纳米金复合催化剂制备及其低温选择催化环己烷氧化性能

采用光催化直接还原法将Au(0)负载在TiO2修饰的中孔分子筛MCM-41的孔道内外，采用XRD, N2吸附-脱附，FT-IR, TEM和EDS等手段对所制催化剂进行了表征，并考察了其在温和条件下对环己烷选择性氧化反应的催化性能. 结果表明，所制纳米金催化剂的分子筛载体仍具有较高的结晶度，金颗粒粒径在10 nm左右. 在环己烷氧化反应中，纳米金与TiO2光催化共同作用，使复合催化剂具有低温高催化活性. 在温度100℃、压力1.0 MPa及250 W紫外灯光照8 h的条件下，环己烷转化率高达3.9%，目的产物的总选择性为90.2%.

Preparation of Nano-sized Gold-doped TiO_2 Catalyst and Its Performance for Selective Oxidation of Cyclohexane at Low Temperature

Nano-sized Au clusters were deposited into the inner or outer surface of titania-modified MCM-41 by photodeposition method. The prepared samples were characterized by XRD, N_2 adsorption isotherm, TEM and EDS. Their catalytic performance for oxidation of cyclohexane was investigated under mild conditions. The results showed that all the MCM-41support of prepared catalyst samples had high crystallinity and the size of gold particles was about 10 nm. The complex nano-sized gold catalysts exhibited high catalytic activity at low-temperature,due to the synergistic effect of nano-sized gold and photocatalysis for oxidation of cyclohexane. The catalytic performance of the prepared samples for the selective oxidation of cyclohexane under mild conditions using molecular oxygen in a solvent-free system was investigated. The conversion rate of cyclohexane was 3.9% and the total selectivity of purposed products 90.2% under the conditions of 100℃, 1.0 MPa and illumination by 250 W UV-lamp for 8 h.