Metal ion-assisted conversion of Co-ZIF-L to CoNi-layered double hydroxides with high electrochemical properties for supercapacitors

Morphology-engineered porous flower-like CoNi-LDO with oxygen vacancies for the production of aromatic amines through waste H2S

The efficient utilization of hydrogen resources in H2S has aroused great attention in both resource utilization and environmental protection. Using H2S as a hydrogen resource donor for the reduction of nitrobenzene to aniline could be an effective method to replace H2. Herein, we fabricated the porous flower-like CoNi-LDO catalyst through facile morphology control engineering, which utilizes DMF as an intercalating agent to influence the structure and properties. Endowed with abundant electron-rich oxygen vacancies and enhanced basic sites capacity, the as-designed CoNi-D catalyst exhibits considerable aniline selectivity (96 %) and high catalytic stability over seven cycles at 110 °C. The potential single H-induced dissociation pathway for the reduction of nitrobenzene to aniline by H2S was explored using in situ FT-IR analysis. The present study could provide a feasible strategy for designing catalysts for the high-value utilization of H2S.

Engineering intervention to disrupt the evolution of ZIF-67: Ultra-fast synthesis of arrayed Co(OH)2@ZIF-L in dozens of seconds for high-energy charge storage

Designing rational heterostructures of high-performance electroactive materials on conductive substrates with hierarchical structures is critical for advancing electrochemical energy storage technologies. In this study, a unique spatial structure is fabricated by vertically aligning two-dimensional (2D) structures of Co-ZIF-L on conductive nickel foam (NF) substrate through interruption of ZIF-67 formation. This is followed by an innovative electrochemical synthesis method that disrupts unstable surface coordination bonds in Co-ZIF-L, enabling the in-situ generation of Co(OH)2. The resulting Co(OH)2@ZIF-L/NF binder-free electrodes feature a hierarchical spatial structure and are synthesized in approximately 30 s. These electrodes showcase exceptional area capacity of 3.1 C cm-2 at 1 mA cm-2, attributed to their high specific surface area and layered architecture that promotes electrolyte penetration. Density Functional Theory (DFT) calculations reveal that the Co(OH)2@ZIF-L nanostructures have superior electrical conductivity compared to the individual components. Furthermore, a hybrid supercapacitor (HSC) based on Co(OH)2@ZIF-L/NF//AC exhibits an impressive energy density of 42 Wh kg-1 at a power density of 184.7 W kg-1. This research provides new insights into the efficient synthesis of high-performance electroactive materials with unique spatial structures and expands the potential applications of ZIF materials.