Diatomic catalytic sites on MOF-derived architecture towards effective H2 production

It is a recognized challenge that the elaborate design of metal-organic framework (MOF) derived architecture with tunable electronic structure to achieve efficient catalytic capacity, especially involving in multiatomic catalytic sites. Herein, employing electrochemical reconstruction of Rh-doped Co-BTC MOF, a new catalyst with a unique dual-modified architecture of surface decoration of Rh quantum dots (QDs) and lattice doping of Rh atoms, Rh QD /Rh-CoC 2 O 4 , is fabricated. The key Co-H* and Rh-H* intermediates are detected by in situ shell-isolated nanoparticle enhanced Raman spectroscopy (SHINERS), confirming that the Rh/Co diatomic catalytic sites are created in the Rh QD /Rh-CoC 2 O 4 catalyst. Density functional theory (DFT) calculations further uncover that this unique dual-modified architecture synergistically regulates electronic structure such as electron transfer capacity, d-band center and interfacial electron distribution, which enables the Rh and Co atoms in the Rh-doped lattice matrix of CoC 2 O 4 at the interface with Rh QDs to be effectively triggered, thereby reducing the energy barrier of the hydrogen generation reaction (HER). As a result, the overpotential of the optimal Rh QD /Rh-CoC 2 O 4 -3 catalyst is only 16.5 mV at the current density of 10 mA cm −2 in acidic medium, well below that of the Pt/C benchmark (31.0 mV) and the recently reported Rh-based catalysts. Moreover, it can remain stable operation for more than 120 h without attenuation. This contribution emphasizes the significance of MOF reconstruction in electrocatalytic reactions and sheds a new light on the synergistic regulating effect of MOF-derived catalysts with complex architecture.