Tailoring the Surface Properties of Bi
| Autor: | Piotr Kuśtrowski, Caspar N. de Bruin-Dickason, Alex J. Corkett, Jianhong Chen, Zheng Chen, Richard Dronskowski, Anna Rokicińska, Adam Slabon |
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| Rok vydání: | 2020 |
| Předmět: |
Photocurrent
010405 organic chemistry Scanning electron microscope chemistry.chemical_element Electrolyte 010402 general chemistry 01 natural sciences Article 0104 chemical sciences Bismuth Inorganic Chemistry X-ray photoelectron spectroscopy chemistry Chemical engineering ddc:540 Scanning transmission electron microscopy Reversible hydrogen electrode Physical and Theoretical Chemistry Thin film |
| Zdroj: | Inorganic chemistry 59(18), 13589-13597 (2020). doi:10.1021/acs.inorgchem.0c01947 Inorganic Chemistry |
| ISSN: | 1520-510X |
| DOI: | 10.1021/acs.inorgchem.0c01947 |
| Popis: | Bismuth(III) oxide-carbodiimide (Bi2O2NCN) has been recently discovered as a novel mixed-anion semiconductor, which is structurally related to bismuth oxides and oxysulfides. Given the structural versatility of these layered structures, we investigated the unexplored photochemical properties of the target compound for photoelectrochemical (PEC) water oxidation. Although Bi2O2NCN does not generate a noticeable photocurrent as a single photoabsorber, the fabrication of heterojunctions with the WO3 thin film electrode shows an upsurge of current density from 0.9 to 1.1 mA cm–2 at 1.23 V vs reversible hydrogen electrode (RHE) under 1 sun (AM 1.5G) illumination in phosphate electrolyte (pH 7.0). Mechanistic analysis and structural analysis using powder X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and scanning transmission electron microscopy energy-dispersive X-ray spectroscopy (STEM EDX) indicate that Bi2O2NCN transforms during operating conditions in situ to a core–shell structure Bi2O2NCN/BiPO4. When compared to WO3/BiPO4, the in situ electrolyte-activated WO3/Bi2O2NCN photoanode shows a higher photocurrent density due to superior charge separation across the oxide/oxide-carbodiimide interface layer. Changing the electrolyte from phosphate to sulfate results in a lower photocurrent and shows that the electrolyte determines the surface chemistry and mediates the PEC activity of the metal oxide-carbodiimide. A similar trend could be observed for CuWO4 thin film photoanodes. These results show the potential of metal oxide-carbodiimides as relatively novel representatives of mixed-anion compounds and shed light on the importance of the control over the surface chemistry to enable the in situ activation. Phosphate electrolyte activates the metal oxide−Bi2O2NCN heterojunction. |
| Databáze: | OpenAIRE |
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