Revealing the Sudden Alternation in Pt@h-BN Nanoreactors for Nearly 100% CO2-to-CH4 Photoreduction

How to develop an efficient photocatalyst with high activity and high selectivity is the biggest challenge limiting the application of photocatalysis. A reasonable design of the nanoreactor model is an effective strategy. Herein, a series of Pt nanoparticles coated with hexagonal boron nitride (Pt@h-BN) nanoreactors highly dispersed on a photochemically inert carrier, Al2O3 substrate, are synthesized. The results show that as the number of h-BN coating layers increases, the selectivity of photocatalysis is altered from nearly 100% CO2-to-CO to nearly 100% CO2-to-CH4, and the optimized space-time yield of CH4 is up to 184.7 mu mol g((Pt))(-1) h(-1) with three-layer coating. The in situ characterizations reveal the cleavage of the CO on Pt to be the rate determining step and the existence of the key intermediate CO2- species on the surface of Pt@h-BN facilitates CH4 formation. Notably, combined with detailed simulation calculations, this work reveals that the confinement effect in Pt@h-BN attributes the electrons mobility behavior and alleviate the interaction of CO-Pt. What is more, the change of the reaction site is the essence for the sudden alternation. This work will bring a new insight to the selective catalysis of noble metals in the gas-solid phase.

Automated summary

This study focuses on the development of efficient photocatalysts with high selectivity through the synthesis of Pt@h-BN nanoreactors. Detailed experimental and simulation calculations reveal the confinement effect and the change in reaction sites play vital roles in the catalytic reaction process.