Boosting Fuel Cell Performance with a Semiconductor Photocatalyst:  TiO₂/Pt−Ru Hybrid Catalyst for Methanol Oxidation

Abstract

A hybrid carbon fiber electrode (CFE) consisting of TiO2 semiconductor photocatalyst and Pt-Ru catalyst has been developed to boost the performance of direct methanol fuel cells (DMFC). These two catalyst nanoparticles are deposited on opposite sides of the carbon fiber paper such that methanol oxidation is carried out catalytically on Pt-Ru and photocatalytically on TiO2 under UV-light irradiation. Since both catalysts carry out methanol oxidation independently, we observe an additive effect in the current generation. The carbon support fibers provide a large network to collect the electrons from both of these catalytic processes and thus assist in efficient current generation. In addition, TiO2 improves the performance of the Pt-Ru catalyst in dark, indicating possible surface area improvement or diminished poisoning effects. The concept of incorporating a photocatalyst provides new ways to minimize precious metal content and enhance the performance of DMFCs. At low catalyst loadings (0.15 mg/cm2) at 295 K, a 25% enhancement in the peak power density is observed upon illumination with light.

Designing Photoelectrodes for Photocatalytic Fuel Cells and Elucidating the Effects of Organic Substrates

“…Ac omparison of the third and thirtieth scans for the TiO 2 electrode in the presence of formic acid, methanol, TEOA, and glucose did not show significantd ifference between the spectra,w hich thereby rules out any significant poisoning during repeatedc ycles. [41] The decrease in the absolute current density of TEOA with increasing scans (without peak shift) is ar esult of the mass-transfer limitation of the bulky molecule. The observation is consistent for all of the electrodes, that is, TiO 2 ,W O 3 ,a nd Nb 2 O 5 .Adecrease in the oxidative peak, accompanied by as hift of À0.…”

A facile approach to prepare silicon-based Pt-Ag tubular dendritic nano-forests (tDNFs) for solar-light-enhanced methanol oxidation reaction

“…In the past two decades, many bimetallic catalysts have been proposed to enhance the efficiency of MOR, including Pt-Ru [4], Pt-Ag [5], Pt-Au [6], etc. Recently, metal-oxide-supported Pt catalysts, including Pt-TiO2 [7], Pt-ZnO [8], and PtRu-TiO2 [9], were proposed to boost methanol oxidation under ultraviolet (UV) illumination for photo-electrochemical fuel cells [9]. Although over 60% of enhancement on MOR has been realized under UV illumination (365 nm, 100 W) [8], seldom, reports discussed the solar enhancement toward MOR, especially on pure metallic catalysts.…”

“…Traditionally, platinum (Pt)-based alloy has been used as common a catalyst in MOR. In the past two decades, many bimetallic catalysts have been proposed to enhance the efficiency , were proposed to boost methanol oxidation under ultraviolet (UV) illumination for photo-electrochemical fuel cells [9]. Although over 60% of enhancement on MOR has been realized under UV illumination (365 nm, 100 W) [8], seldom, reports discussed the solar enhancement toward MOR, especially on pure metallic catalysts.…”

Solvothermal synthesis and photocatalytic activity of S-doped TiO2 and TiS2 powders

“…A large number of efforts have been made to enhance the photocatalytic property of TiO 2 . For example, short band gap semiconductors CdS [1][2][3][4], CdSe [5], PbS [6], and Fe 2 O 3 [7], V 2 O 5 [8], Bi 2 S 3 [9], SnO 2 [10][11][12] have been used as additives, nitrogen [13] and sulfur [14] have been added to reduce the band gap energy of TiO 2 , and noble metals Pt-Ru [15] and Au [16,17] have been added as catalysts.…”