Hollow CoNiSe₄/Fe₃Se₄ Trimetallic Selenides Derived from Zeolitic Imidazolate Framework-67 as Efficient Electrocatalysts for Oxygen Evolution Reaction

The development of efficient and stable electrocatalysts for the oxygen evolution reaction (OER) is a key way to improve the efficiency of electrochemical overall water splitting and thus achieve sustainable energy in the future. Here, a strategy of step-by-step introduction of different metal elements to prepare the delicate hollow nanoboxes of trimetallic selenide (CoNiSe₄/Fe₃Se₄) has been presented for boosting OER. By means of ion exchange, chemical etching, and low-temperature gas-phase selenization, the solid zeolitic imidazolate framework-67 (ZIF-67) has been transformed into the hollow CoNiSe₄/Fe₃Se₄ in which the nickel element is mainly positioned on the surface of the nanoboxes. These structural and compositional advantages render CoNiSe₄/Fe₃Se₄ to exhibit excellent catalytic activity (266 mV@10 mA cm^-2 and 300 mV@50 mA cm^-2) and good long-term stability (80 h@10 mA cm ^-2). This study provides an ingenious synthetic method for the preparation of ZIF-67-based hollow trimetallic selenide OER electrocatalysts.