Progress on nano- to atom-size dual-metal-site catalysts (DMSC) for enhanced dry reforming of methane with carbon dioxide

Currently, the goals of carbon peaking and carbon neutrality are driving the development of cutting-edge technologies to recover CO2 and further close the carbon cycle. Among them, dry reforming of methane (DRM) is considered one of the most promising processes as it can reduce the release of CO2 and CH4 while producing syngas from H2 and CO, which can be further processed into valuable chemicals through Fischer-Tropsch synthesis. Numerous studies have been conducted on catalyst design for DRM processes. Conventional single-metal site catalysts (SMSCs) still need to promote catalytic activity, which is hindered by carbon deposition and sintering of the active metal. Fortunately, dual-metal-site catalysts (DMSCs), including nano-sized and even atomic-sized catalysts, are attracting the interest of researchers due to their resistance to carbon deposition, prevention of active metal aggregation, strong metal-support interaction (SMSI), etc. Proposed methods for improving catalytic efficiency and durability are outlined. DMSCs, with their precisely structured and tailored design, offer valuable opportunities for fundamental studies aimed at understanding the governing mechanisms and active sites in CO2-CH4 reforming reactions. In this review, we provide an overview of recent research developments in catalysts for CO2-CH4 reforming reactions, including nano- and atom-size catalysts. The key content includes catalyst design strategies (e.g., promoter doping, support modification, defect regulation), and synthesis methods (e.g., calcination temperatures, and reduction treatment), performance modulation (e.g., CO2/CH4 conversion efficiency and CO/H2 molar ratio), and reaction mechanism exploration. By covering a large number of studies on DMSCs, we aim to provide a more comprehensive and general understanding of the state of the art in DMSCs and also highlight potential development directions for future studies on heterogeneous catalysis of DRM in DMSC systems, in the hope of advancing not only fundamental experiments but also practical applications of DRM to one day alleviate the energy and environmental crisis caused by the misuse of fossil fuels and the resulting greenhouse effects.