Despite the availability of abundant, inexpensive non-noble metal-based anode catalysts for alkaline water electrolysis, the cathodic hydrogen evolution reaction (HER) continues to be a challenge, even in the case of state-of-the-art Pt catalysts. In such proton-deficient environments, a metal hydroxide-/oxide-based co-catalyst that can help polarize the H-O bond in water has been found to promote proton abstraction and subsequent reduction into H