The scalable growth of palladium nanosheets faces important challenges because they are highly sensitive to contamination and their synthesis requires specialized equipment. In addition, palladium nanosheets are usually synthesized in the gas phase using carbon monoxide, which involves the direct handling of this toxic and potentially hazardous gas. Minoru Osada and colleagues present an environmentally friendlier, one-pot method for the synthesis of pure palladium nanosheets. 2,4,6-Trichlorophenyl formate (TCPF) is used as the organic source of carbon monoxide, and the generation of CO gas from TCPF is driven by the emission of ammonia from urea. The generated CO gas serves a dual role, first reducing palladium ions into metallic palladium, and then acting as a surface capping agent. Adsorbed CO molecules onto growing Pd nanosheets help stabilize and control the growth, ensuring that it occurs in a 2D anisotropic fashion to enable the formation of flat nanosheets with a specific morphology.