Efficient and Raw Material Free HER Catalysts Based on Doped ZIF Structures in Strong Acidic and Basic Conditions and Improvement with Co$_2$Mo$_3$O$_8$ Nanostructures

International audienceOne of the most challenging issues in the 21$^{st}$ century is the global energy crisis and the connected climate change. A way to target both problems is to use alternative energy source to fossil fuel like hydrogen as energy carrier. A green and carbon neutral way of producing hydrogen is water splitting with renewable energies like solar. However, generating hydrogen through electrochemical water splitting is unattractive, due to the high process costs compared with steam reforming. To lower the cost of the electrochemical water splitting it is crucial to work on alternatives for the rare and expensive platinum hydrogen evolution reaction (HER) catalyst. As part of the eSCALED project, which aims to develop an artificial leaf, this work is focused on the electrochemical hydrogen evolution with inexpensive and efficient earth abundant metals as catalysts. In this work, we present nanoparticles catalysts based on a highly porous zeolitic imidazolate framework (ZIF). The ZIF-8 structures were doped with earth abundant metals (Mn, Mg, Co, Ni and Fe). Some ZIFs were further improved with Co$_2$Mo$_3$O$_8$ nanostructures to combine the high porosity and electrical conductivity of carbonized ZIFs with the outstanding catalytic activity of Co$_2$Mo$_3$O$_8$. Both, ZIFs and Co$_2$Mo$_3$O$_8$ nanoparticles were tested in pH 0 as well as in pH 14 at room temperature in different configurations