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

Abstract

Abstract 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 μmmol g −1 h −1 ) than Pt nanoparticles on CN (3192 μmmol 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.

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