Artificial photocatalytic nitrogen fixation: Where are we now? Where is its future?

In this Perspective, we summarize recent advancements in photocatalytic nitrogen fixation since 1977, placing particular emphasis on the smart photocatalysts and reaction system design strategies, and also the quantification of products (e.g., NOx, nitrate and ammonia) in photocatalytic N2 fixation experiments. We start with exploring fundamental aspects of N2 photofixation, ranging from N2 adsorption and activation, then N2 fixation processes. Subsequently, we review the most appropriate test methods for ammonia quantification under particular testing conditions (thus avoiding the reporting of high yet erroneous NH3 yield). Further, an objective snapshot of the field as it currently stands is offered to researchers regarding the urgent need of a reliable and rigorous evaluation criteria, advanced photocatalysts and reaction system for maximizing photocatalytic performance together with the added value of the products, laying a firm platform for future photocatalytic nitrogen fixation technology development