Cobalt/cobalt phosphide/nitrogen-doped carbon derived from zeolitic imidazolate framework-11@zeolitic imidazolate framework-12 core-shell structure as efficient electrocatalyst for oxygen evolution reaction

Electrochemical water splitting is considered as a promising and efficient way to produce hydrogen and oxygen, which are regarded as sustainable energy. Zeolitic imidazolate frameworks (ZIFs) have been widely utilized as sacrificial templates for synthesizing efficient electrochemical active materials with porous structure and tunable pore properties. In this study, cobalt/cobalt phosphide on N-doped carbon matrix (CPZ11@12-150) derived from the novel core-shell structure of ZIF-11@ZIF-12 is reported as a highly efficient electrocatalyst for oxygen evolution reaction (OER). With the enhanced electrical conductivity from N-doped carbon and excellent electrocatalytic activity from cobalt phosphide, the CPZ11@12-150 possesses a low overpotential (274 mV) at 10 mA cm-2 and a small Tafel slope of 76.2 mV & sdot;dec- 1 in 1 M KOH. The CPZ11@12-150 also shows superior longterm stability for at least 100 h, owing to good attachment of CoP on N-doped carbon matrix and its mesoporous structure for effective releases of O2 bubbles.