Adding some additional references on the photoreduction of CO2 or CO with hydrogen to form methane, over metal oxide dust catalysts:<br /><br />Research on Chemical Intermediates<br />Volume 26, No. 1, p. 93<br />"Photoreduction of carbon dioxide by hydrogen and methane<br />T. Tanaka, Y. Kohno and S. Yoshida"<br /><br />"Photochemical reduction of CO2 using Cu-loaded silicate rock powder suspended in water<br /><br />Kiyohisa Ohta, Youko Ueda, Satoshi Nakaguchi, and Takayuki Mizuno <br />Can. J. Chem./Rev. Can. Chim. 76(2): 228-233 (1998) "<br /><br />"I-H. Tseng, W.-C. Chang, J. C. S. Wu, "Photoreduction of CO2 using Sol-Gel-Derived Titania and Titania-Supported Copper Catalysts," Applied Catalysis B: Environmental, vol. 37(1), 37-48, 2002. "<br /><br />"E. Fujita, Photochemical Carbon Dioxide Reduction with Metal<br />Complexes, Coordination Chemistry Review, vol. 18.5186, 373-384, 1999; N. Sutin, C. Creutz.<br />and E. Fujita, Photo-Induced Generation qf Dihydrogen and Reduction of Carbon Dioxide Using<br />Transition Metal Complexes, Comments Inorg, Chem. vol. 19,67-92, 1997; T. Inui, M. Anpo.<br />K. Izui, S. Yanagida, and T. Yamaguchi (Eds.) Advances in Chemical Conversions for<br />Mitigating Carbon Dioxide, Studies in Surface Science and Catalysis, Vol. 114, Amsterdam,<br />Elsevier, 1998." <div class="Discussion_UserSignature"> <div class="Discussion_UserSignature" align="center"><em><font color="#0000ff">- - - - - - - - - - - - - - - - - - - - - -</font></em> </div><div class="Discussion_UserSignature" align="center"><font color="#0000ff"><em>I really, really, really miss the "first unread post" function.</em></font> </div> </div>