Precisely-controlled synthesis of Au@Pd core–shell bimetallic catalyst via atomic layer deposition for selective oxidation of benzyl alcohol

• Precise synthesis of Au@Pd core–shell bimetallic catalyst with selective Pd ALD.
• Monometallic particle formation was avoided during bimetallic catalyst synthesis.
• Precisely tuning the Pd shell thickness by varying the number of Pd ALD cycles.
• Catalytic activities showed a volcano-like trend with the Pd shell thickness.
• Selective metal ALD is general for other core–shell bimetallic particle synthesis.

In this study, we report a novel facile strategy for atomically-precise synthesis of supported Au@Pd core–shell bimetallic catalyst via atomic layer deposition (ALD). By choosing a proper deposition condition, we can selectively deposit Pd only on Au nanoparticle surface, but not on SiO2 support to exclusively form Au@Pd core–shell bimetallic nanoparticles, while avoiding monometallic nanoparticle formation; therein, the Pd shell thickness can be atomically precisely tuned by varying the number of Pd ALD cycles. In solvent-free oxidation of benzyl alcohol, the catalytic activities of the resulted Au@Pd/SiO2 core–shell bimetallic catalysts showed a clear volcano-like trend with the Pd shell thickness, reaching a maximum at a Pd shell thickness of 0.6–0.8 nm due to the optimized synergistic effect. More importantly, we believe this new strategy of precise synthesis of core–shell structured bimetallic catalyst using ALD can be general to other supported bimetallic catalysts for broad applications.

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