In situ self-assembled macroporous interconnected nanosheet arrays of Ni-1,3,5-benzenetricarboxylate metal - organic framework on Ti mesh as high-performance oxygen evolution electrodes.

Highly efficient metal-organic framework (MOF)-based oxygen evolution reaction (OER) catalysts are desirable for water splitting, but their development remains challenging due to poor accessibility of coordinatively unsaturated metal (cum) sites and low intrinsic activity. A large-area three-dimensional (3-D) macroporous interconnected nanosheet array of Ni-1,3,5-benzenetricarboxylate has been in situ self-assembled on Ti mesh (TM) by using ethanol as the solvent and high-affinity oxide layer on TM to promote in situ nucleation. The obtained nanoarchitecture exhibits much superior catalytic activity compared to most reported catalysts including MOF-based catalysts, other precious-metal-free ones, and Ir/Ru-based ones. Additionally, this electrode undergoes no current decay after 300 cyclic voltammetry (CV) cycles and can maintain at 250 mA cm for over 266 h. The excellent catalytic performance is mainly due to the 3-D macroporous and interconnected nanosheet array structure improving cum site exposure and charge transport and in situ activated cum cations enhancing OH adsorption. This work not only develops a facile and economical approach to synthesize 3-D macroporous interconnected MOF nanosheet arrays to simultaneously increase the number, exposure, and intrinsic activity of active sites and facilitate charge transport for high-performance eletrocatalysis, but provides scientific insights into the mechanisms for self-assembly of this unique nanoarchitecture and for the high OER performance.