Ammonia serves as a viable medium for hydrogen storage owing to its significant hydrogen content and elevated energy density, and the absence of carbon dioxide emissions during ammonia-to-hydrogen production has inspired more research on ammonia decomposition. Despite growing interest, a significant gap persists between the depth of existing studies and the practical approach to on-the-spot hydrogen generation using ammonia decomposition. The creation of effective and accessible catalysts to feed ammonia decomposition is a critical step in addressing this daunting challenge. This paper systematically summarizes four key catalyst design strategies, including size effect, alkalinity modulation, metal–support interactions, and alloying, informed by experimental and theoretical investigations into ammonia decomposition. Each strategy's underlying mechanism for enhancing ammonia decomposition is elucidated in detail. Moreover, the paper categorizes catalysts employed in existing ammonia decomposition reactors to guide future catalyst development. The influence of diverse energy sources and reactor configurations on catalyst performance is also discussed to provide a comprehensive framework for advancing ammonia decomposition catalyst research.

In recent years, with increasingly scarce land resources, incineration technology has gradually become the mainstream disposal method of household hazardous waste. The exhaust gas of incineration contains both NO_x and chlorine-containing volatile organic compounds (CVOCs), which will cause air pollution and serious harm to human health. The synergetic purification of NO_x and CVOCs has huge ecological environment and economic benefits. Therefore, it is necessary to design a dual-effect catalyst to eliminate NO_x and CVOCs simultaneously. In this work, we prepared CeO₂-based catalysts doped with different metal cations by co-precipitation method. The physical and chemical properties of the catalysts were characterized by a variety of characterization methods. The catalytic activity of the catalysts for the synergistic oxidation of chlorobenzene and reduction of NO_x was evaluated, and the reaction mechanism was explored. We found that Cr–Ce sample showed good synergistic catalytic activity and stability. The strong redox performance of Cr species not only improved the NO_x reduction and CVOC oxidation capacity of CeO₂, but also solved the problem of chlorination poisoning of pure CeO₂.