In situ formation of cocatalytic sites boosts single-atom catalysts for nitrogen oxide reduction.

Nitrogen oxide (NO x ) pollution presents a severe threat to the environment and human health. Catalytic reduction of NO x with H 2 using single-atom catalysts poses considerable potential in the remediation of air pollution; however, the unfavorable process of H 2 dissociation limits its practical application. Herein, we report that the in situ formation of Pt Ti cocatalytic sites (which are stabilized by Pt-Ti bonds) over Pt 1 /TiO 2 significantly increases NO x conversion by reducing the energy barrier of H 2 activation. We demonstrate that two H atoms of H 2 molecule are absorbed by adjacent Pt atoms in Pt-O and Pt-Ti, respectively, which can promote the cleave of H-H bonds. Besides, Pt Ti sites facilitate the adsorption of NO molecules and further lower the activation barrier of the whole de-NO x reaction. Extending the concept to Pt 1 /Nb 2 O 5 and Pd 1 /TiO 2 systems also sees enhanced catalytic activities, demonstrating that engineering the cocatalytic sites can be a general strategy for the design of high-efficiency catalysts that can benefit environmental sustainability.