Effects of Molybdenum Doping on the Enhanced Electrocatalytic Nitrogen Reduction Reaction Performance of CeO2 Nanorods: Theoretical and Experimental Investigations.

Abstract

As a green and sustainable strategy, the electrocatalytic N2 reduction reaction (NRR) has been considered the best potential approach to replace the traditional Haber-Bosch process under ambient conditions. The key is to exploit efficient and low-cost electrocatalysts according to the current situation. Herein, a series of Molybdenum (Mo) doped CeO2 nanorods (NR) catalysts were successfully fabricated via a hydrothermal reaction coupled with high temperature calcination. The nanorod structures were not altered after Mo atom doping. The obtained 5 %-Mo-CeO2 nanorods act as a superior electrocatalyst in neutral electrolytes of 0.1 M Na2 SO4 . Such electrocatalyst significantly enhances NRR performance with an NH3 yield of 10.9 μg h-1 mg-1 cat at -0.45 V vs reversible hydrogen electrode (RHE) and a Faradaic efficiency (FE) of 26.5 % at -0.25 V vs RHE. That outcome is 4 times higher than that of CeO2 nanorods (2.6 μg h-1 mg-1 cat ; 4.9 %). Meanwhile, density functional theory (DFT) calculation shows the characteristics after Mo doping: the band gap value lowers, the density of states increases, electrons are more easily excited, and N2 molecules are more easily adsorbed, thereby enhancing the activity of the electrocatalytic NRR.