Methods for nitrogen activation by reduction and oxidation

The industrial Haber-Bosch process to produce ammonia (NH3) from dinitrogen (N-2) is crucial for modern society. However, N-2 activation is inherently challenging and the Haber-Bosch process has significant drawbacks, as it is highly energy intensive, is not sustainable owing to substantial CO2 emissions primarily from the generation of H-2 and requires large, centralized facilities. New strategies of sustainable N-2 activation, such as low-temperature thermochemical catalysis and (photo)electrocatalysis, have been pursued, but progress has been hindered by the lack of rigour and reproducibility in the collection and analysis of results. In this Primer, we provide a holistic step by step protocol, applicable to all nitrogen-transformation reactions, focused on verifying genuine N-2 activation by accounting for all contamination sources. We compare state-of-the-art results from different catalytic reactions following the protocol's framework, and discuss necessary reporting metrics and ways to interpret both experimental and density functional theory results. This Primer covers various common pitfalls in the field, best practices to improve reproducibility and cost-efficient methods to carry out rigorous experimentation. The future of nitrogen catalysis will require an increase in rigorous experimentation and standardization to prevent false positives from appearing in the literature, which can enable advancing towards practical technologies for the activation of N-2.