Promotion of efficient chlorine evolution reaction by d-p hybrid orbitals in hollow porous CoNiSe2/NiSe2 nanosheet arrays
The global demand for chlorine gas continues to rise, driven by its indispensable role in chemical synthesis, disinfection, and wastewater treatment. Electrocatalytic chlorine evolution from seawater presents a promising alternative to the energy-intensive chlor-alkali process, yet it is hampered by the competing oxygen evolution reaction and the sluggish kinetics of chlorine evolution on conventional catalysts. Here, we report a novel hollow porous CoNiSe2/NiSe2 heterostructure nanosheet array synthesized via ion exchange and calcination, which exhibits exceptional catalytic activity and selectivity for the chlorine evolution reaction in acidic seawater-like electrolytes. The unique hollow porous morphology provides a high specific surface area, facilitating mass transport and exposing abundant active sites. Crucially, the heterointerface between CoNiSe2 and NiSe2 promotes d-p orbital hybridization between Co/Ni 3d and Se 4p states, which lowers the reaction energy barrier for chlorine evolution. The catalyst achieves a low overpotential of 108 mV to reach a current density of 100 mA cm−2 in 4.0 M NaCl acidic medium, with excellent stability and Cl2 selectivity. This work demonstrates the potential of non-noble metal selenides as efficient and durable catalysts for chlorine production, offering a pathway toward more sustainable chlor-alkali technology.