The effect of hydrothermal treatment time and level of carbon coating on the performance of PtRu/C catalysts in a direct methanol fuel cell

Abstract

A carbon-riveted PtRu/C catalyst of high stability has been prepared by in situ glucose carbonization using a hydrothermal method (GICH). Its mode of action and its practical application have been investigated by Xray diffraction, high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, a single-fuel cell test, and by conventional electrochemical measurements. The single-fuel cell test has demonstrated that the GICH hydrothermal method has high applicational usefulness. After 100 h the maximum power density of a single cell using carbon-riveted PtRu/C as anode catalyst fell by only 12.0%, from 76.6 to 67.4 mW cm À2 , compared with 28.4%, from 73.2 to 52.4 mW cm À2 , for traditionally prepared PtRu/C. In addition, when the optimal hydrothermal treatment time was 4 h and the level of carbon coating was 9%, a carbon-riveted PtRu/C catalyst with a 3.5 nm carbon coating gave the best stability, with similar initial activity to traditionally prepared PtRu/C. The significantly increased stability of carbon-riveted PtRu/C may be attributed to two factors: (1) the anchoring effect of the carbon nanolayer formed during in situ glucose carbonization by the hydrothermal method; and (2) the increased content of Pt(0), Ru(0), sp 3 -hybridized carbon and the C-OR group composition, and the clear decrease in PtO 2and RuO x H y following the carbon-riveting procedure.

Graphitic-C3N4 quantum dots modified carbon nanotubes as a novel support material for a low Pt loading fuel cell catalyst

“…† In addition, the tting methods for the elements are in accordance with our previous study. 35,46 The surface elemental compositions of all the catalysts are calculated in Table 2. Comparing the as-prepared PtRu/CNT and PtRu/T-CNT samples, the surface atomic Pt/Ru ratio of the PtRu/ CNT-QDs was close to 1 : 1 leading a higher activity towards the electro-catalytic oxidation of methanol.…”

Low Humidifying Proton Exchange Membrane Fuel Cells with Enhanced Power and Pt–C–h-SiO2 Anodes Prepared by Electrophoretic Deposition

“…Researchers in the field of proton exchange membrane fuel cells (PEMFCs) have been working toward boosting power density, cost-efficiency, and durability, taking a range of approaches to promote the cell performance. − In particular, anode and cathode catalysts capable of improving the efficiency of the hydrogen-oxidation reaction (HOR) and oxygen-reduction reaction (ORR) have attracted considerable attention. − Instead of attempting to improve the catalytic efficiency, most practical measures and strategies aim to minimize the overall weight, volume, and cost of the cell system. Although removing the water management system is one of the most effective ways of reducing the weight and volume, it would also deprive the functionalities of the Nafion electrolyte and electrocatalyst. − A low humidifying membrane–electrolyte assembly (MEA) provides a viable alternative by facilitating the transport of the moisture generated on the cathode side to the entire MEA.…”

Hydrothermally Deposited Carbon Coatings for Li-Ion Battery Active Materials

“…Hydrothermal carbonization (HTC) is another method of coating particles with carbon that has been utilized for nanoparticle coatings, 4,5 for catalysts and catalyst supports, 6,7 and in the synthesis of functional mesoporous and hollow carbon materials. 8 The hydrothermally reduced carbon (hydrochar) itself has been utilized as activated carbon, in water treatment, and as solid-fuel.…”