Direct conversion of N 2 and O 2 : status, challenge and perspective.

As key components of air, nitrogen (N 2 ) and oxygen (O 2 ) are the vital constituents of lives. Synthesis of NO 2 , and C-N-O organics direct from N 2 and O 2 , rather than from an intermediate NH 3 (known as the Haber-Bosch process), is tantalizing. However, the extremely strong N≡N triple bond (945 kJ mol -1 ) and the nonpolar stable electron configuration of dinitrogen lead to its conversion being extensively energy demanding. The further selective synthesis of high-value C-N-O organics directly from N 2 , O 2 and C-containing molecules is attractive yet greatly challenging from both scientific and engineering perspectives. Enormous efforts have been dedicated to the direct conversion of N 2 and O 2 via traditional and novel techniques, including thermochemical, plasma, electrochemical, ultrasonic and photochemical conversion. In this review, we aim to provide a thorough comprehension of the status and challenge of the direct conversion of N 2 , O 2 and C-containing molecules (particularly N 2 and O 2 ). Moreover, we will propose some future perspectives to stimulate more inspiration from the scientific community to tackle the scientific and engineering challenges.