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

Abstract

• Three kinds of Dye waste are reused in the preparation of N-doped carbon supported TiO 2 catalysts. • The ultrasmall size of TiO 2 are in-situ synthesized and loaded. • The abundant TiO 2 -N-C interfaces with different types of N-doping are achieved. • The TiO 2 @N-doped carbon catalyst prepared by methyl orange shows excellent OER activity and stability. • DFT calculation reveals the graphitic-N accelerated reaction mechanism. 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 TiO 2 supported on N-doped carbon (TiO 2 @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. TiO 2 are sputtered and loaded onto carbon simultaneously during the one-step synthesis process. TiO 2 @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 TiO 2 @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 TiO 2 -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.