In Situ Chemical Oxidation of Ultrasmall MoOx Nanoparticles in Suspensions

Figure 3

Effect of chemical oxidation conditions on MoO_𝑥 nanoparticle stoichiometry. (a) Mo 3d XPS spectra of as-synthesized npMoO_𝑥 on ITO (crosses) and curve fit (solid), showing mixed oxidation states with contributions from Mo⁵⁺, Mo⁴⁺, and a small amount of Mo⁶⁺. (b) Mo 3d XPS spectra of npMoO_𝑥 after chemical oxidation with 0.05 M H₂O₂ for 1 hr, showing mixed oxidation states with a majority of Mo⁶⁺ oxidation state. (c) Mo 3d XPS spectra of npMoO_𝑥 after chemical oxidation with 0.1 M H₂O₂ for 1 hr, showing almost complete oxidation to Mo⁶⁺ oxidation state. (d) Mo 3d XPS spectra of npMoO_𝑥 after chemical oxidation with 0.1 M H₂O₂ for 24 hr, showing mixed oxidation states with a majority of Mo⁶⁺ oxidation state.

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