TY - JOUR
T1 - Exploring Graphene Quantum Dots/TiO2 interface in photoelectrochemical reactions
T2 - Solar to fuel conversion
AU - Sudhagar, Pitchaimuthu
AU - Herraiz-Cardona, Isaac
AU - Park, Hun
AU - Song, Taesup
AU - Noh, Seung Hyun
AU - Gimenez, Sixto
AU - Sero, Ivan Mora
AU - Fabregat-Santiago, Francisco
AU - Bisquert, Juan
AU - Terashima, Chiaki
AU - Paik, Ungyu
AU - Kang, Yong Soo
AU - Fujishima, Akira
AU - Han, Tae Hee
N1 - Funding Information:
This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF 2014R1A1A1008196 ). The author PS (ID: P13374) are highly grateful to the “ Japan Society for the Promotion of Science (JSPS) Postdoctoral Fellowship Program for Foreign Researchers ” for the financial assistance. This work was also supported by the Korea Center for Artificial Photosynthesis (KCAP) located in Sogang University funded through the National Research Foundation of Korea (No. 2009-0093883).
Publisher Copyright:
© 2015 Published by Elsevier Ltd.
PY - 2016/1/1
Y1 - 2016/1/1
N2 - Photocarrier (e-/h+) generation at low dimension graphene quantum dots offers multifunctional applications including bioimaging, optoelectronics and energy conversion devices. In this context, graphene quantum dots onto metal oxide electron transport layer finds great deal of attention in solar light driven photoelectrochemical (PEC) hydrogen fuel generation. The merits of combining tailored optical properties of the graphene quantum dots sensitizer with the transport properties of the host wide band gap one dimensional nanostructured semiconductor provide a platform for high charge collection which promotes catalytic proton reduction into fuel generation at PEC cells. However, understanding the underlying mechanism of photocarrier transfer characteristics at graphene quantum dots/metal oxide interface during operation is often difficult as graphene quantum dots may have a dual role as sensitizer and catalyst. Therefore, exploring photocarrier generation and injection at graphene quantum dot/metal oxide heterointerfaces in contact with hole scavenging electrolyte afford a new pathway in developing graphene quantum dots based photoelectrochemical fuel generation systems. In this work, we demonstrate direct assembly of surface modified graphene quantum dots (∼2 nm particle size) onto TiO2 hollow nanowire (∼3 μm in length and ∼100 to 250 nm in diameter) by electrostatic attraction and examine the photocarrier accumulation and recombination processes leading to device operation. Optical characterization reveals that GQDs absorbed light photons at visible light wavelength up to 600 nm. Hybrid TiO2-GQDs heterostructures show a photocurrent enhancement of ∼70% for water oxidation compared to pristine TiO2 using sacrificial-free electrolyte, which is further validated by incident photon to current efficiency. Additionally, the charge accumulation processes and charge transfer characteristics are investigated by electrochemical impedance spectroscopy. These results provide the platform to understand the insights of graphene quantum dots/metal oxide interfaces in PEC reactions and discuss the feasibility of graphene quantum dots in wide range of electrochemical and photoelectrochemical based fuel conversion devices.
AB - Photocarrier (e-/h+) generation at low dimension graphene quantum dots offers multifunctional applications including bioimaging, optoelectronics and energy conversion devices. In this context, graphene quantum dots onto metal oxide electron transport layer finds great deal of attention in solar light driven photoelectrochemical (PEC) hydrogen fuel generation. The merits of combining tailored optical properties of the graphene quantum dots sensitizer with the transport properties of the host wide band gap one dimensional nanostructured semiconductor provide a platform for high charge collection which promotes catalytic proton reduction into fuel generation at PEC cells. However, understanding the underlying mechanism of photocarrier transfer characteristics at graphene quantum dots/metal oxide interface during operation is often difficult as graphene quantum dots may have a dual role as sensitizer and catalyst. Therefore, exploring photocarrier generation and injection at graphene quantum dot/metal oxide heterointerfaces in contact with hole scavenging electrolyte afford a new pathway in developing graphene quantum dots based photoelectrochemical fuel generation systems. In this work, we demonstrate direct assembly of surface modified graphene quantum dots (∼2 nm particle size) onto TiO2 hollow nanowire (∼3 μm in length and ∼100 to 250 nm in diameter) by electrostatic attraction and examine the photocarrier accumulation and recombination processes leading to device operation. Optical characterization reveals that GQDs absorbed light photons at visible light wavelength up to 600 nm. Hybrid TiO2-GQDs heterostructures show a photocurrent enhancement of ∼70% for water oxidation compared to pristine TiO2 using sacrificial-free electrolyte, which is further validated by incident photon to current efficiency. Additionally, the charge accumulation processes and charge transfer characteristics are investigated by electrochemical impedance spectroscopy. These results provide the platform to understand the insights of graphene quantum dots/metal oxide interfaces in PEC reactions and discuss the feasibility of graphene quantum dots in wide range of electrochemical and photoelectrochemical based fuel conversion devices.
KW - charge transfer
KW - graphene quantum dots
KW - photoelectrochemical
KW - solar fuel
KW - TiO
KW - water splitting
UR - http://www.scopus.com/inward/record.url?scp=84947997741&partnerID=8YFLogxK
U2 - 10.1016/j.electacta.2015.11.048
DO - 10.1016/j.electacta.2015.11.048
M3 - Article
AN - SCOPUS:84947997741
SN - 0013-4686
VL - 187
SP - 249
EP - 255
JO - Electrochimica Acta
JF - Electrochimica Acta
ER -
