Band gap tuning of Na1-xLaxTa1-xCrxO3 for H2 generation from water under visible light irradiation

Semiconductors of Na1-xLaxTa1-xCrxO3 (x=0- 1.00) were prepared with conventional solid state reactions method. The crystal structure changed from monoclinic (x <= 0.60) to orthorhombic (x > 0.70) with the modulation of chemical composition. H-2 generation under visible light irradiation (lambda > 420 nm) was successfully obtained with the tuning of band structures of Na1-xLaxTa1-xCrxO3. The highest performance for H-2 generation (4.5 mu mol/h) was observed at x= 0.4 with apparent quantum yield of 0.5%. The visible light harvesting as well as the photocatalysis was further discussed based on the electronic structures thereof. (C) 2009 American Institute of Physics. [doi:10.1063/1.3243282]