Hydrogen Uptake and Release in Carbon Nanotube Electrocatalysts

Abstract

The recent technique of molecular beam-thermal desorption spectrometry was used here for monitoring hydrogen uptake and release from carbon nanotube networks, after electrochemical hydrogen uptake. This way, an accurate determination of the hydrogen mass absorbed in electrodes made from those assemblies can be achieved by significantly improving the signal-to-noise ratio. The hydrogen desorption mass spectra account for the enhanced surface capability for hydrogen adsorption in the electrodes and enable a comparison with the performance of a palladium electrode in similar conditions. A comparative study involving different carbon nanotube electrodes, in similar hydrogen uptake/desorption conditions, clearly confirmed the expectations about their enhanced hydrogen storage capacity and points to the great potential of carbon nanotube assemblies in replacing the heavier metal alloys as electrocatalysts.

Hydrogen Flow Controller Applied to Driving Behavior Observation of Hydrogen Fuel Cell Performance Test

“…The dynamic flow controller automatically adjusted the hydrogen flow rate to meet the right stoichiometry; nevertheless, the static flow controller constantly fed hydrogen into the fuel cell leading to excess hydrogen occurring in the system. The excess hydrogen was adsorbed on the activated carbon support surfaces in terms of physisorption. , Unfortunately, at 80 °C of the operating temperature in PEMFC, hydrogen cannot be desorbed from the carbon support porous surfaces, since the desorption process will occur at approximately 175 °C . This phenomenon history caused the reduction in the electrochemically active surface areas (ECSAs) of a catalyst layer and the decrease in electrical conductivity of carbon support particles.…”

“…The excess hydrogen was adsorbed on the activated carbon support surfaces in terms of physisorption. 37 , 38 Unfortunately, at 80 °C of the operating temperature in PEMFC, hydrogen cannot be desorbed from the carbon support porous surfaces, since the desorption process will occur at approximately 175 °C. 39 This phenomenon history caused the reduction in the electrochemically active surface areas (ECSAs) of a catalyst layer and the decrease in electrical conductivity of carbon support particles.…”

Hydrogen Storage Mechanism in Sodium-Based Graphene Nanoflakes: A Density Functional Theory Study

“…The establishment of appropriate transportation methods is an important factor when socially implementing hydrogen energy [13,14]. Carbon materials can safely store hydrogen [15,16]; in particular, lithium (Li)-doped graphene and carbon nanotubes (CNTs) have been used as effective storage materials [17,18]. Unfortunately, lithium is expensive because it is generally shipped from various international locations to China for processing into various products; therefore, alternative metals are required to realize a hydrogen-based society.…”