2020 Fiscal Year Research-status Report
Understanding and development of highly efficient water splitting catalysts with core-shell structures for solar-hydrogen production
| Project/Area Number |
20K05684
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| Research Institution | Niigata University |
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Principal Investigator |
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| Project Period (FY) |
2020-04-01 – 2023-03-31
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| Keywords | FeNiW Catalysts |
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| Outline of Annual Research Achievements |
The critical bottleneck for sustainable production of hydrogen has remained in sluggish oxygen evolving reaction (OER), requiring insufficiently low overpotentials, η. We succeeded in reporting a facile and versatile method for the preparation of loading-controllable metal oxide films adhered rigidly on electrode substrates, enabling effectual material hunting for superior OER anodes. This allows us to discover a ternary FeNiWOx film on a nickel foam (NF), attaining one of the lowest overpotentials of η10 = 167 (The superscripts represent the attained current densities of 10 mA cm-2) with a Tafel slope of 49 mV dec-1 and at least 100 h stability in OER, which compare advantageously with only a few state-of-the-art OER anodes with excellent η10 < 200 mV. The electrochemical data indicate synergistic coupling among ternary metal centers of Ni, Fe and W to decrease the η value. The OER current is pH-dependent for the FeNiWOx film, showing the non-proton-concerted process in the rate-determining step for OER.
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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
The new method we discovered allowed us to investigate and design many catalysts for the water oxidation and allowed us to obtained most of the expected results. As an example, we succeeded in developing of a rigidly adhered nitrogen-doped BiVO4 photoanode with a narrow band gap energy (Eg = 2.35 eV) for water oxidation that attained the IPCE value of 35.1 % at 440 nm which is among the highest reported values. This electrode provides a very stable photocurrent density of 3.3 mA cm-2 at 1.23 V vs RHE for a long term (at least 13.4 h) under visible light irradiation (100 mW cm-2).
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| Strategy for Future Research Activity |
We plan to further Improve the OER performance of FeNiWOx via fabrication as a core-shell. The core will comprise of FeNiWXn (X = N, P, S, Se, and Te) and the shell comprises FeNiWOx that is formed by partial oxidation of X (X = N, P, S, Se, and Te) into O. The core provides a high conductivity medium for the electron flow from shell to nickel foam (NF), enhancing its OER performance.
we aim to investigate and enhance the HER performance of FeNiWXn and understand the active species (Fe, Ni, W, or combination of them) to develop more efficient catalysts.
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Research Products
(2 results)
