Determination of the structure-activity relationship of amorphous iron -doped cobalt tungstate for its catalytic application Adrian Sanz Arjona, Josef Kosler, Kirsten Marie Ørnsbjerg Jensen Centre for High Entropy Alloy Catalysis (CHEAC), Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 København Ø has shown an exciting potential for replacing the current benchmark materials such as IrO 2 and Pt/C-based catalysts 2 which are more expensive and not as abundant. More importantly, disordered materials have been proven to be a more active material for OER than the crystalline counterpart. 3 Although this behaviour has been well reported, the structural role is not clear. In addition, different degrees of iron doping is proposed to add an additional disorder enhancing the catalytic activity. This project aims to synthesise and characterise these materials to determine the relationship between their structure and catalytic properties linked to the presence of iron in the structure. This will help to fathom the structure-activity relationship of these materials in order to design the “most” suitable for a future application. A modification of the experimental co-precipitation technique reported by Wu et al . 2 was carried out to produce amorphous tungstate oxides. The techniques selected for characterization include powder X-ray diffraction (PXRD) and its pair distribution function (PDF), X-ray fluorescence (XRF), Raman and FTIR spectroscopy. “Big box” modelling of potential clusters is frequently approached for resolving these structures. Crystalline counterparts to the amorphous materials were synthesised by annealing for direct comparison of both materials with a different degree of crystallinity. Its correlation unveiled the structural divergences that lead to the enhanced activity of the distorted structure. Finally, the crystallisation process was discovered by in - situ hydrothermal and solid reaction synchrotron measurements. Finding low-cost catalysts with high performance for different applications (e.g. water splitting reaction), is critical towards solving the current global energy crisis. 1 In this context, amorphous iron doped CoWO 4 (a-Fe III x Co II 1-x WO 4 )
References 1. S. Anantharaj and S. Noda, Small , 2020, 16 , 1–24. 2. J. Wu, R. Xie, X. Hu, Z. Nie, Y. Shi, Y. Yu and N. Yang, J. Mater. Chem. A , 2021, 9 , 9753–9760. 3. Y. Duan, Z. Y. Yu, S. J. Hu, X. S. Zheng, C. T. Zhang, H. H. Ding, B. C. Hu, Q. Q. Fu, Z. L. Yu, X. Zheng, J. F. Zhu, M. R. Gao and S. H. Yu, Angewandte Chemie - International Edition , 2019, 58 , 15772–15777.
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