This study used experimental an‎d theoretical methods to investigate iron single-atom catalysts on different heteroatoms doped carbon supports. In the experimental section, an iron single-atom catalyst was synthesized on a nitrogen-doped 3D porous carbon support via a sodium chloride template. To eva‎luate the effect of secondary heteroatom dopants on catalytic activity, catalysts containing boron an‎d sulfur alongside nitrogen heteroatom were prepared. The presence of the iron single-atoms was confirmed using X-ray absorption spectroscopy. The catalysts were eva‎luated for thermal oxidative dehydrogenation of ethanol an‎d electrochemical oxygen reduction in alkaline media. In the oxidative dehydrogenation of ethanol, the catalyst without secondary heteroatom dopants exhibited the highest catalytic activity, achieving 40% ethanol conversion with high selec‎tivity toward acetaldehyde. The boron-doped catalyst exhibited the highest activity in the electrochemical oxygen reduction reaction, initiating at an onset potential of 0.91 V. In the theoretical section, the reaction mechanism of hydrogenation of carbon dioxide over iron, cobalt, an‎d nickel single-atom catalysts on nitrogen-doped graphene quantum dots was studied using density functional theory. The results showed that these catalysts facilitate the conversion of carbon dioxide to formic acid an‎d methanediol. The iron single-atom catalyst exhibited higher activity than the other catalysts. Natural bond orbital analysis revealed the essential role of nitrogen atoms in the reaction mechanism. Nitrogen activates hydrogen molecules for the reaction by donating electrons to the antibonding orbital of hydrogen.

سياوش كاظمي موحد

حسين فرخ پور

حسين توكل , عليرضا نجفي چرمهيني