Platinum and Palladium Nano-Structured Catalysts for Polymer Electrolyte Fuel Cells and Direct Methanol Fuel Cells

Abstract

In this review, we present the synthesis and characterization of Pt, Pd, Pt based bimetallic and multi-metallic nanoparticles with mixture, alloy and core-shell structure for nano-catalysis, energy conversion, and fuel cells. Here, Pt and Pd nanoparticles with modified nanostructures can be controllably synthesized via chemistry and physics for their uses as electro-catalysts. The cheap base metal catalysts can be studied in the relationship of crystal structure, size, morphology, shape, and composition for new catalysts with low cost. Thus, Pt based alloy and core-shell catalysts can be prepared with the thin Pt and Pt-Pd shell, which are proposed in low and high temperature proton exchange membrane fuel cells (PEMFCs), and direct methanol fuel cells (DMFCs). We also present the survey of the preparation of Pt and Pd based catalysts for the better catalytic activity, high durability, and stability. The structural transformations, quantum-size effects, and characterization of Pt and Pd based catalysts in the size ranges of 30 nm (1-30 nm) are presented in electro-catalysis. In the size range of 10 nm (1-10 nm), the pure Pt catalyst shows very large surface area for electro-catalysis. To achieve homogeneous size distribution, the shaped synthesis of the polyhedral Pt nanoparticles is presented. The new concept of shaping specific shapes and morphologies in the entire nano-scale from nano to micro, such as polyhedral, cube, octahedra, tetrahedra, bar, rod, and others of the nanoparticles is proposed, especially for noble and cheap metals. The uniform Pt based nanosystems of surface structure, internal structure, shape, and morphology in the nanosized ranges are very crucial to next fuel cells. Finally, the modifications of Pt and Pd based catalysts of alloy, core-shell, and mixture structures lead to find high catalytic activity, durability, and stability for nano-catalysis, energy conversion, fuel cells, especially the next large-scale commercialization of next PEMFCs, and DMFCs.

Iron Oxide Nanoparticles for Next Generation Gas Sensors

“…In rapid and efficient manners, scholars' focus will be on Fe-or Pt-based nanoparticles for practical application in gas sensors for the detection of toxic gases in the environment such as CO, NO x , and SO x . However, the various types of nanoparticles can be also exploited in other applications for energy conversion, high-performance batteries [31,32,70], low temperature fuel cells (FCs), [33][34][35][36] contrast agents for magnetic resonance imaging (MRI) [37,38]. The synthesis approach followed polyol chemical method to make Pt-and Fe-based particles with various structures of grains and grain boundaries, which researchers have successfully developed in recent years [39][40][41][42].…”

“…Around the world, so far researchers have synthesized metal nanoparticles by chemical and physical methods, such as Cu, Ag, Au, Pt (Figure 2a) [33][34][35][36]81], Pd, Ru, Rh, Ir, Os, Ni, Fe, and Co, respectively. In major strategies, they can be supported on Fe or Sn oxides, e.g.…”

“…In the recent highlights, we have successfully synthesized Fe, Pt, Pd, and Rh nanoparticles in the 10 nm range by polyol method with the small additions of some inorganic salts [28,29,[33][34][35][36][37]42]. Thus, the structural transformations, the highest quantum-size effect, and the characterization of Fe-, Pt-, and Pd-based catalysts in the size range of 30 nm are of importance in sensing properties, and catalytic activity in electro-catalysis.…”

“…In new Fe oxide based micro/nanoscale materials, it can also lead to better predict an improvement of high-performance energy conversion and storage of battery, potential biomedical applications [79,83] in the efficient treatments of dangerous tumors and cancers as well as potential applications of photocatalyst and chemical sensors [70,79,[83][84][85][86]. In his main contributions [26][27][28][29][33][34][35][36][39][40][41][42][78][79][80][81][82][83]87,88], Dr Nguyen and co-workers have developed the new definitions and concepts of self-attachment, elastic and inelastic self-collision, self-aggregation, and self-assembly phenomena of the nanoparticles according to chemical synthetic processes [78,94], and the very complex issues of atomic arrangements in order or disorder inside metal, bimetal, and alloy nanoparticles with defects, stacking fault, dislocation, twin planes etc at 10 nm by HRTEM/STEM methods [36,42]. In addition, the critical roles of heat treatment to the prepared particle products led to particle deformation, i.e.…”

Fabrication of hollow platinum–ruthenium core–shell catalysts with nanochannels and enhanced performance for methanol oxidation

“…Besides, it is well recognized that the electrocatalytic properties are strongly dependent on the size, structure, morphology of the nanocatalysts [11,12]. Among various nanostructures, the nanoporous catalysts with large specific area, nanochannels, nanometer-scale pores and highly ordered networks, have attracted much attention for years [13].…”