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.