Oxygen Vacancies of CeO 2 Nanospheres by Mn-Doping: An Efficient Electrocatalyst for N 2 Reduction under Ambient Conditions.

The electrochemical N ₂ reduction reaction (NRR) demonstrates a process of NH ₃ synthesis from N ₂ molecules under ambient conditions, which is environmentally friendly and recyclable. However, it requires an efficient electrocatalyst to activate inert N ₂ molecules, which is still difficult to satisfy. Recently, as an active NRR electrocatalyst and a typical metal oxide, CeO ₂ has featured ultrahigh thermal stability and the ability to apply heteroatom doping, which is an imperative approach importing oxygen vacancy by replacing metal ions with selective elements to greatly influence the activity of catalysts. Here, we analyze the unique properties of manganese dopants in modulating the activity of CeO ₂ nanospheres for NRR. It attains a larger NH ₃ yield of 27.79 μg h ^-1 mg _cat ^-1 and a higher Faradaic efficiency of 9.1% than pure CeO ₂ at -0.30 V in 0.1 M HCl, with high electrochemical and structure stability. With calculations by density functional theory, the performance enhancement of Mn-doped CeO ₂ is also proved mathematically.