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 non-noble metal-based SACs (Co, Fe, Cu, Ni, Bi, Al, Sn, Er, La, Ba, etc.) and DACs (CuNi, FeCo, InCu, KNa, CoCo, CuCu, etc.) 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. This review concludes with the challenges, opportunities and future prospects of noble metal-free SACs and DACs for artificial photosynthesis. This article is protected by copyright. All rights reserved.