Creating Dual Active Sites in Conductive Metal-Organic Frameworks for Efficient Water Splitting

The achievement of bifunctional metal-organic frameworks (MOFs) remains a huge challenge due to their lack of dual active sites. Herein, dual sites in the Co-catecholate (Co-CAT) are created through Ru, Ir, or Rh doping for overall water splitting. Among them, RuCo-CAT exhibits excellent bifunctional activities, outperforming benchmarked Pt/C for the hydrogen evolution reaction (HER) and RuO2 for the oxygen evolution reaction (OER). The theoretical calculations demonstrate that the doped Ru atoms with optimal absorption energy for the hydrogen intermediate and the Co centers with a reduced energy barrier for the rate-determining step are the active sites for HER and OER, respectively. Furthermore, the incorporation of Ru atoms can improve the electrical conductivity and capacity of water adsorption of Co-CAT greatly, synergistically improving the bifunctional activity. This strategy for engineering dual active sites offers novel insights into designing bifunctional MOFs for overall water splitting.