Atomic Ru clusters supported on CeO2(110) for effectively catalyzing the electrochemical N2 reduction reaction: insights from density functional theory†
Abstract
In this work, density-functional theory (DFT) was used to investigate the geometry and electronic structure of Run(n = 1–6,10) supported on CeO2(110) (Run(n = 1–6,10)/CeO2(110)) and their electrocatalytic properties for the N2 reduction reaction (NRR). The results indicated that there is a strong metal–support interaction between Run and CeO2(110), which leads to large surface distortion and stabilized Run. On Run(n = 1–6,10)/CeO2(110), N2 captured in the end-on mode is thermodynamically more favorable than that captured in the side-on mode; however, the side-on mode can lead to stronger activation of N2 which promotes the following protonation step of N2. For Run(n = 3,5,6)/CeO2(110), the electrochemical NRR prefers to occur via an enzymatic mechanism with limiting potentials of −0.31, −0.53 and −0.66 V. The electrocatalytic activity of Run(n = 1–6,10)/CeO2(110) for the NRR shows a strong size dependence. For Ru3/CeO2(110), it has the lowest absolute value of limiting potential, and with the increase in n (n > 3), the limiting potential becomes more negative. Moreover, Ru3/CeO2(110) shows high selectivity and stability. This study gives valuable insights for designing effective catalysts for the NRR.