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Enhancing Hematite Photoanode Activity for Water Oxidation by Incorporation of Reduced Graphene Oxide
Author(s) -
do Amaral Carminati Saulo,
Souza Flavio L.,
Nogueira Ana F.
Publication year - 2016
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.201500659
Subject(s) - hematite , graphene , oxide , chemical engineering , chemistry , materials science , inorganic chemistry , nanotechnology , mineralogy , metallurgy , engineering
Two effective methods to prepare reduced graphene oxide (rGO)/hematite nanostructured photoanodes and their photoelectrochemical characterization towards water splitting reactions are presented. First, graphene oxide (GO) is reduced to rGO using hydrazine in a basic solution containing tetrabutylammonium hydroxide (TBAOH), and then deposited over the nanostructured hematite photoanodes previously treated at 750 °C for 30 min. The second method follows the deposition of a paste containing a mixture of hematite nanoparticles and rGO sheets by the doctor‐blade method, varying the rGO concentration. Since hematite suffers from low electron mobility, a low absorption coefficient, high recombination rates and slow reaction kinetics, the incorporation of rGO in the hematite can overcome such limitations due to graphene's exceptional properties. Using the first method, the rGO incorporation results in a photocurrent density increase from 0.56 to 0.82 mA cm −2 at 1.23 V RHE . Our results indicate that the rGO incorporation in the hematite photoanodes shows a positive effect in the reduction of the electron–hole recombination rate.