Progress in Developments of Inorganic Nanocatalysts for Application in Direct Methanol Fuel Cells

Abstract

Significant progress has been made in the last few years toward synthesizing highly dispersible inorganic catalysts for application in the electrodes of direct methanol fuel cells. In addition, research toward achieving an efficient catalyst supporting matrix has also attracted much attention in recent years. Carbon black-(Vulcan XC-72) supported Platinum and PlatinumRuthenium catalysts have for long served as the conventional choice as the cathode and the anode catalyst materials, respectively. Oxygen reduction reaction at the cathode and methanol oxidation reaction at the anode occur simultaneously during the operation of a direct methanol fuel cell. However, inefficiencies in these reactions result in a generation of mixed potential. This, in turn, gives rise to reduced cell voltage, increased oxygen stoichiometric ratio, and generation of additional water that is responsible for water flooding in the cathode chamber. In addition, the lack of long-term stability of Pt-Ru anode catalyst, coupled with the tendency of Ru to cross through the polymer electrolyte membrane and eventually get deposited on the cathode, is also a serious drawback. Another source of potential concern is the fact that the natural resource of Pt and the rare earth metal Ru is very limited, and has been predicted to become exhausted very soon. To overcome these problems, new catalyst systems with high methanol tolerance and higher catalytic activity than Pt need to be developed. In addition, the catalyst-supporting matrix is also witnessing a change from traditionally used carbon powder to transition metal carbides and other highperformance materials. This article surveys the recent literature based on the advancements made in the field of highly dispersible inorganic catalysts for application in direct methanol fuel cells, as well as the progress made in the area of catalyst-supporting matrices.

Synthesis, Preparation, and Performance of Blends and Composites of π-Conjugated Polymers and their Copolymers in DMFCs

“…In addition, modification of the base p-CP structure by incorporating suitable functional groups (such as sulfonic acid group) can result in increasing the interaction efficiency between the matrix and the catalyst metal particles, as well as the proton conductivity of the PEM. 14,19,20,[187][188][189] Furthermore, use of p-CP nanofibers, nanotubes, nanowires, nanowhiskers, etc., hold the key to achieve higher performance, and the current status of nanomaterials research is huge enough to supply the raw materials and necessary technological supports for DMFC device fabrication. …”

The role of surface spin polarization on ceria-supported Pt nanoparticles

“…The weakening can be understood from Mulliken spin population analysis in the SP system. The strong CO adsorption on Pt 19 , due to the π-back bonding between Pt and CO 80 , can reduce the donation of Pt's valence electron to surface oxygen. As a result, the pairing electrons on Pt atoms decreases the net spin moment on the Pt 19 (see Figure 3c-d).…”

Nanorods of cerium oxide as an improved electrocatalyst for enhanced oxygen reduction in single-chambered microbial biofuel cells

“…This, in turn, results in loss of potential at the cathode, leading to generation of low current and power outputs [18]. Moreover, Pt is a high-cost noble metal with limited availability [19][20][21], which seriously questions the commercial viability of MBFCs using Pt electrocatalysts [13]. Therefore, there is a critical need to find a more efficient and lower cost alternative material that can replace the traditionally used Pt metal as the ORR catalyst in MBFCs.…”