Insight into alloy and single-atom alloy catalysts for CO2 to CH4 conversion

Alternative energy sources are becoming increasingly prominent due to the environmental consequences of fossil fuel consumption, accelerating the transition toward efficient, low-carbon, and secure energy systems. Addressing CO 2 emissions through efficient catalytic processes is essential to achieving the United Nations Sustainable Development Goals (SDGs), particularly SDG 13 (Climate Action) and SDG 7 (Affordable and Clean Energy). Among available carbon utilization strategies, CO 2 methanation provides a viable pathway to convert this greenhouse gas into methane (CH 4 ), a clean synthetic fuel compatible with existing natural gas infrastructures. Additionally, it supports Power-to-Gas technologies, enabling renewable energy storage as methane to address energy intermittency challenges. Recent studies have shown that alloy catalysts and single-atom alloys (SAAs) can improve CO 2 methanation performance through modifications of electronic structure, adsorption behaviour, and metal–support interactions. Despite considerable progress, understanding the relationships between catalyst structure, reaction pathways, and catalytic performance remains an active area of research. This review provides an overview of recent advances in alloy and SAAs catalysts for CO 2 -to-CH 4 conversion, covering structural and electronic characteristics, metal–metal and metal–support interactions, reaction mechanisms, synthesis strategies, stability enhancement approaches, and advanced characterization techniques. Particular attention is given to the influence of alloying and single-atom incorporation on catalytic activity and methane selectivity. By integrating recent advances with fundamental catalytic principles, this review highlights current challenges and opportunities in catalyst design and outlines future directions for the development of efficient and durable catalysts for sustainable CO 2 methanation.