MnO doped SnO2 nanocatalysts: Activation of wide band gap semiconducting nanomaterials towards visible light induced photoelectrocatalytic water oxidation

Semiconducting nanomaterials are very important by means of their stability and wide band gap tunability. Visible light induced photoelectrocatalytic water oxidation based on these material are challenging as they have large band gap energies. Herein, we report that MnO doping can activate wide band gap semiconductors like SnO2 towards visible light induced water oxidation. Rutile SnO2 nanoparticles (band gap 3.6 eV), usually absorbing at UV region, was capable of harvesting visible light when doped with MnO thereby minimizing the energy requirement for photoelctrocatalytic water splitting. The system was characterized using UV–Vis, TEM and XPS. Photoelectrocatalytic activity was examined by LSV and CPE. The highly stable catalyst showed very good photoelectrocatalytic activity for the oxidation of water under alkaline condition with low overpotential of ∼370 mV at 1.0 mA cm−2.