Five Rare Earths in One Catalyst Turn Methane Into Plastics Feedstock

A group at Institute of Science Tokyo has made a methane catalyst from five rare earth metals mixed into a single oxide, and reports that, in laboratory tests, it gave ethylene and ethane in about 12.3% total yield at temperatures below 600 °C and held its activity for 240 hours at 600 °C. The work was published on Oct. 8, 2026, in the Journal of the American Chemical Society.

Oxidative coupling, the reaction they ran, turns methane directly into ethylene and ethane, the feedstocks plastics are made from. It normally needs enough heat to wear a catalyst out, and the authors' case for mixing metals is that it keeps the surface chemistry stable while lowering the temperature the reaction starts at.

The catalyst is written (LaSmEuGdDy)0.4O3: lanthanum, samarium, europium, gadolinium and dysprosium share the same positions in one crystal instead of a single metal filling them, an arrangement chemists call a high-entropy oxide. The paper reports it was made by a sol-gel route, from the metals' acetate salts and an amino acid.

The authors report that, against oxides of the individual metals, the mixture began coupling methane at a lower temperature and lasted longer. Carbon dioxide desorption measurements tracked how strongly the surface binds an acidic gas, and they report that this strength can be set through the average size of the metal ions, producing the sites needed to break a carbon-hydrogen bond at low temperature.