Structure and Activity of Photochemically Deposited “CoPi” Oxygen Evolving Catalyst on Titania

View Author Information
Department of Chemistry and Center for Photochemical Sciences, Bowling Green State University, Bowling Green, Ohio 43403, United States
Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, United States
§ Department of Chemistry, Northwestern University, Evanston, Illinois 60208-3113, United States
*E-mail: [email protected] (F.N.C.), [email protected] (L.X.C.).
Cite this: ACS Catal. 2012, 2, 10, 2150–2160
Publication Date (Web):September 10, 2012
Copyright © 2012 American Chemical Society
Article Views
Read OnlinePDF (2 MB)
Supporting Info (1)»


The cobalt phosphate “CoPi” oxygen evolving catalyst (OEC) was photochemically grown on the surface of TiO2 photoanodes short-circuited to a Pt wire under bandgap illumination in the presence of Co(NO3)2 and sodium phosphate (NaPi) buffer. Extended photodeposition (15 h) using a hand-held UV lamp readily permitted quantitative structural and electrochemical characterization of the photochemically deposited CoPi OEC on titania. The formed catalytic material was characterized by scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) spectroscopy experiments, illustrating the production of easily visualized micrometer scale clusters throughout the titania surface containing both cobalt and phosphate. X-ray absorption fine structure (XAFS) and X-ray absorption near edge structure (XANES) studies indicated that the newly formed material was structurally consistent with the production of molecular cobaltate clusters composed of a cobalt oxide core that is most likely terminated by phosphate ions. The oxidation state, structure, and the oxygen evolution activity of this CoPi catalyst photochemically grown on titania were quantitatively similar to the analogous electrodeposited materials on titania as well as those produced on other electroactive substrates. From pH-dependent electrochemical measurements, proton-coupled electron transfer was shown to be an important step in the oxygen evolution mechanism from the photodeposited OEC clusters on TiO2 in agreement with previous reports on other materials. Similarly, the utilization of NaClO4 as electrolyte during the controlled potential electrolysis experiments failed to maintain an appreciable current density, indicating that the catalyst was rendered inactive with respect to the one immersed in NaPi. The requirement of having phosphate present for long-term catalytic activity implied that the same “repair” mechanism might be invoked for the hybrid materials investigated here. The OEC catalyst operated at Faradaic efficiencies close to 100% in controlled potential electrolysis experiments, indicating that the holes relayed to the photodeposited CoPi are indeed selective for promoting water oxidation on titania.

Supporting Information

Jump To

Photographs of TiO2 and TiO2/CoPi films, EDX mapping of cobalt and phosphate on TiO2 after 15-h CoPi photodeposition, XAFS and EDX evidence of Co(II) and phosphate adsorption on TiO2, and SEM/EDX of CoPi electrodeposited on the mesoscopic TiO2 substrate. This material is available free of charge via the Internet at

Terms & Conditions

Most electronic Supporting Information files are available without a subscription to ACS Web Editions. Such files may be downloaded by article for research use (if there is a public use license linked to the relevant article, that license may permit other uses). Permission may be obtained from ACS for other uses through requests via the RightsLink permission system:

Cited By

This article is cited by 50 publications.

