Designing cactus-like Fe-P doped CoNi-S arrays as highly efficient electrocatalyst for overall water splitting

• Cactus-like structure of Fe, P- CoNi-S was designed and prepared. • The Fe, P-CoNi-S/NF presents good catalytic activity for HER and OER. • The dual doping of Fe and P simultaneously enhances the activity and durability. • The exceptional electrochemical performances of Fe, P-CoNi-S/NF are due to its dual regulation of electronic structure and morphology. Exploring high activity, stable and low-cost electrocatalysts are of great importance for high-efficient hydrogen production via water splitting. Herein, a cactus-like Fe, P co-doped CoNi-S array was constructed via facile hydrothermal reaction and subsequently sulfuration and phosphorization process. Benefiting from the strong synergistic effects of different components, high conductivity of bimetallic sulfide, 3D cactus-like architecture with rich channels for mass/charge transport, and Fe and P co-doping with electron structure regulation, the as-prepared Fe, P-NiCo 2 S 4 /NF presents superior electrocatalytic activity with low overpotentials of 139 and 290 mV to drive the current density of 10 and 40 mA cm -2 for HER and OER, respectively. Meanwhile, it also manifests the distinguished durability for over 60 h in alkaline media. Notably, when integrating in a two-electrode electrolytic cell with Fe, P-CoNi-S, a reduced operation voltage of 1.55 V is required to reach 10 mA cm -2 , which is superior to precious metal-based Pt/C/NF//RuO 2 /NF counterparts. Impressively, it can also be driven by sustainable solar and thermal energies motivated Stirling engine. This work offers a universal strategy for designing high-activity and durable electrocatalysts by dual doping heteroatoms and synergistic interface engineering.