Selective photocatalytic reduction of CO 2 by H 2 O/H 2 to CH 4 and CH 3 OH over Cu-promoted In 2 O 3 /TiO 2 nanocatalyst

Muhammad Tahir, Beenish Tahir, Nor Aishah Saidina Amin, Hajar Alias

Research output: Contribution to journalArticlepeer-review

128 Citations (Scopus)


Photocatalytic CO 2 reduction by H 2 O and/or H 2 reductant to selective fuels over Cu-promoted In 2 O 3 /TiO 2 photocatalyst has been investigated. The samples, prepared via a simple and direct sol-gel method, were characterized by XRD, SEM, TEM, XPS, N 2 adsorption-desorption, UV–vis diffuse reflectance, Raman and PL spectroscopy. Cu and In loaded into TiO 2 , oxidized as Cu 2+ and In 3+ , promoted efficient separation of photo-generated electron/hole pairs (e /h + ). The results indicate that the reduction rate of CO 2 by H 2 O to CH 4 approached to 181 μmol g −1 h −1 using 0.5% Cu-3% In 2 O 3 /TiO 2 catalyst, a 1.53 fold higher than the production rate over the 3% In 2 O 3 /TiO 2 and 5 times the amount produced over the pure TiO 2 . In addition, Cu was found to promote efficient production of CH 3 OH and yield rate reached to 68 μmol g −1 h −1 over 1% Cu-3% In 2 O 3 /TiO 2 catalyst. This improvement was attributed to charge transfer property and suppressed recombination rate by Cu-metal. More importantly, H 2 reductant was less favorable for CH 4 production, yet a significant amount of CH 4 and CH 3 OH were obtained using a mixture of H 2 O/H 2 reductant. Therefore, Cu-loaded In 2 O 3 /TiO 2 catalyst has shown to be capable for methanol production, whereas product selectivity was greatly depending on the amount of Cu-loading and the type of reductant. A photocatalytic reaction mechanism was proposed to understand the experimental results over the Cu-loaded In 2 O 3 /TiO 2 catalyst.

Original languageEnglish
Pages (from-to)46-55
Number of pages10
JournalApplied Surface Science
Publication statusPublished - Dec 15 2016
Externally publishedYes


  • CO photoreduction
  • Cu/In doped TiO
  • H O/H reductant
  • Methane
  • Methanol

ASJC Scopus subject areas

  • General Chemistry
  • Condensed Matter Physics
  • General Physics and Astronomy
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films


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