Neutron Scattering Methodology for Absolute Measurement of Room-Temperature Hydrogen Storage Capacity and Evidence for Spillover Effect in a Pt-Doped Activated Carbon

A neutron scattering methodology is proposed to simultaneously determine the total hydrogen adsorption, the excess hydrogen adsorption, and hydrogen gas confined in the porous sample. This method is capable of an absolute measurement of the hydrogen content without need for any calibration. It involves the least amount of corrections and is not likely to be affected by the instrumental factors compared to the traditional gravimetric and volumetric methods. We used this method to study the physisorption behavior at room temperature (RT) of a Pt-doped activated carbon sample as a function of hydrogen pressure. This method will become a simple and important tool for solving various problems arising from the traditional measurements of RT hydrogen storage capacities. It can be combined with an in situ small-angle neutron scattering to study the hydrogen spillover effect in the kinetic adsorption process. Storage capacity and spatial distribution of the hydrogen adsorbed due to spillover are concurrently revealed.