Enhanced low-humidity performance of proton exchange membrane fuel cell by incorporating phosphoric acid-loaded covalent organic framework in anode catalyst layer

Developing self-humidifying membrane electrode assembly (MEA) is of great significance for the practical use of proton exchange membrane fuel cell (PEMFC). In this work, a phosphoric acid (PA)-loaded Schiff base networks (SNW)-type covalent organic framework (COF) is proposed as the anode catalyst layer (CL) additive to enhance the PEMFC performance under low humidity conditions. The unique polymer structure and immobilized PA endow the proposed COF network with not only excellent water retention capacity but also proton transfer ability, thus leading to the superior low humidity performance of the PEMFC. The optimization of the additive content, the effect of relative humidity (RH) and PEMFC operating temperature are investigated by means of electrochemical characterization and single cell test. At a normal operation temperature of 60 °C and 38% RH, the MEA with optimized COF content (10 wt%) showes the maximum power density of 582 mW cm−2, which is almost 7 times higher than that of the routine MEA (85 mW cm−2)

Applicability of analytical protocols for the characterisation of carbon-supported platinum group metal fuel cell electrocatalysts

The nanoparticulate size of fuel cell electrocatalysts raises significant challenges in the analytical techniques used in their structural and electrochemical characterisation. For this reason, the applicability of analytical protocols in the qualitative and quantitative characterisation of nanophase fuel cell electrocatalysts was investigated. A set of structural and chemical properties influencing the performance of the electrocatalysts was identified. A large range of analytical tools was employed in characterising the electrocatalysts of interest. High accuracy and precision in the quantitative and qualitative structural and electrochemical characterisation of Pt/C and Pt-Ru/C nanophase electrocatalysts was demonstrated. Certain techniques were deemed to be highly applicable in discriminating between high- and low-performance electrocatalysts based on their structural and electrochemical properties. The goal of this effort is to contribute to the development of South Africa's capabilities in the emerging hydrogen economy

Carbon-nanostructured materials for energy generation and storage applications

We have developed and refined a chemical vapour deposition method to synthesise nanotubes using liquid petroleum gasasthe carbonsource. The nanotubes were thoroughly characterised by scanning electron microscopy, transmission electron microscopyX-ray diffraction and thermogravimetric analysis. The protocol to grow nanotubes was then adapted to deposit nanotubes on the surface of different substrates, which were chosen based upon howthe substrates could be applied in various hydrogen energyconver-sion systems. Carbon nanotubes area nanostructured material with an extremely wide range of application sinvariousenergy applications. The methods outlined demonstrate the completedevelopment of carbon nanotube composite materials with direct applications in hydrogen energy generation, storage and conversion