氮化碳负载铂催化剂的制备、表征及对肉桂醛加氢的催化性能

Preparation and Characterization of Carbon Nitride Supported Pt Catalyst and Its Catalytic Performance on Hydrogenation of Cinnamaldehyde

通过尿素的高温聚合制备了片层状氮化碳g-C3N4,采用乙二醇还原法载铂得到Pt/g-C3N4催化剂。以X射线衍射(XRD)、X射线光电子能谱(XPS)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、傅里叶变换红外光谱(FT-IR)、比表面与孔隙度分析和电感耦合等离子体原子发射光谱(ICP-AES)等对所制备催化剂进行了表征,并在肉桂醛加氢反应中考察了其催化性能。结果表明,载体g-C3N4含有大量的含N基团,能有效稳定金属纳米粒子;Pt纳米粒子均匀分散在g-C3N4表面,且Pt粒径在2~3 nm之间;载体煅烧温度对催化剂的择性加氢性能有明显影响,550℃煅烧后的g-C3N4,所负载Pt在较温和的条件下表现出较明显的活性,肉桂醛转化率为30%,肉桂醇选择性为66%左右。重复使用3次,催化剂活性基本不变,具有良好的稳定性。

Layered carbon nitride g-C3N4 was prepared through high temperature polymerization of urea, and highly dispersive Pt nanoparticles were loaded onto g-C3N4 by ethylene glycol reduction to fabricate Pt/g-C3N4 catalyst. The catalyst was characterized using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier-transform infrared (FTIR) spectroscopy, surface area/porosity analysis and inductively coupled plasma atomic emission spectrometer (ICP-AES), and tested in the hydrogenation of cinnamelaldehyde. The results indicated that the support contains a large amount of N-containing groups which help to stabilize metal nanoparticles effectively;Pt nanoparticles uniformly dispersed in the surface of the g-C3N4 and its size is between 2 - 3 nm;the calcination temperature in g-C3N4 preparation had a significant effect on the performance of the catalyst for selective hydrogenation. Pt supported on g-C3N4 being calcinated at 550?C exhibited an appreciable activity, 30% conversion of cinnamic aldehyde and 66% selectivity for cinnamic alcohol under relatively mild condition. No obvious deterioration of the activity is observed after three times of usage, implying a good stability of the catalyst.