Hydrogen adsorption on platinum doped activated carbon

Abstract

Hydrogen energy system is expected to progressively replace the existing fossil fuels in the future. In particular, one potential use of hydrogen lies in powering zeroemission vehicles via a proton exchange membrane fuel cell (PEMFC). However, to make the PEMFC works on a vehicle, hydrogen storage is one of the critical components. When hydrogen is used on the vehicle, the equipment must has a high storage capacity. Carbon with high porosity and surface area as well as with the presence of metal loading were expected to obtain the maximum hydrogen adsorption via spillover effect on activated carbon (AC). The main objective of this research is to investigate the hydrogen adsorption on AC and platinum (Pt)-doped AC samples with different pressures (150, 250 and 350 psig). A comparative characterization was carried out using field emission scanning electron microscopy, x-ray diffraction and nitrogen adsorption isotherm analysis. It was shown that the presence of Pt metal reduced the surface area of AC from 675.32 m2.g-1 to 638.65 m2.g-1. Hydrogen adsorption at 150, 250 and 350 psig at room temperature exhibited two distinct behaviours. At 150 psig, the textural properties are critical and the adsorption capacities slightly increased with the Pt loading. On the contrary, at the higher pressure, the contribution of Pt nanoparticles was positive and marked by increased amounts of hydrogen reversibly adsorb from 0.7 to 0.9 wt.%. However, the amount of hydrogen uptake for Pt-doped AC was slightly lower compared to AC. AC adsorbed 1.07 wt.% of hydrogen at 350 psig compared to 0.9 wt.% for 10 wt.% Pt-doped AC. These findings have significant implications for the hydrogen storage in carbon-based materials, and further study needs to be done to enhance hydrogen uptake for Pt-doped AC.