Noble-Metal-Free Single- and Dual-Atom Catalysts for Artificial Photosynthesis

Artificial photosynthesis enables direct solar-to-chemical energy conversion aimed at mitigating environmental pollution and producing solar fuels and chemicals in a green and sustainable approach, and efficient, robust, and low-cost photocatalysts are the heart of artificial photosynthesis systems. As an emerging new class of cocatalytic materials, single-atom catalysts (SACs) and dual-atom catalysts (DACs) have received a great deal of current attention due to their maximal atom utilization and unique photocatalytic properties, whereas noble-metal-free ones impart abundance, availability, and cost-effectiveness allowing for scalable implementation. This review outlines the fundamental principles and synthetic methods of SACs and DACs and summarizes the most recent advances in SACs (Co, Fe, Cu, Ni, Bi, Al, Sn, Er, La, Ba, etc.) and DACs (CuNi, FeCo, InCu, KNa, CoCo, CuCu, etc.) based on non-noble metals, confined on an arsenal of organic or inorganic substrates (polymeric carbon nitride, metal oxides, metal sulfides, metal-organic frameworks, carbon, etc.) acting as versatile scaffolds in solar-light-driven photocatalytic reactions, including hydrogen evolution, carbon dioxide reduction, methane conversion, organic synthesis, nitrogen fixation, hydrogen peroxide production, and environmental remediation. The review concludes with the challenges, opportunities, and future prospects of noble-metal-free SACs and DACs for artificial photosynthesis.

Automated summary

Artificial photosynthesis aims to convert solar energy into chemical energy, mitigate environmental pollution, and produce sustainable solar fuels and chemicals. The key to artificial photosynthesis systems is efficient, robust, and low-cost photocatalysts. Single-atom catalysts (SACs) and dual-atom catalysts (DACs) have gained significant attention due to their unique photocatalytic properties, while noble-metal-free catalysts offer abundance, availability, and cost-effectiveness for scalable implementation. This review outlines the principles, synthesis methods, and recent advances in SACs and DACs based on non-noble metals, using organic or inorganic substrates as scaffolds in solar-light-driven photocatalytic reactions. The review concludes with discussing the challenges, opportunities, and future prospects of noble-metal-free SACs and DACs for artificial photosynthesis.