Simultaneous photocatalytic removal of nitrate and oxalic acid over Cu2O/TiO2 and Cu2O/TiO2-AC composites

Haruna Adamu, Alan J. McCue, Rebecca S.F. Taylor, Haresh G. Manyar, James A. Anderson*

*Corresponding author for this work

Research output: Contribution to journalArticle

34 Citations (Scopus)
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Abstract

Cu2O/TiO2 (1–10 wt% Cu2O) and 2.5% Cu2O/TiO2-AC (2.5–20 wt% AC) photocatalyst composites were synthesised by an ethanol reduction method. The materials were characterised by a number of techniques which confirmed the presence of Cu2O in contact with the TiO2. Pure TiO2 alone was not active for the simultaneous photocatalytic removal of nitrate and oxalic acid under conditions employed, however, photocatalytic activity was observed for TiO2 and TiO2/AC in the presence of Cu2O. This may have resulted from suppression of charge recombination via creation of a p-n heterojunction between Cu2O and TiO2. Within the series, 2.5% Cu2O/TiO2 exhibited the best photocatalytic performance with 57.6 and 99.8% removal of nitrate and oxalic acid, respectively, with selectivities of 45.7, 12.4 and 41.9% to NH4 +, NO2 and N2, respectively after 3 h. For the carbon containing photocatalysts, 2.5% Cu2O/TiO2-2·5AC displayed the highest activity with 42.5 and 96.6% removal of nitrate and oxalic acid, respectively, with 32.7, 11.6 and 55.7% selectivities to NH4 +, NO2 and N2, respectively. The highest AC loading tested resulted in selectivity to NH4 + of 21.6 with no NO2 detected, together with an improved N2 selectivity (78.4%) albeit at lower (12.7%) nitrate conversion. Data suggests that Cu2O/TiO2 can be used in the photocatalytic reduction of nitrate and improved selectivity towards N2 can be attained by influencing factors which control the relative rate of oxalic acid consumption.

Original languageEnglish
Pages (from-to)181-191
Number of pages11
JournalApplied Catalysis B: Environmental
Volume217
Early online date3 Jun 2017
DOIs
Publication statusPublished - 15 Nov 2017

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Keywords

  • Activated carbon
  • Composites
  • Nitrate
  • Oxalic acid
  • Photocatalysis
  • Titania

ASJC Scopus subject areas

  • Catalysis
  • Environmental Science(all)
  • Process Chemistry and Technology

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