Ultra-small Mo-Pt subnanoparticles enable CO 2 hydrogenation at room temperature and atmospheric pressure.

We present a partially-oxidised bimetallic Mo-Pt subnanoparticle (Mo 4 Pt 8 O x ) enabling thermally-driven CO 2 hydrogenation to CO at room temperature and atmospheric pressure. A mechanistic study explained the full catalytic cycle of the reaction from CO 2 activation to catalyst reactivation. DFT calculations revealed that alloying with Mo lowers the activation barrier by weakening the CO adsorption. This finding could be a first step for low-energy CO 2 conversion.