Heterogeneous catalysts for the sustainable production of hydrogen peroxide

Paris, Charlie 2023. Heterogeneous catalysts for the sustainable production of hydrogen peroxide. PhD Thesis, Cardiff University. Item availability restricted.

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Abstract

This thesis aims at developing new systems designed for the sustainable production of hydrogen peroxide. The first research chapter focuses on the clever catalyst design for the direct synthesis of H2O2. The sol immobilization method is a promising route for preparing well-dispersed supported metal nanoparticles, which are particularly suitable for the formation of H2O2. However, over the years, a general procedure has emerged overlooking the chemistry taking place during the catalyst preparation. This chapter demonstrates the importance of the preparation parameters on the final properties of the catalyst. In particular, the addition of acid should be tailored to the support-stabilizer combination. When acid is added to the sol, the electrostatic interactions between PAA-stabilized AuPd nanoparticles and carbon-based supports are altered, resulting in a higher metal immobilisation fraction. Furthermore, the acid addition promotes the formation of small Au-rich nanoparticles on said supports, increasing the final metal dispersion. These two effects result in significantly enhanced catalytic activity. This method is demonstrated for PAA-stabilized AuPd nanoparticles supported on two different carbons and is extended to a series of stabilisers and TiO2 as support. The second research chapter looks at new materials for the visible-light driven photoproduction of H2O2. Most research aim at developing strategies to increase the photocatalytic activity of TiO2-based systems under UV irradiation. While several strategies exist, the most effective one is the loading of metallic nanoparticles. This chapter aims at extending this approach to a visible-light sensitive semiconductor (graphitic carbon nitride, GCN). After screening different metals, the most active photocatalyst, AgNi/GCN, was selected and further optimized. The Ag-Ni synergy observed through the photoproduction of H2O2 was attributed to a better charge separation, a higher conductivity, and an enhanced selectivity towards the formation of H2O2.

Item Type:	Thesis (PhD)
Date Type:	Completion
Status:	Unpublished
Schools:	Chemistry
Date of First Compliant Deposit:	1 August 2023
Last Modified:	10 Feb 2024 02:31
URI:	https://orca.cardiff.ac.uk/id/eprint/161385

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