Photo-induced CO 2 reduction by CH 4 /H 2 O to fuels over Cu-modified g-C 3 N 4 nanorods under simulated solar energy

Beenish Tahir, Muhammad Tahir, Nor Aishah Saidina Amin

Research output: Contribution to journalArticlepeer-review

140 Citations (Scopus)

Abstract

Copper modified polymeric graphitic carbon nitride (Cu/g-C 3 N 4 ) nanorods for photo-induced CO 2 conversion with methane (CH 4 ) and water (H 2 O) as reducing system under simulated solar energy has been investigated. The nanocatalysts, synthesized by pyrolysis and sonication, were characterized by XRD, FTIR, Raman analysis, XPS, SEM, N 2 adsorption-desorption and PL spectroscopy. The presence of Cu 2+ ions over the g-C 3 N 4 structure inhibited charge carriers recombination process. The results indicated that photo-activity and selectivity of Cu/g-C 3 N 4 photo-catalyst for CO 2 reduction greatly dependent on the type of CO 2 -reduction system. CO 2 was efficiently converted to CH 4 and CH 3 OH with traces of C 2 H 4 and C 2 H 6 hydrocarbons in the CO 2 -water system. The yield of the main product, CH 4 over 3 wt.% Cu/g-C 3 N 4 was 109 μmole g-cata. −1  h −1 under visible light irradiation, significantly higher than the pure g-C 3 N 4 catalyst (60 μmole/g.cat). In photo-induced CO 2 -CH 4 reaction, CO and H 2 were detected as the main products with smaller amount of hydrocarbons. The highest efficiency was detected over 3 wt.%Cu-loading of g-C 3 N 4 and at optimal CH 4 /CO 2 feed ratio of 1.0. The maximum yield of CO and H 2 detected were 142 and 76 μmole g-catal. −1  h −1 , respectively at selectivity 66.6% and 32.5%, respectively. Significantly enhanced CO 2 /CH 4 reduction over Cu/g-C 3 N 4 was attributed to its polymeric structure with efficient charge transfer property and inhibited charges recombination rate. A proposed photo-induced reaction mechanism, corroborated with the experimental data, was also deliberated.

Original languageEnglish
Pages (from-to)875-885
Number of pages11
JournalApplied Surface Science
Volume419
DOIs
Publication statusPublished - Oct 15 2017
Externally publishedYes

Keywords

  • H O/CH reductants
  • Photocatalytic CO reforming
  • Polymeric graphitic carbon nitride
  • Solar energy

ASJC Scopus subject areas

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

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