Unprecedented iron-based photoelectrocatalysts@graphene foam composites as electrolyzing nanomaterials for water splitting in a neutral environment

Using nonprecious metal catalysts to efficiently produce large capacities of H2 and O2 from water splitting through the photoelectrolysis path is a crucial objective. The FeS2/alpha-Fe2O3 composite is first synthesized using thiourea under hydrothermal conditions and is subsequently combined with different weight ratios of graphene foam (GF; 6-20 %). The catalyst FeS2/alpha-Fe2O3@11 %GF demonstrates the highest photoelectrochemical water splitting activity at an excessive potential of 0.17 V, accomplishing a current density of 10 mA cm-2 and a Cdl of 2.14 mF cm-2 for HER, exceeding Pt/C results (0.53 V, 2.0 mF cm-2). OER, on the other hand, exhibits an overpotential of 0.18 V at 10 mA cm-2 and a low Tafel slope value of 77.9 mV dec- 1, causing a very considerable rise in the reaction kinetics with a noticeably stable behavior. Total water splitting was achieved using the FeS2/ alpha-Fe2O3@11 %GF || FeS2/alpha-Fe2O3@11 %GF electrolyzer with a small cell voltage of 1.63 V to produce 10 mA cm-2. Due to the significant interfacial effects produced by the well-integrated GF, boosted pore volume and surface area, abundance of accessible sites of activity, and growing Fe2+/Fe3+ ratio, which significantly improved electron transfer and electrolyte transport, the three-component system improved its ability to achieve efficient water splitting.