Abstract
AbstractThe direct synthesis of H2O2 from molecular H2 and O2 over Pd-based catalysts, prepared via an industrially relevant, excess chloride co-impregnation procedure is investigated. Initial studies into the well-established PdAu system demonstrated the key role of Pd: Au ratio on catalytic activity, under conditions that have previously been found to be optimal for H2O2 formation. Further investigations using the optimal Pd: Au ratio identified the role of the catalyst support in controlling particle size and Pd oxidation state and thus catalytic performance. Subsequently, with an aim to replace Au with cheaper alternatives, the alloying of Pd with more abundant secondary metals is explored. Graphical Abstract
Highlights
The direct synthesis of hydrogen peroxide (H2O2), a powerful and environmentally benign oxidising agent, offers an attractive alternative to the current means of production on an industrial scale, the anthraquinone oxidation process
With the performance of PdAu catalysts towards the direct synthesis and subsequent degradation of H 2O2 well reported to be highly dependent on catalyst support [25] and a growing interest in the alloying of Pd with more abundant base metals [26,27,28,29,30,31,32,33,34] we investigate the wider applicability of the excess chloride co-impregnation methodology to catalyst preparation
Under reaction conditions which have previously been optimised for H2O2 production [35] and using TiO2 (P25) as the catalyst support, established the effect of Pd: Au ratio the catalytic activity of supported metal catalysts prepared via an excess-chloride methodology towards H 2O2 synthesis and its subsequent degradation (Fig. 1)
Summary
The direct synthesis of hydrogen peroxide (H2O2), a powerful and environmentally benign oxidising agent, offers an attractive alternative to the current means of production on an industrial scale, the anthraquinone oxidation process. Due to the low stability of H2O2, decomposing readily to H 2O at relatively mild temperatures or under an alkali pH, the use of acidic stabilizing agents is common [3] While such additives prolong the shelf life of H2O2 they can promote reactor corrosion, decrease catalyst lifetime and necessitate the use of additional purification steps to remove such impurities from product streams, with the associated costs passed on to the end user [4]. While numerous methods to synthesize supported PdAu catalysts for H2O2 generation have been investigated, wet co-impregnation is perhaps both the most popular and most facile [18, 19] This route to catalyst synthesis is typically somewhat hampered by poor dispersion of active metals, with a bimodal distribution of metal nanoparticles previously reported [8, 20, 21]. With the performance of PdAu catalysts towards the direct synthesis and subsequent degradation of H 2O2 well reported to be highly dependent on catalyst support [25] and a growing interest in the alloying of Pd with more abundant base metals [26,27,28,29,30,31,32,33,34] we investigate the wider applicability of the excess chloride co-impregnation methodology to catalyst preparation
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
