Blocking the non-selective sites through surface plasmon-induced deposition of metal oxide on Au/TiO2 for CO-PROX reaction

doi:10.1016/j.checat.2021.04.003

Chem Catalysis

Volume 1, Issue 2, 15 July 2021, Pages 456-466

https://doi.org/10.1016/j.checat.2021.04.003 Get rights and content

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Highlights

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Photoexcited deposition of metal oxide method is employed for interface engineering
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Interface-engineered Au-TiO₂ helps to identify the active site in CO and H₂ oxidation
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Blocking the non-selective sites greatly improves the CO-PROX performance
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Interface anchoring with inert lead oxide enhances long-term thermal stability

The bigger picture

Against the background of the carbon-neutral era, the liquid sunshine industry is booming due to the consumption of greenhouse gas (CO₂) and the solution of storage and transportation of H₂ energy. However, before the terminal application of H₂ energy, CO must be removed in the H₂-rich reformate to avoid poisoning the noble metal catalysts. Gold-catalyzed CO preferential oxidation (PROX) has great potential in the removal of CO from H₂-rich reformate. The competition oxidation of CO and H₂ at the interface of gold support always results in a decrease in CO oxidation conversion and selectivity, especially at high temperature. However, it is a major challenge to distinguish the interfacial sites from the other parts of nanoparticle surface. We show here that the interface of Au-TiO₂ is modified by our photoexcited deposition of metal oxide (PDMO) method, which greatly affects the performance of the CO-PROX reaction.

Summary

CO preferential oxidation (PROX) in excess hydrogen is a promising strategy for CO removal in hydrogen-rich reformate. However, the CO conversion and CO₂ selectivity in the PROX reaction dramatically decrease with rising temperature, resulting in a major challenge to complete CO removal across a wide temperature window. Here, we developed a photoexcited deposition of metal oxide (PDMO) method based on surface plasmonic resonance of Au nanoparticles, which can tune the interfacial properties by depositing lead oxide at the Au-TiO₂ interface. The interface modified Pb₃O₄/Au/TiO₂ catalyst can successfully eliminate CO in a wide temperature range (70°C–140°C) and exhibit superior stability in the PROX reaction. Further experiments demonstrated that the improved PROX performance is due to the severely depressed hydrogen oxidation through simultaneously inhibiting the activation of hydrogen and oxygen. The results further reveal that the interface of Au/TiO₂ is the superactive but non-selective site for H₂ and CO oxidation.

Graphical abstract

Keywords

gold catalysis

interface engineering

CO-PROX reaction

surface plasmon

selective photodeposition

UN Sustainable Development Goals

SDG9: Industry, innovation, and infrastructure

SDG7: Affordable and clean energy

Cited by (0)

⁹: These authors contributed equally

¹⁰: Lead contact