Nanoparticulate gold catalysts supported on niobium oxides （Nb2O5） were prepared by different deposition methods. The deposition precipitation （DP） method, DP method with urea, deposition reduction （DR） method a...Nanoparticulate gold catalysts supported on niobium oxides （Nb2O5） were prepared by different deposition methods. The deposition precipitation （DP） method, DP method with urea, deposition reduction （DR） method and one‐pot method were used to prepare a 1 wt%Au/Nb2O5 catalyst. Lay‐ered‐type Nb2O5 synthesized by a hydrothermal method （Nb2O5（HT）） was the most suitable as a support among various types of Nb2O5 including commercially available Nb2O5 samples. It appeared that the large BET surface area of Nb2O5（HT） enabled the dispersion of gold as nanoparticles （NPs）. Gold NPs with a mean diameter of about 5 nm were deposited by both the DP method and DR method on Nb2O5（HT） under an optimized condition. The temperature for 50%CO conversion for Au/Nb2O5（HT） prepared by the DR method was 73 ＆#176;C. Without deposition of gold, Nb2O5（HT） showed no catalytic activity for CO oxidation even at 250 ＆#176;C. Therefore, the enhancement of the activity by deposition of gold was remarkable. This simple Au/Nb2O5 catalyst will expand the types of gold catalysts to acidic supports, giving rise to new applications.展开更多
文摘Nanoparticulate gold catalysts supported on niobium oxides （Nb2O5） were prepared by different deposition methods. The deposition precipitation （DP） method, DP method with urea, deposition reduction （DR） method and one‐pot method were used to prepare a 1 wt%Au/Nb2O5 catalyst. Lay‐ered‐type Nb2O5 synthesized by a hydrothermal method （Nb2O5（HT）） was the most suitable as a support among various types of Nb2O5 including commercially available Nb2O5 samples. It appeared that the large BET surface area of Nb2O5（HT） enabled the dispersion of gold as nanoparticles （NPs）. Gold NPs with a mean diameter of about 5 nm were deposited by both the DP method and DR method on Nb2O5（HT） under an optimized condition. The temperature for 50%CO conversion for Au/Nb2O5（HT） prepared by the DR method was 73 ＆#176;C. Without deposition of gold, Nb2O5（HT） showed no catalytic activity for CO oxidation even at 250 ＆#176;C. Therefore, the enhancement of the activity by deposition of gold was remarkable. This simple Au/Nb2O5 catalyst will expand the types of gold catalysts to acidic supports, giving rise to new applications.
