Trimetallic synergy in dendritic intermetallic PtSnBi nanoalloys for promoting electrocatalytic alcohol oxidation

Intermetallic Nanocrystals for Fuel-Cells-Based Electrocatalysis

Electrocatalysis underpins the renewable electrochemical conversions for sustainability, which further replies on metallic nanocrystals as vital electrocatalysts. Intermetallic nanocrystals have been known to show distinct properties compared to their disordered counterparts, and been long explored for functional improvements. Tremendous progresses have been made in the past few years, with notable trend of more precise engineering down to an atomic level and the investigation transferring into more practical membrane electrode assembly (MEA), which motivates this timely review. After addressing the basic thermodynamic and kinetic fundamentals, we discuss classic and latest synthetic strategies that enable not only the formation of intermetallic phase but also the rational control of other catalysis-determinant structural parameters, such as size and morphology. We also demonstrate the emerging intermetallic nanomaterials for potentially further advancement in energy electrocatalysis. Then, we discuss the state-of-the-art characterizations and representative intermetallic electrocatalysts with emphasis on oxygen reduction reaction evaluated in a MEA setup. We summarize this review by laying out existing challenges and offering perspective on future research directions toward practicing intermetallic electrocatalysts for energy conversions.

Hierarchical Pt-In Nanowires for Efficient Methanol Oxidation Electrocatalysis

Direct methanol fuel cells (DMFC) have attracted increasing research interest recently; however, their output performance is severely hindered by the sluggish kinetics of the methanol oxidation reaction (MOR) at the anode. Herein, unique hierarchical Pt-In NWs with uneven surface and abundant high-index facets are developed as efficient MOR electrocatalysts in acidic electrolytes. The developed hierarchical Pt₈₉In₁₁ NWs exhibit high MOR mass activity and specific activity of 1.42 A mg_Pt^-1 and 6.2 mA cm^-2, which are 5.2 and 14.4 times those of Pt/C, respectively, outperforming most of the reported MORs. In chronoamperometry tests, the hierarchical Pt₈₉In₁₁ NWs demonstrate a longer half-life time than Pt/C, suggesting the better CO tolerance of Pt₈₉In₁₁ NWs. After stability, the MOR activity can be recovered by cycling. XPS, CV measurement and CO stripping voltammetry measurements demonstrate that the outstanding catalytic activity may be attributed to the facile removal of CO due to the presence of In site-adsorbing hydroxyl species.

Synthesis of SDS-Modified Pt/Ti3C2Tx Nanocomposite Catalysts and Electrochemical Performance for Ethanol Oxidation

It is well-known that platinum (Pt) is still the preferred material of anode catalyst in ethanol oxidation, however, the prohibitive high cost and CO poisoning of Pt metal impede the commercialization of fuel cells. Therefore, improving the utilization rate of catalysts and reduce the cost of catalyst become one of the most concerned focus in the construction of fuel cells. In this work, the Pt-based catalysts are synthesized by using different content of sodium dodecyl sulfate (SDS) modified-Ti₃C₂T_x support, and the dispersion regulation function of SDS modified-Ti₃C₂T_x supported on Pt nanoparticles is investigated. The structure, composition and morphology of different catalysts are characterized by X-ray diffraction (XRD), X-ray spectroscopy (EDX), transmission electron microscopy (TEM) and high-resolution TEM, respectively. It is found that the Pt nanoparticles in pure Ti₃C₂T_x surface are serious aggregated and show poor dispersion, whereas the Pt nanoparticles in SDS modified-Ti₃C₂T_x have a better dispersion. The electrochemical results revealed that SDS modified-Ti₃C₂T_x supported Pt nanoparticles has higher electrocatalytic activity and stability in both acidic and alkaline ethanol oxidation when the dosage of SDS increases to 100 mg. These findings indicate that the SDS-Ti₃C₂T_x/Pt catalysts show a promising future of potential applications in fuel cells with modification of Ti₃C₂T_x support.