Covalent Linking of the Porphyrin Light Harvester to the Multiwalled-Carbon-Nanotube-Based Polypyridineruthenium(II) Complex for Boosting the Electrocatalytic Oxygen Evolution Reaction

The oxygen evolution reaction (OER) is a key step in artificial photosynthesis, and protons and electrons generated in the reaction are vital for subsequent cathodic reactions. In this paper, a light-assisted photoelectrocatalytic system constructed by the OER catalyst (tpyRubpy) and light-harvesting moiety (porphyrin) was further covalently grafted onto the multiwalled carbon nanotubes (MWCNTs). The formed nanocatalyst preserves both the high-efficiency catalytic OER performance of tpyRubpy and the light-harvesting performance of porphyrin, and the graft of MWCNT results in a decrease in the charge-transfer resistance of the composite electrode and achieved an excellent light-assisted electrocatalytic OER property with a lower onset potential of 1.57 V and a lower overpotential of 440 mV at a current density of 10 mA cm–2. This photoelectrocatalytic system successfully opens a new avenue for the rational design and fabrication of artificial photosynthesis systems through a covalent assembly strategy that mimics the key functions of photosystem II.