Facile synthesis of ultrathin interconnected carbon nanosheets as a robust support for small and uniformly-dispersed iron phosphide for the hydrogen evolution reaction

Supports play crucial role in determining the catalytic activity, selectivity and overall performance of the supported catalytic nanoassemblies. Herein, ultrathin interconnected carbon nanosheets (CN) are prepared and used as a robust support for dispersion of iron phosphide (FeP) nanoparticles, and the resulting catalytic system is evaluated as low-cost electrocatalyst for hydrogen evolution reaction (HER). Carbon is derived from carbonization of sodium citrate in one-step, which is interconnected and in the form of ultrathin nanosheets (thickness <5 nm) with high surface area. Such morphological features of carbon steered the growth of small FeP nanocrystals with better dispersion qualities. As a result, the electrode comprising FeP-modified ultrathin interconnected carbon nanosheets (FeP/CN) exhibits excellent HER performance both in acidic and basic electrolytes; requires small onset and overpotential, and possesses high turnover frequency (TOF), in addition to excellent operational stability. The performance of FeP/CN electrode is compared with that of commercial carbon-supported platinum (Pt/C) and supportless FeP nanoparticles. Superior performance of the electrode comprising FeP/CN is correlated to specific surface area, electrochemically active surface area, interfacial charge transfer resistance and TOF.