We accomplished efficient electrocatalytic low-temperature ammonia synthesis with the highest yield reported to date.

No abstract

Detailed reaction mechanisms for the oxidative coupling of methane (OCM) over Ce 2 (WO 4 ) 3 catalysts at low temperatures in an electric field were investigated. The influence of Ce cations in the Ce 2 (WO 4 ) 3 catalyst was evaluated by comparing the OCM activity over various Ln 2 (WO 4 ) 3 (Ln = La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, and Dy) catalysts in an electric field. The electronic states of Ln and W cations and the relationship between the distorted Ce 2 (WO 4 ) 3 structure and methane activation were examined using X-ray absorption fine structure (XAFS) measurements and first-principles calculations. The results reveal that the Ln 2 (WO 4 ) 3 catalysts with redoxactive Ln cations (Ce, Pr, Sm, Eu, and Tb) show OCM activity. First-principles calculations indicate that Ce 3+ species in the Ce 2 (WO 4 ) 3 structure are oxidized to Ce 4+ species in an electric field by extracting electrons from the Ce 4f orbitals near the Fermi level; as a result, its structure is distorted. The results indicate that the redox reaction of Ln cations in Ln 2 (WO 4 ) 3 induced by an electric field brings lattice strain and a high OCM activity in an electric field.