  1. Zehui Yu, Qikang Huang, Xingxing Jiang, Xiaowei Lv, Xin Xiao, Mingkui Wang, Yan Shen, Gunther Wittstock. Effect of a Cocatalyst on a Photoanode in Water Splitting: A Study of Scanning Electrochemical Microscopy. Analytical Chemistry 2021, 93 (36) , 12221-12229.
  2. Preeti Dagar, Nandan Ghorai, Kasinath Ojha, Hirendra N. Ghosh, Ashok K. Ganguli. CdS–CNT–CoPi Heterostructures for Simultaneous Exciton Separation: Ultrafast and Photoelectrochemical Studies. The Journal of Physical Chemistry C 2021, 125 (16) , 8684-8695.
  3. D. Amaranatha Reddy, Yujin Kim, Hyung Seop Shim, K. Arun Joshi Reddy, Madhusudana Gopannagari, D. Praveen Kumar, Jae Kyu Song, Tae Kyu Kim. Significant Improvements on [email protected] Photoanode Solar Water Splitting Performance by Extending Visible-Light Harvesting Capacity and Charge Carrier Transportation. ACS Applied Energy Materials 2020, 3 (5) , 4474-4483.
  4. Min Chen, Yiming Xu. Trace Amount CoFe2O4 Anchored on a TiO2 Photocatalyst Efficiently Catalyzing O2 Reduction and Phenol Oxidation. Langmuir 2019, 35 (29) , 9334-9342.
  5. Mahdi Hesari, Xianwen Mao, Peng Chen. Charge Carrier Activity on Single-Particle Photo(electro)catalysts: Toward Function in Solar Energy Conversion. Journal of the American Chemical Society 2018, 140 (22) , 6729-6740.
  6. Mariana C. O. Monteiro, Gihoon Cha, Patrik Schmuki, and Manuela S. Killian . Metal–Phosphate Bilayers for Anatase Surface Modification. ACS Applied Materials & Interfaces 2018, 10 (7) , 6661-6672.
  7. Xiao Zhang, Xianqiang Xiong, Lianghui Wan, and Yiming Xu . Effect of a Co-Based Oxygen-Evolving Catalyst on TiO2-Photocatalyzed Organic Oxidation. Langmuir 2017, 33 (33) , 8165-8173.
  8. Fabrizio Sordello, Manuel Ghibaudo, and Claudio Minero . Photoelectrochemical Performance of the Ag(III)-Based Oxygen-Evolving Catalyst. ACS Applied Materials & Interfaces 2017, 9 (28) , 23800-23809.
  9. Jumpei Kamimura, Peter Bogdanoff, Fatwa F. Abdi, Jonas Lähnemann, Roel van de Krol, Henning Riechert, and Lutz Geelhaar . Photoelectrochemical Properties of GaN Photoanodes with Cobalt Phosphate Catalyst for Solar Water Splitting in Neutral Electrolyte. The Journal of Physical Chemistry C 2017, 121 (23) , 12540-12545.
  10. Xiaobo Li, Edwin B. Clatworthy, Stuart Bartlett, Anthony F. Masters, and Thomas Maschmeyer . Structural Investigation of Cobalt Oxide Clusters Derived from Molecular Cobalt Cubane, Trimer, and Dimer Oligomers in a Phosphate Electrolyte. The Journal of Physical Chemistry C 2017, 121 (21) , 11021-11026.
  11. Kasper Wenderich and Guido Mul . Methods, Mechanism, and Applications of Photodeposition in Photocatalysis: A Review. Chemical Reviews 2016, 116 (23) , 14587-14619.
  12. Donghyeon Kang, Tae Woo Kim, Stephen R. Kubota, Allison C. Cardiel, Hyun Gil Cha, and Kyoung-Shin Choi . Electrochemical Synthesis of Photoelectrodes and Catalysts for Use in Solar Water Splitting. Chemical Reviews 2015, 115 (23) , 12839-12887.
  13. Linlin Hao, Xianqiang Xiong, and Yiming Xu . Borate-Mediated Hole Transfer from Irradiated Anatase TiO2 to Phenol in Aqueous Solution. The Journal of Physical Chemistry C 2015, 119 (37) , 21376-21385.
  14. Ke Sun, Shaohua Shen, Yongqi Liang, Paul E. Burrows, Samuel S. Mao, and Deli Wang . Enabling Silicon for Solar-Fuel Production. Chemical Reviews 2014, 114 (17) , 8662-8719.
  15. Simona Ostachavičiūtė, Agnė Šulčiūtė, Eugenijus Valatka. The morphology and electrochemical properties of WO3 and Se-WO3 films modified with cobalt-based oxygen evolution catalyst. Materials Science and Engineering: B 2020, 260 , 114630.
  16. Yaru Wang, Jianjun Zhao, Chen Chen, Yiming Xu. Different performances of Ni 3 (PO 4 ) 2 in TiO 2 photocatalysis under aerobic and anaerobic conditions. Catalysis Science & Technology 2020, 10 (6) , 1761-1768.
  17. Chiheng Chu, Qianhong Zhu, Zhenhua Pan, Srishti Gupta, Dahong Huang, Yonghua Du, Seunghyun Weon, Yueshen Wu, Christopher Muhich, Eli Stavitski, Kazunari Domen, Jae-Hong Kim. Spatially separating redox centers on 2D carbon nitride with cobalt single atom for photocatalytic H 2 O 2 production. Proceedings of the National Academy of Sciences 2020, 117 (12) , 6376-6382.
