Superstructures of Organic–Polyoxometalate Co‐crystals as Precursors for Hydrogen Evolution Electrocatalysts

Molybdenum‐based carbides and nitrides have been considered as catalysts for the hydrogen evolution reaction (HER). One of the challenges in using Mo‐based HER electrocatalysts is establishing well‐defined precursors which can be transformed into Mo‐based carbides/nitrides with controllable structure and porosity. We report the synthesis of a series of superstructures consisting of organic–polyoxometalate co‐crystals (O‐POCs) as a new type of metal–organic precursor to synthesize Mo‐based carbides/nitrides in a controlled fashion and to use them for efficient catalytic hydrogen production. This protocol enables to create electrocatalysts composed of abundant nanocrystallites and heterojunctions with tunable micro‐ and nanostructure and mesoporosity. The best performing electrocatalyst shows high HER activity and stability with a low overpotential of 162 mV at 100 mA cm(−2) (in comparison to Pt/C with 263 mV), which makes it one of the best non‐noble metal HER catalysts in alkaline media and seawater.