Drawing the distinguished graphite carbon nitride (g-C 3 N 4 ) on SnO 2 nanoflake film for solar water oxidation Young Jun Seo a , Pran Krisna Das b , Maheswari Arunachalam c , Kwang-Soon Ahn d , Jun-Seok Ha e , Soon Hyung Kang a,* a Department of Chemistry Education, Chonnam National University, Yongbong-ro 77, Yongbong-dong, Gwangju 500-757, Republic of Korea b Department of Advanced Chemicals and Engineering, Chonnam National University, Yongbong-ro 77, Yongbong- dong, Gwangju 500-757, Republic of Korea c Department of Chemistry, Chonnam National University, Yongbong-ro 77, Yongbong-dong, Gwangju 500-757, Republic of Korea d School of Chemical Engineering, Yeungnam University, Gyeongsan 712-749, Republic of Korea e Department of Chemical Engineering, Chonnam National University, Gwangju 61186, Republic of Korea highlights Graphite carbon (g-C 3 N 4 ) was synthesized and deposited by electrophoretic deposition on SnO 2 nanoflake film. g-C 3 N 4 /SnO 2 nanoflake film exhibits the photocurrent density of 0.15 mA/cm 2 at 1.23 V RHE . article info Article history: Received 14 April 2020 Received in revised form 10 June 2020 Accepted 15 June 2020 Available online xxx Keywords: Photoelectrochemical water splitting SnO 2 nanoflake Graphite carbon (g-C 3 N 4 ) Heterojunction Electrophoretic deposition abstract Tin dioxide (SnO 2 ) nanoflakes electrodes were developed by a simple hydrothermal syn- thesis with a length of ~1.5 mm. Based on this electrode, g-C 3 N 4 layer with an energetic band gap of about 2.7 eV was deposited by electrophoretic deposition under constant po- tential (30 V) for 3, 5 and 10 min, respectively. To enhance the chemical adsorption of g- C 3 N 4 sheets on SnO 2 nanoflake film, the SnO 2 film was put in 0.5 M NaOH solution, and OH ions were coated via the entire surface area of SnO 2 film. As increasing the deposited time of the g-C 3 N 4 layer to 5 min, the g-C 3 N 4 nanosheets steadily covered the surface area. In particular, g-C 3 N 4 (5min)/SnO 2 nanoflake film exhibited the maximum photocurrent den- sity (J SC ), 0.15 mA/cm 2 at 1.23 V vs. Reversible Hydrogen Electrode under the full sun, and a slight photoresponse in the visible light of 400e450 nm contributes to the enhancement of J SC , compared to that of SnO 2 nanoflake film. Furthermore, the interfacial resistance after the coating of g-C 3 N 4 layer is sharply reduced, which is resulted from the electrocatalytic effect of g-C 3 N 4 layer. Thus, the heterojunction developed between the core SnO 2 layer showing a high conductivity and the shell g-C 3 N 4 layer as the visible light absorbing me- dium can improve the photoelectrochemical performance. © 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved. * Corresponding author. E-mail address: skang@jnu.ac.kr (S.H. Kang). Available online at www.sciencedirect.com ScienceDirect journal homepage: www.elsevier.com/locate/he international journal of hydrogen energy xxx (xxxx) xxx https://doi.org/10.1016/j.ijhydene.2020.06.143 0360-3199/© 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved. Please cite this article as: Seo YJ et al., Drawing the distinguished graphite carbon nitride (g-C 3 N 4 ) on SnO 2 nanoflake film for solar water oxidation, International Journal of Hydrogen Energy, https://doi.org/10.1016/j.ijhydene.2020.06.143