Synergistic Effect of High-Performance N,S–TiO2/N,S–RGO Nanocomposites for Photoelectrochemical Water Oxidation

Nitrogen and sulfur codoped mesoporous anatase–brookite biphasic TiO2 anchored on surface of nitrogen and sulfur codoped reduced graphite oxide nanocomposites (N,S–TiO2/N,S–RGO) were easily prepared via a simple hydrothermal reaction process. XRD and Raman revealed anatase and brookite mixed phases. Also, the selected area electron diffraction (SAED) and the fast Fourier transform (FFT), from HRTEM measurements, indicated the presence of the anatase and brookite two phases. XPS showed the incorporation of N and S in both TiO2 matrix and carbon framework structure of RGO. The N,S–TiO2/N,S–RGO photoanodes exhibited an excellent photoelectrochemical (PEC) water oxidation performance. The highest photocurrent density reached 1.1 mA cm−2 for the N,S–TiO2/N,S–RGO(0.1) nanocomposite photoanode which is 6 times enhancement greater than bare TiO2 and 5 times enhancement than the N–TiO2/N–RGO(0.1) (the same GO ratio) at the same potential. These are considered significant promising results in comparison with our previous reported S–TiO2/S–RGO nanocomposite which revealed only 3 times enhancement in photocurrent density than bare TiO2.