Year: 2025
Type: article
Abstract: With the continuous growth of global energy demand and the increasingly severe environmental challenges, the development of clean and sustainable alternative energy sources has become a key priority for countries worldwide. Ammonia (NH3), as one of the most important basic chemical raw materials and a potential clean energy carrier, plays a crucial role in supporting agricultural production and industrial development. Nitrogen (N2), one of the most abundant inert molecules in the atmosphere, requires a substantial amount of energy and efficient catalysts to be reduced to NH3. Since the early 20th century, the Haber-Bosch process has dominated industrial NH3 production, where iron-based catalysts synthesize NH3 from N2 and H2 under high temperature (350–450℃) and high pressure (150–200 atm). However, this process is highly energy-intensive, consuming about 2% of the world’s total energy supply and contributing to over 1% of global carbon emissions. These significant energy and environmental costs raise concerns about the sustainability of the Haber-Bosch process. Despite efforts to develop new coal chemical and H2 production technologies to improve energy efficiency and reduce carbon emissions, the issues of high energy consumption and pollution remain largely unresolved. As a result, there has been increasing interest in exploring alternative methods for N2 reduction that are mild, efficient, and sustainable. This has greatly stimulated research focused on achieving efficient N2 reduction to synthesize NH3 under mild conditions. The high-efficiency N2 fixation achieved by nitrogenases under ambient conditions has inspired researchers to study the structure and electronic properties of these enzymes to design efficient and stable artificial N2 fixation catalysts. Natural nitrogenases are capable of reducing N2 to NH3 under mild conditions with high efficiency and selectivity, offering valuable insights for the development of artificial systems. In recent years, significant progress has been made in the field of artificial photosynthetic N2 fixation, driven by the deep study of the structural and functional features of nitrogenase active sites. The weak adsorption and interaction between N2 and catalyst surfaces require innovative catalyst design. Researchers have conducted in-depth analyses of the thermodynamic and kinetic challenges associated with N2 reduction, focusing on understanding the mechanisms and principles behind N2 activation. Based on these insights, they have designed various homogeneous molecular and heterogeneous N2 reduction catalysts. With gradually understanding the active sites and electron transfer pathways of nitrogenase enzymes, these catalysts aim to effectively utilize renewable energy sources, such as solar energy, to enhance both the efficiency and selectivity of the N2 fixation process. This review summarizes the recent advancements in artificial photosynthetic N2 fixation, focusing on the thermodynamic and kinetic challenges as well as the catalytic mechanisms involved. It highlights the design principles and associated challenges of both homogeneous and heterogeneous N2 fixation catalysts, providing a comprehensive overview of the field. Furthermore, the work identifies the key obstacles facing current developments and proposes potential solutions. With the continuous progress of artificial photosynthetic N2 fixation technologies, it is anticipated that these systems will offer sustainable nitrogen-containing industrial products synthesis solutions such as NH3, urea, and amines. The rational design of efficient homogeneous and heterogeneous catalysts holds great promise for achieving artificial nitrogen cycling and may lead to transformative changes in the energy and agricultural industries. By using more efficient energy and reducing environmental impact, artificial N2 fixation will play a pivotal role in addressing global food security and energy sustainability challenges.
DOI: 10.1360/tb-2025-0004
Authors: De-Shan Zhang, Yong-Peng Liang, Yu Yang, Chen-Ho Tung, Li-Zhu Wu
Language: English
Subfield: Catalysis
Field: Chemical Engineering
Domain: Physical Sciences
Open Access status: bronze
OpenAlex ID: W4407633490