Construction of graphitic-N-rich TiO2-N-C interfaces via dye dissociation and reassembly for efficient oxygen evolution reaction

Environmental pollution and the energy crisis are two major threats to human beings. The textile printing and dyeing industry use synthetic dyes to color its products producing lots of wastewater. In this work, ultrasmall size of TiO2 supported on N-doped carbon (TiO2@NC) have been prepared via electron-induced dye dissociation and reassembly method. The dye precursors of methyl orange (MO), methylene blue (MB), and rhodamine B (RB) provide N and C sources. TiO2 are sputtered and loaded onto carbon simultaneously during the one-step synthesis process. TiO2@NC-MO with the highest proportion of graphitic-N exhibits the best OER performance with a low overpotential (325 mV at 10 mA cm−2) and excellent durability (over 50,000 s at 10 mA cm−2) in alkaline solution. A two-electrode electrolyzer is assembled by using TiO2@NC-MO as anode and cathode in 1.0 M KOH media for the overall water splitting, which delivers an initial cell voltage of only 1.71 V at 10 mA cm−2, as well as long-term stability up to 50,000 s. Density functional theory calculations verification that the TiO2-N-C interface with high radio of graphitic-N leads to the optimal catalytic activity. This study sheds light on the recycling and reuse of dye wastewater for the fabrication of highly efficient electrocatalysts with controllable N-doping structures and metal oxide size via a novel eco-friendly approach.