Raman and electrochemical probes of the dissolution kinetics of tungsten in hydrogen peroxide

The interaction of tungsten with hydrogen peroxide was studied by Raman spectroscopy and electrochemical measurements. We found that W catalyzes the decomposition of peroxide into its ion, while the native oxide of W becomes increasingly hydrated and soluble. The decay of the peroxide concentration upon immersion of W is consistent with a model of 1-D diffusion to the W surface followed by a surface reaction with a heterogeneous rate constant of 3 x 10(-5) cm/s. This model can also be used to explain the decrease of the H2O2 solution pH and the increase in open circuit potential of W that occurs while W is immersed in H2O2.