Yan Wenfu, Chen Bei, Mahurin S M, Schwartz V, Mullins D R, Lupini Andrew R, Pennycook S J, Dai Sheng, Overbury S H
Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6201, USA.
J Phys Chem B. 2005 Jun 2;109(21):10676-85. doi: 10.1021/jp044091o.
Nanosized anatase (< or = 10 nm), rutile (< or = 10 nm), and brookite (approximately 70 nm) titania particles have been successfully synthesized via sonication and hydrothermal methods. Gold was deposited with high dispersion onto the surfaces of anatase, rutile, brookite, and commercial titania (P25) supports through a deposition-precipitation (D-P) process. All catalysts were exposed to an identical sequence of treatment and measurements of catalytic CO oxidation activity. The as-synthesized catalysts have high activity with concomitant Au reduction upon exposure to the reactant stream. Mild reduction at 423 K produces comparably high activity catalysts for every support. Deactivation of the four catalysts was observed following a sequence of treatments at temperatures up to 573 K. The brookite-supported gold catalyst sustains the highest catalytic activity after all treatments. XRD and TEM results indicate that the gold particles supported on brookite are smaller than those on the other supports following the reaction and pretreatment sequences.
通过超声处理和水热法已成功合成了纳米级锐钛矿（≤10纳米）、金红石（≤10纳米）和板钛矿（约70纳米）二氧化钛颗粒。通过沉积沉淀（D-P）工艺将金以高分散度沉积在锐钛矿、金红石、板钛矿和商用二氧化钛（P25）载体的表面。所有催化剂都经历了相同的处理顺序和催化CO氧化活性的测量。所合成的催化剂在暴露于反应物流时具有高活性并伴随金的还原。在423K下进行温和还原可为每种载体产生具有相当高活性的催化剂。在高达573K的温度下进行一系列处理后，观察到四种催化剂的失活。在所有处理之后，板钛矿负载的金催化剂保持最高的催化活性。XRD和TEM结果表明，按照反应和预处理顺序，负载在板钛矿上的金颗粒比负载在其他载体上的金颗粒小。
