Ammonia synthesis from nitrogen oxides (NOx) offers a promising alternative to conventional N2–H2 processes by bypassing the energy challenge of N≡N bond cleavage while simultaneously processing major air pollutants. This review outlines our recent progress in the NOx-To-Ammonia (NTA) reaction using CO or H2 as a reductant. Catalysts based on Pt/TiO2, Cu/CeO2, and Ni/CeO2 revealed distinct mechanistic pathways involving formate and isocyanate (NCO) intermediates rather than direct NO reduction. Optimization of the TiO2 crystalline phase and preparation improved Pt dispersion and boosted activity. Cu/CeO2 achieved good low-temperature performance without requiring precious metals. Ni/CeO2 and bimetallic Ni–Pt/TiO2 catalyzed an NCO-mediated route. Moreover, partially reduced Pt/TiO2–δ nearly eliminated N2O byproducts. These advances demonstrate that rational catalyst design targeting key intermediates enables selective low-temperature ammonia synthesis from NOx, so promoting a sustainable strategy for energy-efficient nitrogen utilization.
Manaka et al. (Sat,) studied this question.