ML with preeminent electrocatalytic activity for the formic acid oxidation reaction(FAOR).Specifically,the direct oxidation pathway of FAOR can be completely achieved using PtTe A-ML,which suppresses the production of toxic carbon monoxide(CO)intermediates and improves the reaction kinetics of FAOR.Accordingly,the FAOR activity of PtTe AML in acidic media is 43 and 5.6 times higher than that of commercial Pt and Pd nanocrystals,respectively.Meanwhile,PtTe A-ML also exhibits excellent electrocatalytic activity for the CO oxidation reaction because of the introduction of oxygenophilic Te atoms and electron transfer between Pt and Te,which elevates the durability of PtTe A-ML for FAOR.This study provides a simple synthesis strategy for PtTe A-ML and demonstrates that PtTe A-ML has a promising practical prospect for direct formic acid fuel cells.

Facile synthesis of PdCu nanocluster-assembled granular films as highly efficient electrocatalysts for formic acid oxidation

Developing efficient and stable bimetallic Pdbased anode electrocatalysts toward formic acid oxidation(FAO)is of great significance for commercial applications of direct formic acid fuel cells(DFAFCs).Herein,we report a facile synthesis approach to fabricate PdCu nanoclusters(NCs)catalysts with granular-film structure.The introduction of Cu can adjust the electronic structure and d-band center of Pd,which can improve the catalytic performance of the catalysts.Compared with Pd NCs catalyst,the catalytic durability and activity of PdCu NCs catalysts for FAO are greatly improved.The order for catalytic activity of NC metals is Pd_(85)Cu_(15)NCs>Pd_(70)Cu_(30)NCs>Pd NCs.The maximum mass activity can be acquired with the Pd_(85)Cu_(15)NCs catalyst,which is about1.7 times that of the Pd NCs catalyst.And Pd_(85)Cu_(15)NCs catalyst still maintains the highest catalytic current density after 50 cycles,indicating that Pd_(85)Cu_(15)NCs catalyst has the best durability and electrocatalytic activity for FAO.Our work provides a new prospect for the design of highly efficient anode catalysts materials for DFAFCs.

Facile Synthesis of Carbon-Supported Ultrasmall Ag@Pd Core-Shell Nanocrystals with Superior Electrocatalytic Activity for Direct Formic Acid Fuel Cell Application

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.