Mechanochemical one-pot synthesis of heterostructured pentlandite-carbon composites for the hydrogen evolution reaction.

We have utilized carbon sources as milling additives to enable a direct mechanochemical one-pot synthesis of Fe 3 Co 3 Ni 3 S 8 /carbon (Pn/C) materials using elemental reaction mixtures. The obtained Pn/C materials are thoroughly characterized and their carbon content could be adjusted up to 50 wt%. In addition to carbon black (CB) as an additive, Pn/C materials were produced using graphite, reduced graphene oxide (rGO), and carbon nanotubes (CNTs), which allows the overall physicochemical properties of materials for energy storage applications to be adjusted. By employing the Pn/C materials as electrocatalysts for the HER in a zero-gap proton exchange membrane (PEM) electrolyzer, we were able to reach a current density of 1 A cm -2 at a cell potential as low as 2.12 V using Pn, which was synthesized with 25 wt% CB. Furthermore, electrolysis at an applied current density of 1 A cm -2 for 100 h displays a stable performance, thus providing a sustainable synthesis procedure for potential future energy storage applications. Herein, we show that catalyst supports play an important role in the overall performance.