A graded catalytic–protective layer for an efficient and stable water-splitting photocathode

The present disclosure relates to a composition that includes, in order: a first layer that includes MAw; a second layer that includes MOyAz; and a third layer that includes MOx, where M includes a transition metal, A includes at least one of sulfur, selenium, and/or tellurium, w is between greater than zero and less than or equal to five, x is between greater than zero and less than or equal to five, y is between greater than zero and less than or equal to five, and z is between greater than zero and less than or equal to five. In some embodiments of the present disclosure, the transition metal may include at least one of molybdenum and/or tungsten. In some embodiments of the present disclosure, A may be sulfur.