Electron redistribution via two-dimensional van der Waals heterojunctions boosts trifunctional electrocatalysis in sandwich-like structured Co-MOF/TiN/NC composite

Two-dimensional van der Waals heterojunctions (2D vdWHs) have received significant attention owing to their extraordinary properties such as the reduced energy barriers and efficient charge transfer. However, there is limited research about the construction of 2D vdWHs in electrocatalysts for improving multifunctional performance. Herein, we report a sandwich-like structured Co-MOF/TiN/NC-240 electrocatalyst with 2D vdWHs by one-step high-temperature solid-state and room-temperature ultrasonication methods, with 2D Co-MOF nanosheets uniformly assembled on the TiN/NC substrate. Ultraviolet Photoelectron Spectroscopy (UPS) reveal that the work function difference between Co-MOF and TiN/NC drives electron transfer from TiN/NC to Co-MOF, thereby modulating the metal oxidation state. The Co-MOF/TiN/NC-240 electrocatalyst exhibits boosted trifunctional electrocatalytic performances for ORR, OER, and HER , which can be attributed to the successful construction of 2D vdWHs, inducing effective electron redistribution via the heterogeneous interface and increasing the number of active sites. Moreover, the zinc-air battery (ZAB) and water-splitting device based on Co-MOF/TiN/NC-240 exhibit enhanced discharge capacity and superior efficiency, respectively. This study not only provides an effective design strategy to develop trifunctional electrocatalysts by constructing 2D vdWHs but also offers valuable insights into the enhanced electrocatalytic performance in the sustainable energy field.