Recent insights on Z-scheme and S-scheme photocatalysts for nitrogen conversion to ammonia: A review

One of the main research hot spots of the present century is the design and development of technologies for producing ammonia with minimal environmental impacts and energy-efficient procedures. Recently, the utilization of heterogeneous photocatalysts for nitrogen fixation has attracted the booming opinion of researchers, as it is a practical, environmentally friendly, and sustainable approach for ammonia synthesis. Integrating two or more semiconductors and developing heterojunctions with Z/S-scheme mechanism is a suitable solution for promoting the photocatalytic nitrogen fixation efficiency. The Z/S-scheme photocatalysts could effectually improve the segregation of charges, retain the reducing/oxidizing power of electrons/holes, and significantly boost harvesting of the solar energy. Therefore, the overall objective of this review is to provide an overview of recent research papers on Z/S-scheme photocatalytic systems and to establish a strong foundation to ensure successful progress in the promising field of nitrogen fixation research. Hence, the detailed reaction mechanism with Z/S-scheme systems, charge kinetics, and reaction pathways are highlighted. Moreover, the structural/electronic features, synthesis routes, and photocatalytic performance in the nitrogen fixation are summarized. The challenges in the arena and perspectives on the future progress of photocatalytic nitrogen fixation are introduced too. This review provide an extensive and inspiring picture for the rationally designing impressive Z/S-scheme photocatalysts for production of ammonia in large scale.