Active Sites for Light Driven Proton Reduction in Y2Ti2O7 and CsTaWO6 Pyrochlore Catalysts Detected by In Situ EPR
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In situ EPR spectroscopy proved to be a versatile tool to identify active sites for photocatalytic hydrogen generation in modified Y2Ti2O7 and CsTaWO6 catalysts of pyrochlore structure, in which the metal cations are located in two different positions A and B. It was found that the B-sites exclusively occupied by titanium (Y2Ti2O7) and tantalum/tungsten (CsTaWO6) act as electron traps on the surface. From these sites, electron transfer to the co-catalysts proceeds. Thus, the B-sites are responsible for photocatalytic water reduction.
KeywordsEPR Mechanism Electron transfer Pyrochlore Photocatalysis
This work has been supported by the German Science Foundation (DFG, WA 1116) and the Evonik Degussa GmbH (part-financed by the State of North Rhine-Westphalia and co-financed by the European Union Investing in our Future, European Regional Development Fund).
- 6.Takanabe K, Domen K (2011) Toward visible light response: overall water splitting using heterogeneous photocatalysts. Green 1(5–6):313–322Google Scholar
- 7.Maeda K, Xiong A, Yoshinaga T, Ikeda T, Sakamoto N, Hisatomi T, Takashima M, Lu D, Kanehara M, Setoyama T, Teranishi T, Domen K (2010) Photocatalytic overall water splitting promoted by two different cocatalysts for hydrogen and oxygen evolution under visible light. Angew Chem Int Ed 49(24):4096–4099CrossRefGoogle Scholar
- 19.Hollmann D, Grabow K, Jiao H, Kessler M, Spannenberg A, Beweries T, Bentrup U, Brückner A (2013) Hydrogen generation by water reduction with [Cp*2Ti(OTf)]: identifying elemental mechanistic steps by combined in situ FTIR and in situ EPR spectroscopy supported by DFT calculations. Chem Eur J 19(41):13705–13713CrossRefGoogle Scholar
- 27.Mabbs FE, Collison D (1999) The use of matrix diagonalization in the simulation of the EPR powder spectra of d-transition metal compounds. Mol Phys Rep 26:39–59Google Scholar
- 29.Hollmann D, Karnahl M, Tschierlei S, Kailasam K, Schneider M, Radnik J, Grabow K, Bentrup U, Junge H, Beller M, Lochbrunner S, Thomas A, Brückner A (2014) Structure-activity relationships in bulk polymeric and sol–gel-derived carbon nitrides during photocatalytic hydrogen production. Chem Mater 26(4):1727–1733CrossRefGoogle Scholar