Rutherford Backscattering, Low-energy ion scattering spectroscopy (LEIS), Mid-energy ion scattering spectroscopy (MEIS) might work to detect H. What is your coating thickness?

Is there a reason you cannot use ion beam techniques? One good alternative is to detect recoiling protons from a heavier projectile.

GD-OES might also be a possibility.

Depending on your sample quality you could use Neutron Reflectometry.