Synthesis and Characterization of Three-Dimensionally Ordered Macroporous (3DOM) Tungsten Carbide: Application to Direct Methanol Fuel Cells

Abstract

Three-dimensionally ordered macroporous tungsten carbide (3DOM WC) with varying pore size was synthesized using the “inverse-opal” method. Poly{methyl methacrylate} (PMMA) colloidal crystal template with sphere diameters ranging from 180 to 490 nm was used. Two synthesis procedures were performed, the first requiring calcination of tungsten impregnated PMMA colloidal template in air followed by carburization in H2/CH4/N2 atmosphere. The second procedure involved direct carburization of the tungsten impregnated template without prior calcination. The effect of Pt-modification of the template prior to carburization on the resulting material composition was also investigated. The material properties were evaluated using surface and bulk characterization techniques. Finally, cyclic voltammetry was used to investigate the methanol electro-oxidation activity of the 3DOM WC and Pt-modified 3DOM WC in acidic electrochemical environment.

A colloidoscope of colloid-based porous materials and their uses

“…One of the primary reasons hierarchical CBPM are used as electrodes is their high surface area, with a higher active area for a given volume of material. High surface area allows for easy access to active materials in batteries 75,421,423,426,[428][429][430][431] and fuel cells, 432,433 improving energy density. It also leads to higher dye loading, and thus increased light absorption and higher rates, in dye-sensitized solar cells.…”

“…430 Ordered, inverse structures have been particularly well investigated as a means of controlling ion transport, for example in Li-ion batteries, 26,428,466 Li-air batteries, 431 dye-sensitized solar cells (DSSC), 450 and fuel cells. 432,433 These colloid-templated structures have also been used as separators in batteries 184 and fuel cells 434 due to their ability to control ion diffusion. Capacitors also benefit from the control over diffusion, because high surface area increases the capacitance, but it can also cause very high charging times.…”

Novel Synthesis of Hierarchical Tungsten Carbide Micro‐/Nanocrystals from a Single‐Source Precursor

“…WC has been extensively applied in cutting and drilling tools, wear‐resistant parts of machines, and hard alloy coatings 2 . WC nanocrystals are also widely used as catalysts or catalyst supports, because of their platinum‐like behavior in surface catalysis 3,4 …”

Cluster‐Mediated Crossed Bilayer Precision Assemblies of 1D Nanowires

“…At low cluster concentrations, the NW surface is accessible to all the QCs, which attach uniformly to it (on equivalent highest energy sites) leading to a large change in peak positions. But as the cluster concentration increases, adsorption over the available lower energy sites as well as multilayers becomes possible, Self-organization of micro and nanostructures leading to superlattices enabling the creation of photonic crystals, [1][2][3][4][5] sensors, [6][7][8] materials for biomimetics, [ 9 ] energy harvesting, [ 10,11 ] and high-density storage, [12][13][14] is known for some time. Such self-assemblies in 2D and 3D are formed in homogeneous liquids and at liquid-vapor/gas or liquid-liquid interfaces with single or multiple phases.…”