A simple preparation procedure converts ultrathin sheets of titanium carbide to a material that supports isolated platinum atoms, yielding a highly active catalyst that uses CO2, a greenhouse gas, to make valuable organic compounds (J. Am. Chem. Soc. 2019, DOI: 10.1021/jacs.8b13579). A common procedure for preparing MXenes, a family of 2-D metal carbides and nitrides, from mixed-metal carbide starting materials yields a related carbide dotted with individual titanium vacancies. Chen Chen of Tsinghua University and coworkers proposed that treating the defective material with a platinum salt would be an easy way to pin isolated platinum atoms across the MXene surface. So the researchers prepared the material, confirmed its structure, and tested its ability to catalyze reactions. They found that it was especially effective at mediating formylation of many types of amines with CO2 under mild conditions. For example, exposing aniline to CO2 at atmospheric pressure in the presence of the catalyst and a silane reductant produced N-phenyl formamide (shown) with a yield and selectivity of nearly 100%, far higher than that obtained using reference platinum catalysts. Analyses show that a small positive charge on the platinum atom (Ptδ+) contributes to catalytic performance by facilitating adsorption of reagent molecules.