CuCoO2 nanocrystals derived from an isopropanol-modified Cu-BTC using alkaline water oxidation

Abstract

In this study, CuCoO₂ (CCO) nanocrystals were derived from the Cu-BTC/Cu-BTC-IPA precursors using the solvothermal method at 140 °C, and the electrocatalytic oxygen evolution reaction (OER) application of CCO catalysts was investigated. First, the optimized Cu-BTC-IPA precursor was prepared through a hydrothermal reaction at 120 °C with 9 mL isopropyl alcohol (IPA) addition. IPA species can affect the morphology and composition of CCO nanocrystals by tailoring the structure of bare Cu-BTC, resulting in Cu-BTC-IPA-derived CCO2 nanocrystals that have a smaller grain size of 110 nm and a larger specific surface area of 9.78 m² g⁻¹, which is compared to that of Cu-BTC-derived CCO1 nanocrystals. Second, the Ni@CCO2 electrode required an overpotential of 467 mV to reach 10 mA cm⁻², which is much lower than that of the Ni@CCO1 electrode (i.e., 493 mV). The Ni@CCO2 electrode also exhibits a small overpotential degradation of only 20 mV after an 18 hour OER stability test. The measurement results confirmed that the CCO2 catalyst has excellent stability in structure and composition during long-term OER electrolysis. This study reveals the preparation method of a CCO electrocatalyst by tailoring the organic ligands of MOF precursors, supplying a new approach for the preparation of delafossite oxide CCO and the enhancement of their OER performances.