Distinctive 3D heterostructures of partial sulfidation with FeCo LDH: A potent electrocatalyst for synergistic alkaline overall water splitting

The reasonable surface engineering allows effective modification of the adsorption energy of reactive hydrogen molecules, resulting in the improvement of the effectiveness of water separation. Herein, we fabricated MoS2-FeCoS2-FeCo LDH/NF (defined as: MS-FCS-FCL/NF) sea urchin-like nanospike sphere catalysts with heterogeneous interfaces by a simple two-step hydrothermal method and simultaneous sulfurisation of FeCo LDH for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), which optimised the electronic structure and exposed more active sites, thus revealing excellent electrocatalytic performance. As predicted, the synthesized 3D "sea urchin-like" structure MS-FCS-FCL/NF has excellent HER (η10 = 176 mV) and OER (η10 = 149 mV) properties. Remarkably, when used as a bifunctional catalyst to perform overall water decomposition, it requires just a low cell voltage (1.53 V for 10 mA cm−2) and has outstanding stability (48 h). Density functional theory (DFT) calculations have proven that tuning electron dissipation and aggregation at heterogeneous interfaces can optimize the electron transfer rate in the active sites and D-band centers near the Fermi level and enhance the inherent catalytic activity. This work provides both an elegant method for building hierarchical heterostructures and a multiscale strategy for water separation electrocatalyst.