Effect of H2/CO2 mixture gas treatment temperature on the activity of LaNiO3 catalyst for hydrogen production from formaldehyde aqueous solution under visible light

H-2/CO2 mixture gas treatment at moderate temperature is found to be effective in improving the activity of LaNiO3 catalyst for hydrogen production from formaldehyde aqueous solution under visible light. The LaNiO3, as a precursor, was treated at various temperatures (573-973 K) for 4 h under continuous flow mixture gas with a molar ratio of H-2/CO2 = 4:1. Among all the resultant photocatalyst, the LaNiO3 treated at 773 K (Ni/LaNiO3-delta-La2O2CO3), exhibited highest photocatalytic activity when exposed to visible-light irradiation and was further characterized by XRD, SEM, TEM, UV-diffuse reflectance spectroscopy. The results indicated that Ni/LaNiO3-delta-La2O2CO3 photocatalyst had narrow bandgap and can efficiently transfer photogenerated electrons on the surface and thus reduce H+ to hydrogen. (C) 2009 Elsevier B.V. All rights reserved.