Experimental findings in support of atomic transport of hydrogen in silica

Data supporting a view of both molecular and atomic transport of hydrogen in quartz is presented. By studying isotopic equilibration, it is shown that virtually all of the molecules diffusing through a 1.5 mm thick quartz membrane at 900 degreesC have undergone dissociation. The catalytic properties of platinum for the dissociation of H-2 are used to increase the surface concentration of atomic hydrogen on a quartz membrane. It is found that the high surface concentration increases the total flux of hydrogen through the membrane. It is also found by comparison with literature data that diatomic molecules probably diffuse in two modes in quartz. We suggest that these two modes are one atomic and one molecular. (C) 2003 American Institute of Physics.