Junkaew Anchalee, Namuangruk Supawadee, Maitarad Phornphimon, Ehara Masahiro
National Nanotechnology Center (NANOTEC), National Science and Technology Development Agency (NSTDA) Pathum Thani 12120 Thailand
Research Center of Nano Science and Technology, Shanghai University Shanghai 200444 P. R. China.
RSC Adv. 2018 Jun 19;8(40):22322-22330. doi: 10.1039/c8ra03265c.
Metal-free catalysts for the transformation of NO and CO into green products under mild conditions have long been expected. The present work proposes using silicon-coordinated nitrogen-doped graphene (SiNG) as a catalyst for NO reduction and CO oxidation based on periodic DFT calculations. The reaction proceeds two steps, which are NO reduction at the Si reaction center, producing Si-O*, which subsequently oxidizes CO to CO. The NO reduction occurs with an activation energy barrier of 0.34 eV, while the CO oxidation step requires an energy of 0.66 eV. The overall reaction is highly exothermic, with a reaction energy of -3.41 eV, mostly due to the N generation step. Compared to other metal-free catalysts, SiNG shows the higher selectivity because it not only strongly prefers to adsorb NO over CO, but the produced N and CO are easily desorbed, which prevents the poisoning of the active catalytic sites. These results demonstrate that SiNG is a promising metal-free catalyst for NO reduction and CO oxidation under mild conditions, as the reaction is both thermodynamically and kinetically favorable.
长期以来，人们一直期待能有一种无金属催化剂，可在温和条件下将一氧化氮（NO）和一氧化碳（CO）转化为绿色产物。目前的工作基于周期性密度泛函理论（DFT）计算，提出使用硅配位氮掺杂石墨烯（SiNG）作为NO还原和CO氧化的催化剂。该反应分两步进行，首先在硅反应中心发生NO还原，生成Si - O*，随后Si - O*将CO氧化为CO₂。NO还原反应的活化能垒为0.34电子伏特（eV），而CO氧化步骤需要0.66 eV的能量。整个反应是高度放热的，反应能量为 - 3.41 eV，这主要归因于氮生成步骤。与其他无金属催化剂相比，SiNG表现出更高的选择性，因为它不仅强烈倾向于优先吸附NO而非CO，而且生成的N₂和CO₂易于脱附，从而防止活性催化位点中毒。这些结果表明，SiNG是一种在温和条件下用于NO还原和CO氧化的有前景的无金属催化剂，因为该反应在热力学和动力学上都是有利的。
