CAJ | 학술논문

采用DFT+U方法研究了过渡金属替代的CeO2(111)表面上的NO+CO反应机理,以探求不同过渡金属对N2选择性的影响。结果表明,在反应过程中,反应活性中心由过渡金属单原子与其最近邻的氧空位组成。 NO在过渡金属-氧空位上发生N–O断键,不同过渡金属上该还原步骤的难易程度不同。计算发现,右过渡金属Rh, Pd和Pt替代的CeO2(111)表面可以与吸附物之间形成较强的吸附作用,进而可以达到较高的N2选择性。其主要原因是右过渡金属具有较多的d电子,可以与吸附小分子之间形成有效的反馈键。而左过渡金属拥有较少的d电子,难以有效抓住吸附物,最终导致较低的N2选择性。
채용DFT+U방법연구료과도금속체대적CeO2(111)표면상적NO+CO반응궤리,이탐구불동과도금속대N2선택성적영향。결과표명,재반응과정중,반응활성중심유과도금속단원자여기최근린적양공위조성。 NO재과도금속-양공위상발생N–O단건,불동과도금속상해환원보취적난역정도불동。계산발현,우과도금속Rh, Pd화Pt체대적CeO2(111)표면가이여흡부물지간형성교강적흡부작용,진이가이체도교고적N2선택성。기주요원인시우과도금속구유교다적d전자,가이여흡부소분자지간형성유효적반궤건。이좌과도금속옹유교소적d전자,난이유효조주흡부물,최종도치교저적N2선택성。
We present here a density functional theory plus U study of NO reduction with CO, catalyzed by a single transition metal atom (TM1=Zr1, Tc1, Ru1, Rh1, Pd1, Pt1)‐doped CeO2(111). The catalytic cen‐ter was identified as the TM dopant in combination with lattice oxygen. The investigation into N2 selectivity focused on three key elementary steps: gaseous N2O formation, subsequent re‐adsorption, and N–O bond scission to produce N2. In these steps, Rh1, Pd1, and Pt1/CeO2(111) exhibit a higher selectivity, whereas the other systems (Zr1, Tc1, Ru1) TM1/CeO2 show a lower selec‐tivity. The higher selectivity displayed by Pt1, Pd1, and Rh1 dopants arises from the availability of valence d electrons, which permit the formation of strong chemical bonds with the reactants and intermediates. Calculated results agree well with experimental findings, and the insights gained can be used to guide the rational design of the doped oxides for catalysis.