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.