Nanoscale Self-Wetting Driven Monatomization of Ag Nanoparticle for Excellent Photocatalytic Hydrogen Evolution

Metal nanoparticles (NPs) with <10 nm have demonstrated many novel applications including surprisingly low melting point, astonishing liquid-like pseudoelasticity, and outstanding hydrogen evolution performance. Here, a nanoscale self-wetting driven monatomization of Ag NPs with <5 nm on carbon nitride (CN) to fabricate Ag single-atom catalyst (Ag-1/CN SAC) is demonstrated, and a thermodynamic approach to elucidate Ag NPs decomposing into single atoms is established. Dynamic dispersion process of Ag NPs into atoms on CN is recorded using in situ AC-HADDF-TEM techniques. Density functional theory calculations and molecular dynamics simulations suggest that the spontaneous dispersion origins from the nanoscale self-wetting effect in thermodynamics. In atomic scale, the driving force of self-wetting derived from the balance between cohesive energy of Ag NPs and excess energy of Ag atoms in CN vacations. The fabricated Ag-1/CN SAC proved a higher efficiency for photocatalytic hydrogen evolution activity (3690 mu mmol g(-1) h(-1)) than Pt nanoparticles on CN (3192 mu mmol g(-1) h(-1)). This spontaneous monatomization resulting from the interaction between metal NPs and substrate provides a simple method to prepare SACs with a high active photocatalytic hydrogen evolution.

Automated summary

The study demonstrates the fabrication of Ag single-atom catalyst (Ag-1/CN SAC) on carbon nitride (CN) through a nanoscale self-wetting driven monatomization of Ag nanoparticles (NPs) with <5 nm. The spontaneous dispersion of Ag NPs into single atoms on CN originates from the nanoscale self-wetting effect in thermodynamics. The Ag-1/CN SAC exhibits higher photocatalytic hydrogen evolution activity than Pt nanoparticles on CN.