Understanding the Role of (W, Mo, Sb) Dopants in the Catalyst Evolution and Activity Enhancement of Co3 O4 during Water Electrolysis via In Situ Spectroelectrochemical Techniques

Thanh Tran-Phu; Manjunath Chatti; Joshua Leverett; Thi Kim Anh Nguyen; Darcy Simondson; Dijon A Hoogeveen; Alexander Kiy; The Duong; Bernt Johannessen; Jaydon Meilak; Patrick Kluth; Rose Amal; Alexandr N Simonov; Rosalie K Hocking; Rahman Daiyan; Antonio Tricoli

doi:10.1002/smll.202208074

Understanding the Role of (W, Mo, Sb) Dopants in the Catalyst Evolution and Activity Enhancement of Co₃ O₄ during Water Electrolysis via In Situ Spectroelectrochemical Techniques

Small. 2023 Jun;19(25):e2208074. doi: 10.1002/smll.202208074. Epub 2023 Mar 18.

Authors

Thanh Tran-Phu^{1

2}, Manjunath Chatti³, Joshua Leverett⁴, Thi Kim Anh Nguyen^{1

2}, Darcy Simondson³, Dijon A Hoogeveen³, Alexander Kiy⁵, The Duong⁶, Bernt Johannessen⁷, Jaydon Meilak⁸, Patrick Kluth⁵, Rose Amal⁴, Alexandr N Simonov³, Rosalie K Hocking⁸, Rahman Daiyan⁴, Antonio Tricoli^{1

2}

Affiliations

¹ Nanotechnology Research Laboratory, Research School of Chemistry, The Australian National University, Canberra, ACT, 2601, Australia.
² Nanotechnology Research Laboratory, Faculty of Engineering, University of Sydney, Sydney, NSW, 2006, Australia.
³ School of Chemistry, Monash University, Monash, Victoria, 3800, Australia.
⁴ Particles and Catalysis Research Laboratory, School of Chemical Engineering, The University of New South Wales, Sydney, NSW, 2052, Australia.
⁵ Department of Materials Physics, Research School of Physics, The Australian National University, Canberra, ACT, 2601, Australia.
⁶ School of Engineering, The Australian National University, Canberra, ACT, 2601, Australia.
⁷ Australian Synchrotron, Clayton, Victoria, 3168, Australia.
⁸ Department of Chemistry and Biotechnology, Swinburne University, Hawthorn, Victoria, 3166, Australia.

PMID: 36932896
DOI: 10.1002/smll.202208074

Abstract

Unlocking the potential of the hydrogen economy is dependent on achieving green hydrogen (H₂ ) production at competitive costs. Engineering highly active and durable catalysts for both oxygen and hydrogen evolution reactions (OER and HER) from earth-abundant elements is key to decreasing costs of electrolysis, a carbon-free route for H₂ production. Here, a scalable strategy to prepare doped cobalt oxide (Co₃ O₄ ) electrocatalysts with ultralow loading, disclosing the role of tungsten (W), molybdenum (Mo), and antimony (Sb) dopants in enhancing OER/HER activity in alkaline conditions, is reported. In situ Raman and X-ray absorption spectroscopies, and electrochemical measurements demonstrate that the dopants do not alter the reaction mechanisms but increase the bulk conductivity and density of redox active sites. As a result, the W-doped Co₃ O₄ electrode requires ≈390 and ≈560 mV overpotentials to reach ±10 and ±100 mA cm^-2 for OER and HER, respectively, over long-term electrolysis. Furthermore, optimal Mo-doping leads to the highest OER and HER activities of 8524 and 634 A g^-1 at overpotentials of 0.67 and 0.45 V, respectively. These novel insights provide directions for the effective engineering of Co₃ O₄ as a low-cost material for green hydrogen electrocatalysis at large scales.

Keywords: bifunctional water electrolysis; in situ Raman; in situ X-ray absorption spectroscopy (XAS); spinel cobalt oxides; water electrolyzers.

Abstract

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