In situ generation of oxyanions-decorated cobalt(nickel) oxyhydroxide catalyst with high corrosion resistance for stable and efficient seawater oxidation

The development of efficient and robust anode materials for stable alkaline seawater electrolysis is severely limited by chlorine evolution reaction and chloride corrosion. Here, the sulfur-doped cobalt-nickel bimetallic phosphides (CoNiPS) are specifically designed as a pre-catalyst for navigating a surface reconstruction to fabricate the anions (PO43− and SO42−)-decorated Co(Ni)OOH catalyst (R-CoNiPS) with exceptional durability and high activity for stable alkaline seawater oxidation (ASO). Various experiment techniques together with theoretical simulations both demonstrate that the in situ-generated PO43− and SO42− anions on catalyst surface can improve the oxygen evolution reaction (OER) activity, regulating and stabilizing the catalytic active species Co(Ni)OOH, as well as make a critical role in inhibiting the adsorption of chloride ions and extending the service life of electrode. Therefore, this R-CoNiPS electrode exhibits superb OER activity toward ASO and stands out among the non-precious ASO electrocatalysts reported recently, requiring low overpotentials of 420 and 440 mV to attain large current densities of 500 and 1000 mA cm−2 in an alkaline natural seawater electrolyte, respectively. Particularly, the catalyst displays a negligible chloride corrosion at room temperature during ASO operation (>200 h) at 500 mA cm−2. This work opens up a new viewpoint for designing high-activity and durable electrocatalysts for seawater electrolysis.