TY - JOUR
T1 - Different Roles of Fe1- xNixOOH Cocatalyst on Hematite (α-Fe2O3) Photoanodes with Different Dopants
AU - Tsyganok, Anton
AU - Klotz, Dino
AU - Malviya, Kirtiman Deo
AU - Rothschild, Avner
AU - Grave, Daniel A.
N1 - Funding Information:
The research leading to these results has received funding from the European Research Council under the European Union’s Seventh Framework programme (FP/200702013)/ERC (Grant Agreement No. 617516). D.A.G. acknowledges support by Marie-Sklodowska-Curie Individual Fellowship No. 659491. K.D.M. acknowledges support in part at the Technion by a fellowship from the Lady Davis Foundation.
Publisher Copyright:
© 2018 American Chemical Society.
PY - 2018/4/6
Y1 - 2018/4/6
N2 - Transparent Fe1-xNixOOH overlayers (∼2 nm thick) were deposited photoelectrochemically on (001) oriented heteroepitaxial Sn- and Zn-doped hematite (α-Fe2O3) thin film photoanodes. In both cases, the water photo-oxidation performance was improved by the cocatalyst overlayers. Intensity modulated photocurrent spectroscopy (IMPS) was applied to study the changes in the hole current and recombination current induced by the overlayers. For the Sn-doped hematite photoanode, the improvement in performance after deposition of the Fe1-xNixOOH overlayer was entirely due to reduction in the recombination current, leading to a cathodic shift in the onset potential. For the Zn-doped hematite photoanode, in addition to a reduction in recombination current, an increase in the hole current to the surface was also observed after the overlayer deposition, leading to a cathodic shift in the onset potential as well as an enhancement in the plateau photocurrent. These results demonstrate that Fe1-xNixOOH cocatalysts can play different roles depending on the underlying hematite photoanode. The effect of the cocatalyst is not always limited to changes in the surface properties but may also cause an increase in hole current from the bulk to the surface that indicates a possible cross-link between surface and bulk processes.
AB - Transparent Fe1-xNixOOH overlayers (∼2 nm thick) were deposited photoelectrochemically on (001) oriented heteroepitaxial Sn- and Zn-doped hematite (α-Fe2O3) thin film photoanodes. In both cases, the water photo-oxidation performance was improved by the cocatalyst overlayers. Intensity modulated photocurrent spectroscopy (IMPS) was applied to study the changes in the hole current and recombination current induced by the overlayers. For the Sn-doped hematite photoanode, the improvement in performance after deposition of the Fe1-xNixOOH overlayer was entirely due to reduction in the recombination current, leading to a cathodic shift in the onset potential. For the Zn-doped hematite photoanode, in addition to a reduction in recombination current, an increase in the hole current to the surface was also observed after the overlayer deposition, leading to a cathodic shift in the onset potential as well as an enhancement in the plateau photocurrent. These results demonstrate that Fe1-xNixOOH cocatalysts can play different roles depending on the underlying hematite photoanode. The effect of the cocatalyst is not always limited to changes in the surface properties but may also cause an increase in hole current from the bulk to the surface that indicates a possible cross-link between surface and bulk processes.
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U2 - 10.1021/acscatal.7b04386
DO - 10.1021/acscatal.7b04386
M3 - Article
AN - SCOPUS:85045096135
SN - 2155-5435
VL - 8
SP - 2754
EP - 2759
JO - ACS Catalysis
JF - ACS Catalysis
IS - 4
ER -