  18. Zhenxing Li, Xiaofei Xing, Jianzheng Zhang, Mingming Li, Qiuyu Zhang. Highly ordered hierarchically macroporous- mesoporous TiO2 for thiol-ene polymer design by photoclick chemistry. Microporous and Mesoporous Materials 2020, 291 , 109696.
  19. Guozhen Fang, Zhifeng Liu, Changcun Han, Qijun Cai, Chonghao Ma, Zhengfu Tong. ZnO/In2S3/Co–Pi ternary composite photoanodes for enhanced photoelectrochemical properties. Journal of Materials Science: Materials in Electronics 2019, 30 (20) , 18943-18949.
  20. Vito Cristino, Luisa Pasti, Nicola Marchetti, Serena Berardi, Carlo Alberto Bignozzi, Alessandra Molinari, Francesco Passabi, Stefano Caramori, Lucia Amidani, Michele Orlandi, Nicola Bazzanella, Alberto Piccioni, Jagadesh Kopula Kesavan, Federico Boscherini, Luca Pasquini. Photoelectrocatalytic degradation of emerging contaminants at WO 3 /BiVO 4 photoanodes in aqueous solution. Photochemical & Photobiological Sciences 2019, 18 (9) , 2150-2163.
  21. Jingjing Xie, Hang Ping, Tiening Tan, Liwen Lei, Hao Xie, Xiao-Yu Yang, Zhengyi Fu. Bioprocess-inspired fabrication of materials with new structures and functions. Progress in Materials Science 2019, 105 , 100571.
  22. Junqi Li, Zheng Liang, Qianqian Song, Xiaotao Xu. NiFeOx nanosheets tight-coupled with Bi2WO6 nanosheets to improve the electrocatalyst for oxygen evolution reaction. Applied Surface Science 2019, 478 , 969-980.
  23. V. Di Palma, G. Zafeiropoulos, T. Goldsweer, W.M.M. Kessels, M.C.M. van de Sanden, M. Creatore, M.N. Tsampas. Atomic layer deposition of cobalt phosphate thin films for the oxygen evolution reaction. Electrochemistry Communications 2019, 98 , 73-77.
  24. Tianyu Liu, Martina Morelli, Yat Li. Hematite Materials for Solar-Driven Photoelectrochemical Cells. 2018,,, 159-218.
  25. Huayang Zhang, Wenjie Tian, Yunguo Li, Hongqi Sun, Moses O. Tadé, Shaobin Wang. A comparative study of metal (Ni, Co, or Mn)-borate catalysts and their photodeposition on rGO/ZnO nanoarrays for photoelectrochemical water splitting. Journal of Materials Chemistry A 2018, 6 (47) , 24149-24156.
  26. Peng Zhang, Takashi Tachikawa, Mamoru Fujitsuka, Tetsuro Majima. The Development of Functional Mesocrystals for Energy Harvesting, Storage, and Conversion. Chemistry - A European Journal 2018, 24 (24) , 6295-6307.
  27. Dong Ryeol Whang, Dogukan Hazar Apaydin. Artificial Photosynthesis: Learning from Nature. ChemPhotoChem 2018, 2 (3) , 148-160.
  28. Isolda Roger, Michael A. Shipman, Mark D. Symes. Earth-abundant catalysts for electrochemical and photoelectrochemical water splitting. Nature Reviews Chemistry 2017, 1 (1)
  29. Siman Fang, Songsong Li, Lei Ge, Changcun Han, Ping Qiu, Yangqin Gao. Synthesis of novel CoO x decorated CeO 2 hollow structures with an enhanced photocatalytic water oxidation performance under visible light irradiation. Dalton Transactions 2017, 46 (32) , 10578-10585.
  30. Alaka Samal, Smrutirekha Swain, Biswarup Satpati, Dipti Prakasini Das, Barada Kanta Mishra. 3 D Co 3 (PO 4 ) 2 -Reduced Graphene Oxide Flowers for Photocatalytic Water Splitting: A Type II Staggered Heterojunction System. ChemSusChem 2016, 9 (22) , 3150-3160.
  31. Koshal Kishor, Sulay Saha, Sri Sivakumar, Raj Ganesh S. Pala. Enhanced Water Oxidation Activity of the Cobalt(II,III) Oxide Electrocatalyst on an Earth-Abundant-Metal-Interlayered Hybrid Porous Carbon Support. ChemElectroChem 2016, 3 (11) , 1899-1907.
  32. Peng Zhang, Mamoru Fujitsuka, Tetsuro Majima. Development of tailored TiO 2 mesocrystals for solar driven photocatalysis. Journal of Energy Chemistry 2016, 25 (6) , 917-926.
  33. Xueqing Zhang, Anja Bieberle-Hütter. Modeling and Simulations in Photoelectrochemical Water Oxidation: From Single Level to Multiscale Modeling. ChemSusChem 2016, 9 (11) , 1223-1242.
