TY - JOUR
T1 - Controlled Growth of Ferrihydrite Branched Nanosheet Arrays and Their Transformation to Hematite Nanosheet Arrays for Photoelectrochemical Water Splitting
AU - Ji, Mei
AU - Cai, Jinguang
AU - Ma, Yurong
AU - Qi, Limin
N1 - Publisher Copyright:
© 2015 American Chemical Society.
PY - 2016/2/24
Y1 - 2016/2/24
N2 - The morphology engineering represents an alternative route toward efficient hematite photoanodes for photoelectrochemical (PEC) water splitting without changing the chemical composition. In this work, a facile and mild solvothermal synthesis of unique ferrihydrite branched nanosheet arrays vertically aligned on FTO substrate was achieved at around 100 °C. The hierarchical branched ferrihydrite nanosheet arrays consisted of tiny branches up to 40 nm in length grown almost vertically on stem nanosheets ∼10 nm in thickness. Moreover, the variation of the morphology of the ferrihydrite nanostructures from bare nanosheet arrays through branched nanosheet arrays to dense branched structures can be readily achieved through the regulation of the reaction time and temperature. The obtained ferrihydrite branched nanosheet arrays can be in situ transformed into α-Fe2O3 nanosheet arrays with small surface protrusions upon annealing at 550 °C. After a simple postgrowth Ti-doping process, the resulting Ti-doped α-Fe2O3 nanosheet arrays showed a good PEC performance for water splitting with a photocurrent density of 1.79 mA/cm2 at 1.6 V vs RHE under AM 1.5G illumination (100 mW/cm2). In contrast, the Ti-doped irregular aggregates of the α-Fe2O3 nanograins transformed from dense ferrihydrite branched structures exhibited a much lower photocurrent density (0.41 mA/cm2 at 1.6 V vs RHE), demonstrating the important influence of the morphology of α-Fe2O3 photoanodes on the PEC performance.
AB - The morphology engineering represents an alternative route toward efficient hematite photoanodes for photoelectrochemical (PEC) water splitting without changing the chemical composition. In this work, a facile and mild solvothermal synthesis of unique ferrihydrite branched nanosheet arrays vertically aligned on FTO substrate was achieved at around 100 °C. The hierarchical branched ferrihydrite nanosheet arrays consisted of tiny branches up to 40 nm in length grown almost vertically on stem nanosheets ∼10 nm in thickness. Moreover, the variation of the morphology of the ferrihydrite nanostructures from bare nanosheet arrays through branched nanosheet arrays to dense branched structures can be readily achieved through the regulation of the reaction time and temperature. The obtained ferrihydrite branched nanosheet arrays can be in situ transformed into α-Fe2O3 nanosheet arrays with small surface protrusions upon annealing at 550 °C. After a simple postgrowth Ti-doping process, the resulting Ti-doped α-Fe2O3 nanosheet arrays showed a good PEC performance for water splitting with a photocurrent density of 1.79 mA/cm2 at 1.6 V vs RHE under AM 1.5G illumination (100 mW/cm2). In contrast, the Ti-doped irregular aggregates of the α-Fe2O3 nanograins transformed from dense ferrihydrite branched structures exhibited a much lower photocurrent density (0.41 mA/cm2 at 1.6 V vs RHE), demonstrating the important influence of the morphology of α-Fe2O3 photoanodes on the PEC performance.
KW - ferrihydrite
KW - hematite
KW - morphology engineering
KW - nanosheet arrays
KW - photoelectrochemical water splitting
UR - http://www.scopus.com/inward/record.url?scp=84958958860&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84958958860&partnerID=8YFLogxK
U2 - 10.1021/acsami.5b08116
DO - 10.1021/acsami.5b08116
M3 - Article
AN - SCOPUS:84958958860
VL - 8
SP - 3651
EP - 3660
JO - ACS applied materials & interfaces
JF - ACS applied materials & interfaces
SN - 1944-8244
IS - 6
ER -