Pd-Cu/羟磷灰石的制备及常温常湿CO催化氧化性能

通过溶胶-凝胶法(SG)和水热法(HT)合成了羟磷灰石载体(HAP-SG, HAP-HT), 以浸渍法制备负载型Pd-Cu/HAP催化剂(PC-SG, PC-HT), 并考察其常温常湿条件下CO催化氧化反应性能. 采用电感耦合等离子体发射光谱(ICP-OES)、 N₂物理吸附-脱附、 X射线衍射(XRD)、 傅里叶变换红外光谱(FTIR)、 H₂程序升温还原(H₂-TPR)、 CO₂程序升温脱附(CO₂-TPD)、 X射线光电子能谱(XPS)和CO原位漫反射傅里叶变换红外光谱(in-situ DRIFTS)等手段对Pd-Cu/HAP催化剂进行了表征. 结果表明, 相比于PC-SG, PC-HT具有较大比表面积和孔容, 含有较多的Cu₂Cl(OH)₃物种且与Pd物种和载体直接产生了较强的相互作用; 而且PC-HT表面含有较强CO活化能力的Pd⁺物种和更多具有较强氧化还原性质的Cu⁺物种, 以及较少数量和较低强度的碱性位点, 因而表现出更加优异的常温常湿条件下CO催化氧化性能.

Preparation and Characterization of Pd-Cu/hydroxyapatite Catalyst and Its Catalytic Performance for Room-temperature CO Oxidation in Humid Circumstances†

Hydroxyapatite supports(HAP-SG, HAP-HT) were prepared by sol-gel and hydrothermal methods, respectively. Pd-Cu/HAP catalysts(PC-SG, PC-HT) were synthesized by an impregnation method, and the catalytic activities toward CO oxidation at room temperature and in humid circumstances were investigated. The Pd-Cu/HAP catalysts were characterized by inductively coupled plasma optical emission spectrometry(ICP-OES), N₂-physisorption, X-ray diffraction(XRD), Fourier transform infrared(FTIR), H₂ temperature programmed reduction(H₂-TPR), CO₂ temperature programmed desorption(CO₂-TPD), X-ray photoelectron spectroscopy(XPS)and CO in-situ diffuse reflection using Fourier transform spectroscopy(DRIFTS). The results show that compared with PC-SG, PC-HT possesses the larger specific surface area and pore volume, contains more Cu₂Cl(OH)₃ species with stronger interactions with Pd species and support; more importantly, Pd⁺ species with stronger CO activation ability and more Cu⁺ species with stronger redox property, as well as fewer and weaker basic sites present in PC-HT, thus PC-HT exhibits more excellent CO catalytic oxidation performance for room-temperature CO oxidation in humid circumstances.