Molecularly rigid porous polyamine host enhances barium titanate catalysed H 2 O 2 generation †

Akalya Karunakaran, Chris R. Bowen, Steve Dunn, Thuy-Phuong T. Pham, Andrea Folli, Philip J. Fletcher, Mariolino Carta, Neil B. McKeown, Frank Marken

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Abstract

Barium titanate (BTO) is well-known (as a photo- or sono/piezo-catalyst) to produce hydrogen peroxide via 2-electron reduction of oxygen in the presence of a sacrificial quencher, such as isopropanol. While barium titanate nanoparticles with a tetragonal crystal structure (piezoelectric) are particularly reactive, the recovery and reuse of these nano-catalysts from reactions can be difficult. Here, barium titanate nanoparticles of typically 200 nm to 600 nm diameter are embedded into a host film of a polymer of intrinsic microporosity (PIM-EA-TB). Due to molecular rigidity of the polymer, there is no capping effect, and the surface catalytic reaction occurs effectively with a catalyst embedded in the polymer. In this exploratory work, the catalytic formation of H2O2 in the presence of isopropanol is investigated via kinetic studies and by electron paramagnetic resonance (EPR). Perhaps surprisingly, at a neutral pH the rate of the catalytic reaction is substantially increased when barium titanate is embedded into the polymer host and when the polymer is protonated. This is attributed here to a “kinetic cage effect” which exploits the tertiary amine in the polymer backbone with anodic and cathodic processes coupled into a pH neutral reaction.

Original languageEnglish
Pages (from-to)16261-16268
Number of pages8
JournalNew Journal of Chemistry
Volume48
Issue number37
DOIs
Publication statusPublished - 2 Sept 2024
Externally publishedYes

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