Deep self-reconstruction of CoF2 to hierarchically defective Co(OH)2 nanosheets for electrocatalytic reduction of nitrate to ammonia

Hierarchical Co(OH) 2 nanosheets with abundant defects in situ reconstructed from the “pre-catalyst” of a CoF 2 array. They are highly selective and active electrocatalysts for nitrate reduction into ammonia with a large yield of 0.62 mmol h −1 cm −2 .