Self-reconstructed ZIF-L/Co(OH)2 heterointerface modulates electronic structure of Ru and boosts electrocatalytic hydrogen evolution

Abstract

Understanding the self-reconstruction behavior and activity modulation mechanism of MOFs in alkaline electrocatalysis is important for developing efficient Ru-based catalysts. As Co-based MOFs, leaf-shaped zeolitic imidazolate framework (ZIF-L) crystals can be partially self-reconstructed to Co(OH)2 by in situ alkaline electrochemical methods. In this regard, two models of ZIF@Ru/NF and Co(OH)2-ZIF@Ru/NF were fabricated, and calculated by DFT. The results showed that the Co(OH)2-ZIF heterointerface generated by self-reconstruction effectively modulated the chemical and electronic environment of Ru, leading to enhanced HER performance. Therefore, Co(OH)2-ZIF@Ru/NF was in situ grown on nickel foam (NF), using ZIF@Ru/NF as a precursor. After LSV activation, the leaf-shaped ZIF-L transformed into finely fragmented nanosheets of Co(OH)2. As anticipated, the Co(OH)2-ZIF@Ru/NF catalyst demonstrated superior electrocatalytic performance compared to numerous reported counterparts, exhibiting an overpotential of 22 mV at a current density of 10 mA cm−2 and a Tafel slope of 16.9 mV dec−1. This study presents a viable method for the preparation of HER electrocatalysts using electrochemical in situ self-reconstruction.