Detailed Analyses of Light Intensity Dependence to Uncover Multielectron Oxygen-Reduction Mechanism by Platinum-Loaded Tungsten(VI) Oxide

Abstract

Elucidation of the mechanism of multielectron transfer reactions, such as photocatalytic water oxidation and oxygen reduction, is essential for achieving high efficiency in the utilization of sustainable solar energy. Herein, we demonstrate that photocatalytic oxygen reduction on platinum-loaded tungsten(VI) oxide (Pt/WO₃) photocatalyst proceeds predominantly by two-electron transfer pathway under conventional light-intensity conditions. Light intensity-dependence analyses of the acetic acid decomposition reaction revealed the role of the Pt co-catalyst in enhancing overall quantum efficiency. We also report for the first time that the reaction can be initiated even on bare WO₃, in addition to Pt, under extremely high light-intensity conditions.

Keywords

Tungsten(VI) oxide / Platinum / Photocatalytic acetic-acid decomposition / Multielectron reactions / Light-intensity dependence / Kinetic model

CRediT authorship contribution statement

Author Contributions Conceptualization, B.O. and M.T.; Operation of photocatalytic reaction and data acquisition, C.Y.; Writing—Original Draft Preparation, C.Y. and M.T.; Writing—Review and Editing, all authors.

Availability of data and materials

Data Availability Statement Raw data were generated at Institute for Catalysis, Hokkaido University (North 21, West 10, Sapporo 001-0021, Japan). Derived data supporting the findings of this study are available from the corresponding author M.T. on request.

Funding

This research received no external funding.

Declaration of competing interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Acknowledgements

Acknowledgment As described in the Special Issue Information for A Commemorative Issue in Honor of Professor David Ollis: A Pioneer and Mentor, David had significantly advanced photocatalysis research by publishing papers, particularly in the field of kinetic analysis. The authors’ works, including the present paper, on the kinetic analysis of photocatalysis by clarifying the light-intensity dependence would not have been possible without the fruitful discussion with David at the scientific conferences. Here, we would like to express our deepest gratitude to the late David Ollis.

Appendix A. Supplementary data

Supplementary Materials The following supporting information can be found at: https://www.sciepublish.com/article/pii/898, Details on derivation of rate equations were described in Supplementary Materials.

References

[1] Ohtani B. Photocatalysis A to Z—What we know and what we do not know in a scientific sense. J. Photochem. Photobiol. C 2010, 11, 157-178. DOI:10.1021/ja00756a055

[2] Fleischauer PD, Alen Kan HK, Schepherd JR. Quantum yields of silver ion reduction on titanium dioxide and zinc oxide single crystals. J. Am. Chem. Soc. 1972, 94, 283-285. DOI:10.1021/ja00756a055

[3] Pruden AL, Ollis DF. Photoassisted heterogeneous catalysis: The degradation of trichloroethylene in water. J. Catal. 1983, 82, 404-417. DOI:10.1016/0021-9517(83)90207-5

[4] Ollis DF, Pelizzetti E, Serpone N. Photocatalyzed destruction of water contaminants. Environ. Sci. Technol. 1991, 25, 1522-1529. DOI:10.1021/es00021a001

[5] Ollis DF. Kinetics of liquid phase photocatalyzed reactions: An illuminating approach. J. Phys. Chem. B 2005, 109, 2439-2444. DOI:10.1021/jp040236f

[6] Abe R, Takami H, Murakami N, Ohtani B. Pristine simple oxides as visible light driven photocatalysts: Highly efficient decomposition of organic compounds over platinum-loaded tungsten oxide. J. Am. Chem. Soc. 2008, 130, 7780-7781. DOI:10.1021/ja800835q

[7] Chen H, Nanayakkara CE, Grassian VH. Titanium dioxide photocatalysis in atmospheric chemistry. Chem. Rev. 2012, 112, 5919-5948. DOI:10.1021/cr3002092

[8] Henderson MA, Lyubinetsky I. Molecular-level insights into photocatalysis from scanning probe microscopy studies on TiO₂ (110). Chem. Rev. 2013, 113, 4428-4455. DOI:10.1021/cr300315m

[9] Burek OB, Bahnemann WD, Bloh ZJ. Modeling and Optimization of the Photocatalytic Reduction of Molecular Oxygen to Hydrogen Peroxide over Titanium Dioxide. ACS Catal. 2019, 9, 25-37. DOI:10.1021/acscatal.8b03638

[10] Zuo G, Li B, Guo Z, Wang L, Yang F, Hou W, et al. Efficient photocatalytic hydrogen peroxide production over TiO₂ passivated by SnO₂. Catalysts 2019, 9, 623. DOI:10.3390/catal9070623

[11] Kobayashi H, Teranishi M, Negishi R, Naya S, Tada H. Reaction mechanism of the multiple-electron oxygen reduction reaction on the surfaces of gold and platinum nanoparticles loaded on titanium (IV) oxide. J. Phys. Chem. Lett. 2016, 7, 5002-5007. DOI:10.1021/acs.jpclett.6b02026

[12] Zhang Z, Wang X, Long J, Ding Z, Fu X, Fu X. H₂-O₂ promoting effect on photocatalytic degradation of organic pollutants in an aqueous solution without an external H₂ supply. Appl. Catal. A Gen. 2010, 380, 178-184. DOI:10.1016/j.apcata.2010.03.057

[13] Takeuchi S, Takashima M, Takase M, Ohtani B. Digitally controlled kinetics of titania-photocatalyzed oxygen evolution. Chem. Lett. 2018, 47, 373-376. DOI:10.1246/cl.171093

[14] Ketwong P, Yoshihara S, Takeuchi S, Takashima M, Ohtani B. Light intensity-dependence studies on the role of surface deposits for titania-photocatalyzed oxygen evolution: Are they really cocatalysts? J. Chem. Phys. 2020, 153, 124709. DOI:10.1063/5.0014913

[15] Hori H, Takashima M, Takase M, Ohtani B. Kinetic analysis supporting multielectron reduction of oxygen in bismuth tungstate-photocatalyzed oxidation of organic compounds. Catal. Today 2018, 313, 218-223. DOI:10.1016/j.cattod.2018.01.001

[16] Torimoto T, Aburakawa Y, Kawahara Y, Ikeda S, Ohtani B. Light intensity dependence of the action spectra of photocatalytic reactions with anatase titanium(IV) oxide. Chem. Phys. Lett. 2004, 392, 220-224. DOI:10.1016/j.cplett.2004.05.077