Inspired by high-entropy materials, it is a worthwhile direction to develop multi-metal integrated catalysts to study their synergistic catalytic effects in catalysis field. However, achieving this in porous crystalline materials like covelent organic frameworks (COFs) for backend catalysis reactions remains scarce and challenging to date. Herein, a series of multi-metal-variate COFs (i.e., Quint-MMV-COF, Tetra-MMV-COF and Tri-n-MMV-COF (n = 1, 2 and 3)) have been prepared that can be applied in indirect electrocatalysis. These MMV-COFs with advantages of multi-metal sites, porous structures and appropriate work function can serve as solid-phase redox mediators for the catalytic production of liquid-phase S-S bond products and gas-phase H₂ product. Interestingly, the optimal Quint-MMV-COF presents excellent electrocatalytic efficiency for S-S bond products (yields up to 99%) and H₂ (~1.62 mmol·g^–1·h^–1) and can be readily recycled for 6 cycles. At the same time, 1.52 g product with a yield of ~92% can be obtained in the amplification reaction, showing much potential in industrial production. Validated by theoretical calculations, the synergistic effect of multi-metal sites can result in appropriate work function to boost the electron transfer and intermediate adsorption/conversion to achieve excellent overall S-S coupling efficiency.

The lower electricity consumption (EC) and higher value-added products are much desired yet still challenging for the development of CO₂ coupling electrocatalytic systems. Herein, we give insight into the inherent nature of the retrenchment of EC by exploring the photo-assisted co-electrolysis of methanol and CO₂ system using a kind of hydroxyl-rich covalent organic frameworks (Dha-COF-Co) with well-tuned pore structure and morphology. Specifically, the hydroxyl induced hydrogen bond interaction in Dha-COF-Co enables to simultaneously regulate the pore microenvironment and nanoribbon morphology of COFs for performance boosting. Notably, the obtained Dha-COF-Co nanoribbon exhibits an overall EC retrenchment of ~41.2% (highest in porous crystalline materials to date) when replacing the anodic OER with MOR in the photo-electrocatalytic MOR-CO₂RR coupling system, as well as superior FE_HCOOH (anode, ~100%) and FE_CO (cathode, >95%) at 1.8 V. Combined theoretical calculations with various characterizations, the vital role of hydroxyl group in both microenvironment and morphology tuning that can facilitate the CO₂RR and MOR kinetics to retrench the EC has been intensively discussed.