  34. Masaaki Yoshida, Takehiro Mineo, Yosuke Mitsutomi, Futaba Yamamoto, Hirokatsu Kurosu, Satoru Takakusagi, Kiyotaka Asakura, Hiroshi Kondoh. Structural Relationship between CoO 6 Cluster and Phosphate Species in a Cobalt–Phosphate Water Oxidation Catalyst Investigated by Co and P K-edge XAFS. Chemistry Letters 2016, 45 (3) , 277-279.
  35. Pengzuo Chen, Kun Xu, Tianpei Zhou, Yun Tong, Junchi Wu, Han Cheng, Xiuli Lu, Hui Ding, Changzheng Wu, Yi Xie. Strong-Coupled Cobalt Borate Nanosheets/Graphene Hybrid as Electrocatalyst for Water Oxidation Under Both Alkaline and Neutral Conditions. Angewandte Chemie 2016, 128 (7) , 2534-2538.
  36. Pengzuo Chen, Kun Xu, Tianpei Zhou, Yun Tong, Junchi Wu, Han Cheng, Xiuli Lu, Hui Ding, Changzheng Wu, Yi Xie. Strong-Coupled Cobalt Borate Nanosheets/Graphene Hybrid as Electrocatalyst for Water Oxidation Under Both Alkaline and Neutral Conditions. Angewandte Chemie International Edition 2016, 55 (7) , 2488-2492.
  37. Justin B. Sambur, Tai-Yen Chen, Eric Choudhary, Guanqun Chen, Erin J. Nissen, Elayne M. Thomas, Ningmu Zou, Peng Chen. Sub-particle reaction and photocurrent mapping to optimize catalyst-modified photoanodes. Nature 2016, 530 (7588) , 77-80.
  38. Isolda Roger, Mark D. Symes. First row transition metal catalysts for solar-driven water oxidation produced by electrodeposition. Journal of Materials Chemistry A 2016, 4 (18) , 6724-6741.
  39. Hirokatsu KUROSU, Masaaki YOSHIDA, Yosuke MITSUTOMI, Sho ONISHI, Hitoshi ABE, Hiroshi KONDOH. In Situ Observations of Oxygen Evolution Cocatalysts on Photoelectrodes by X-ray Absorption Spectroscopy: Comparison between Cobalt-Phosphate and Cobalt-Borate. Electrochemistry 2016, 84 (10) , 779-783.
  40. Zeming Wu, Xi Tong, Pengtao Sheng, Weili Li, Xuehua Yin, Jianmei Zou, Qingyun Cai. Fabrication of high-performance CuInSe2 nanocrystals-modified TiO2 NTs for photocatalytic degradation applications. Applied Surface Science 2015, 351 , 309-315.
  41. Hui Shi, Johannes A. Lercher, Xiao-Ying Yu. Sailing into uncharted waters: recent advances in the in situ monitoring of catalytic processes in aqueous environments. Catalysis Science & Technology 2015, 5 (6) , 3035-3060.
  42. Bartłomiej M. Szyja, Rutger A. van Santen. Synergy between TiO 2 and Co x O y sites in electrocatalytic water decomposition. Physical Chemistry Chemical Physics 2015, 17 (19) , 12486-12491.
  43. Ahamed Irshad, N. Munichandraiah. Photochemical Deposition of Co-Ac Catalyst on ZnO Nanorods for Solar Water Oxidation. Journal of The Electrochemical Society 2015, 162 (4) , H235-H243.
  44. Katharina Klingan, Franziska Ringleb, Ivelina Zaharieva, Jonathan Heidkamp, Petko Chernev, Diego Gonzalez-Flores, Marcel Risch, Anna Fischer, Holger Dau. Water Oxidation by Amorphous Cobalt-Based Oxides: Volume Activity and Proton Transfer to Electrolyte Bases. ChemSusChem 2014, 7 (5) , 1301-1310.
  45. Marcel Risch, Katharina Klingan, Ivelina Zaharieva, Holger Dau. Water Oxidation by Co-Based Oxides with Molecular Properties. 2014,,, 163-185.
  46. Ali Han, Pingwu Du. Facile deposition of cobalt oxide based electrocatalyst on low-cost and tin-free electrode for water splitting. Journal of Energy Chemistry 2014, 23 (2) , 179-184.
  47. Ahamed Irshad, Nookala Munichandraiah. An oxygen evolution Co–Ac catalyst – the synergistic effect of phosphate ions. Phys. Chem. Chem. Phys. 2014, 16 (11) , 5412-5422.
  48. Takashi Tachikawa, Peng Zhang, Zhenfeng Bian, Tetsuro Majima. Efficient charge separation and photooxidation on cobalt phosphate-loaded TiO 2 mesocrystal superstructures. J. Mater. Chem. A 2014, 2 (10) , 3381-3388.
  49. Gun-hee Moon, Wooyul Kim, Alok D. Bokare, Nark-eon Sung, Wonyong Choi. Solar production of H 2 O 2 on reduced graphene oxide–TiO 2 hybrid photocatalysts consisting of earth-abundant elements only. Energy Environ. Sci. 2014, 7 (12) , 4023-4028.
  50. Lok-kun Tsui, Giovanni Zangari. Titania Nanotubes by Electrochemical Anodization for Solar Energy Conversion. Journal of The Electrochemical Society 2014, 161 (7) , D3066-D3077.