Thermally activated carbon–nitrogen vacancies in double-shelled NiFe Prussian blue analogue nanocages for enhanced electrocatalytic oxygen evolution

Double-shelled NiFe PBAs nanocages with abundant CN vacancies have been fabricated through an ion-exchange reaction based on a nanoscale Kirkendall effect followed by mild thermal activation, which have an impressive OER activity with low overpotential and long-term stability.