Fabricating Lattice-Confined Pt Single Atoms With High Electron-Deficient State for Alkali Hydrogen Evolution Under Industrial-Current Density.

The confining effect is essential to regulate the activity and stability of single-atom catalysts (SACs), but the universal fabrication of confined SACs is still a great challenge. Here, various lattice-confined Pt SACs supported by different carriers are constructed by a universal co-reduction approach. Notably, Pt single atoms confined in the lattice of Ni(OH) (Pt/Ni(OH)) with a high electron-deficient state exhibit excellent activity for basic hydrogen evolution reaction (HER). Specifically, Pt/Ni(OH) just requires 15 mV to get 10 mA cm and the mass activity of Pt/Ni(OH) is 15 times of commercial Pt/C. Moreover, Pt/Ni(OH) assembled in an alkaline water electrolyzer shows 1030 h durability under the industrial current density of 800 mA cm. In situ spectroscopy techniques reveal Pt─H and "free" OH radical can be directly observed for Pt/Ni(OH), confirming the lattice-confined Pt single atoms play a key role during HER. Further density functional theory uncovers the Pt 3d orbital strongly hybridizes with O 2p and Ni 3d orbitals in Ni(OH), which quickly optimizes the electronic state of the Pt site, thus largely reducing the energy barrier of the rate-determining step to 0.16 eV for HER. Finally, this synthesis method is extended to construct other 9 lattice-confined SACs.