Simultaneous Formation of CO and H2O2from CO2and H2O with a Ag-MnOx/CaTiO3 Photocatalyst

Tayyebeh Soltani, Akira Yamamoto, Surya Pratap Singh, Akihiko Anzai, Eri Fudo, Atsuhiro Tanaka, Hiroshi Kominami, Hisao Yoshida

Research output: Contribution to journalArticlepeer-review

Abstract

Carbon monoxide (CO) is an important feedstock for the chemical industry, and hydrogen peroxide (H2O2) is also an important chemical with versatile applications. Here, a photocatalytic system was discovered for the simultaneous production of CO and H2O2from CO2and H2O with both high activity and selectivity without any externally applied voltage and any consumption of chemical compounds, which was promoted by using a calcium titanate (CaTiO3) photocatalyst modified with a silver-manganese oxide (Ag-MnOx) dual cocatalyst. Although a Ag/CaTiO3(CTO) photocatalyst was reported to reduce CO2with water to form CO and O2, the coexistence of MnOxspecies with silver nanoparticles (NPs) not only improved the CO formation rate more than 2 times with a selectivity of 76% but also changed the selectivity of the oxidative reaction and forms H2O2instead of O2with a high selectivity of 99%. The Ag NPs promoted the CO2reduction to CO by the photoexcited electrons, and the Mn(III) oxide species deposited on the CaTiO3surface contributed to the water oxidation to H2O2by the positive holes in the aid of HCO3-as a reaction mediator. The produced CO is easily separated from the aqueous solution to the gas phase, and the H2O2is stably stored in the aqueous HCO3-solution. This photocatalytic system can utilize the stable and ubiquitous molecules (CO2and H2O) to produce reactive and useful molecules (CO and H2O2), concurrently, meaning that it can convert photoenergy to storable chemical energy to increase sustainability.

Original languageEnglish
Pages (from-to)6500-6510
Number of pages11
JournalACS Applied Energy Materials
Volume4
Issue number7
DOIs
Publication statusPublished - Jul 26 2021
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Chemical Engineering (miscellaneous)
  • Energy Engineering and Power Technology
  • Electrochemistry
  • Electrical and Electronic Engineering
  • Materials Chemistry

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