Research Of Hydrothermal Modification Of Activated Carbon Of Pd/AC Catalysts

In this thesis, the effect of hydrothermal conditions on the catalytic performance of 0.5% Pd/AC catalyst was studied. The influence of HNO3 concentration, hydrothermal temperature and hydrothermal time on the support structure, surface oxygen functional groups (SOFGs), Pd particle size was studied. And the catalytic of Pd/AC catalyst was investigated by N2 physisorption, NH3-TPD, FTIR, TG, XPS and TEM. In addition, the hydrothermal reaction conditions were optimized. The results were listed as follows:1. The amount of SOFGs increases with the concentrations of nitric acid,the Pd particle size decreased firstly and then increased,and the catalytic performance of Pd/AC catalyst increased firstly and then decreased. The porous texture of carbon support almost keep unchanged with low HNO3 concentrations (?1.5 mol·L-1) treatment,while it decreases significantly at high acid concentrations (2.0 mol·L-1). The optimal conditions of hydrothermal treatment are HNO3 (1.0 mol·L-1) at 150 ? for 4 h, and the formic acid decomposition rate reached 92.2%.2. With the increase of hydrothermal temperature, the SOFGs and the catalytic performance of Pd/AC catalyst increased firstly and then decreased, the Pd particle size decreased firstly and then increased. The porous texture of carbon support decreased significantly at high hydrothermal temperature (190 ?). The optimal conditions of hydrothermal treatment are HNO3 (1.0 mol·L-1) at 150 ? for 4 h, and the formic acid decomposition rate reached 92.2%.3. With the increase of hydrothermal time, the SOFGs and the catalytic performance of Pd/AC catalyst increased firstly and then decreased, the Pd particle size decreased firstly and then increased. The porous texture of carbon support decreased significantly at long hydrothermal time (12 h). The optimal conditions of hydrothermal treatment are HNO3 (1.0 mol·L-1) at 150 ? for 4 h,and the formic acid decomposition rate reached 92.2%.