Titania Hybrid Carbon Spherogels for Photocatalytic Hydrogen Evolution

Jorge Alberto Torres Rodriguez, Stephen Maykala, Miralem Salihovic, Maurizio Ermanno Musso, Nicola Hüsing, Dominik Eder, Volker Presser, Alexey Cherevan, Michael Elsässer*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Recently, carbon spherogels have been introduced as a novel monolithic aerogel composed of hollow spheres. This material is conveniently obtained via polystyrene (PS) sphere templating. In the present study, we apply a water-soluble titania precursor (titanium(IV) bis(ammonium lactate) to the aqueous sol-gel synthesis based on resorcinol-formaldehyde (RF) to effectively encapsulate titania. In this way, a very high mass loading of up to 59 mass% of titania can be confined strictly to the inside of the hollow carbon spheres. In the final synthesis step, carbonization at 800 °C has three simultaneous effects: Transformation of the RF coating on PS into microporous carbon, PS template removal by decomposition, and formation of titania due to precursor dissociation. A deliberate tuning of the microporous carbon shell, accessibility of the titania, titania amount, and titania's polymorph is further demonstrated by thermal treatment under a carbon dioxide atmosphere. In contrast to non-tuned or TiC-containing carbon spherogels, CO 2 activation of the composites results in a three orders of magnitude rise of their photocatalytic activity towards hydrogen evolution reaction, which we evaluate using flow and batch reactors. We further show that this effect is related to the partial etching of the carbon shell, which renders the TiO 2 surface accessible to the reactants in the solution and allows for an efficient hole scavenging. Given the simplicity of the hybrid carbon spherogel (HCS) composite fabrication, the high degree of control of their morphological characteristics, and the striking effects of CO 2-activation on performance, we believe that our results will contribute to the development of similar carbon-inorganic composites.

Original languageEnglish
Article numberVolume 202, Part 1
Pages (from-to)487-494
Number of pages8
JournalCarbon
Volume202
Issue numberVolume 202, Part 1
DOIs
Publication statusPublished - 15 Jan 2023

Bibliographical note

Publisher Copyright:
© 2022 Elsevier Ltd

Keywords

  • Hybrid aerogels
  • Nanoporous materials
  • Hollow carbon spheres
  • Photocatalysis
  • Hydrogen evolution reaction
  • Titania

Fields of Science and Technology Classification 2012

  • 104 Chemistry

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