Supported [Rh10Se] catalyst on TiO2 converted carbon dioxide into ethanol faster (60 × 10–3 mol h–1 g cat–1) and more selectively (≈83%) than other supported Rh clusters or [Rh10Se] on other inorganic oxides, presumably due to the effects of interstitial Se and the interface of the [Rh10Se] cluster and TiO2.