The surface of metal oxide nanoparticles are typically coated with layers of water that are strongly bonded to the surface. The properties of these water layers are significantly different from that of bulk water, and play a major role in the chemistry of the surfaces. As part of a program of understanding that chemistry , involving QENS, INS, NMR and ab initio simulations, we propose to measure the momentum distribution of the protons as a function of number of layers of water. We will study two different metals, Ti and Sn, with dramatically different transport properties for protons on the surface.