Ultraporous Palladium Supported on Graphene‐Coated Carbon Fiber Paper as a Highly Active Catalyst Electrode for the Oxidation of Methanol

Abstract

Ultraporous Pd nanocrystals for electrocatalysis applications were fabricated using a direct electrodeposition method on three differing carbon supports: flexible carbon fiber paper (CFP), and CFP modified with either graphene oxide nanosheets or their chemically reduced forms using a simple spray coating technique. The electrocatalytic activity of these electrodes was investigated for the direct electro‐oxidation reaction of methanol in alkaline media. Pd deposited on the CFP modified with reduced graphene oxide (rGO) has excellent poisoning tolerance to carbonaceous species and a significantly better catalytic activity toward methanol oxidation than the other two catalyst support materials. Pd/rGO/CFP in 2.0 M CH3OH in 2.0 M NaOH yields a specific current density of 241 mAmg–1 cm–2 determined at the anodic oxidation peak. It is believed that the collaborative effects due to the three‐dimensional ultraporous Pd nanocrystals and fast electron transfer owing to high conductivity of rGO nanosheets play an important role in enhancing the catalytic performance of Pd/rGO/CFP toward methanol oxidation in alkali media.

Graphene supported heterogeneous catalysts: An overview

“…One of the important characteristics of heterogeneous catalyst is its ability to be removed from the reaction conditions and recycled for the next reactions till the catalytic performance is sufficiently deactivated [211e213]. The Pd/ graphene catalyst system could be recycled with almost eight times of cycling, with the activity of the catalyst only dropping to 62% of conversion after the ninth cycle [206]. It has been recorded that Pd/graphene has no separation problems for hydrogenation, hydrogenolysis, and even carbonecarbon formation [214e216].…”

High-Performance Supercapacitor of Functionalized Carbon Fiber Paper with High Surface Ionic and Bulk Electronic Conductivity: Effect of Organic Functional Groups

“…On the other hand, carbon-based current collector such as CFP is rather stable in all electrolytes [9][10][11][12][13]. CFP has many advantages suitably to be used as the conductive substrate or current collector including high flexibility, corrosive resistance, porosity, and conductivity.…”

“…However, CFP consisting of sp 2 carbon fiber (90-95 wt.%) and adhesive material PTFE (5-10 wt.%) can be used only as a conductive current collector since it cannot store charge and its hydrophobic surface in nature, which cannot adsorb/absorb the aqueous electrolyte. CFP is therefore used as the conductive substrate and/or current collectors of the supercapacitors and fuel cells [9][10][11][12][13].…”

Highly Efficient Fuel Cell Electrodes from Few-Layer Graphene Sheets and Electrochemically Deposited Palladium Nanoparticles

“…The backward anodic peak in turn can then be attributed to the stripping of the poisoning intermediate. 14…”

“…In 2013 Sawangphruk et al designed a system consisting of an ultra-porous arrangement of Pd nanocrystals, electrochemically deposited on reduced graphene oxide and carbon fiber paper (Pd/rGO/CFP). Using a 0.5 M sodium hydroxide + 1 M ethanol solution they reached a catalyst activity of up to 1033 mA/(mg Pd), 14 which corresponds to a current density of 413.2 mA/cm². Albeit the shown systems and their reached values are not plenary comparable because of different experimental parameters, they show some contributing factors for a powerful EOR system.…”