Mid-Infrared, Near-Infrared, and Visible Nanospectroscopy of Hydrogen-Intercalated MoO3
Jeffrey Schwartz, Sergiy Krylyuk, Devon Jakob, Albert Davydov, Andrea Centrone
Control over the local chemical composition and spatial heterogeneities in nanomaterials provides a means to impart new functions and to tailor their properties in many applications. For two-dimensional (2D) van der Waals materials, intercalation is one useful strategy to exert such control, by inserting or removing atomic, molecular, or ionic species in their lattice. For example, hydrogen intercalation and the creation of oxygen vacancies in MoO3 locally increase electrical conductivity, optical absorption, and electrochemical activity that find use in electrochromic, photochromic, catalytic, and energy storage applications. Here, after thermal annealing of MoO3 crystals in H2, we show that the resulting hydrogen molybdenum bronzes and/or oxygen deficient, substoichiometric molybdenum oxides (MoO3 ) displays highly heterogeneous, optically dark, topographically protruding patterns at the nanoscale. We leverage the nanoscale resolution of photothermal induced resonance absorption spectra and maps in the visible, mid-, and near-infrared to characterize these features that are spectrally distinct from the surrounding regions. Subsequent annealing in O2 enables partial recovery of the initial Mo:O stoichiometry, though some absorption peaks linked to intercalation persist. The high-resolution imaging and spectroscopic characterization employed here enable precise measurement of nanoscale heterogeneities and foster the adoption of 2D and other materials in advanced applications.
, Krylyuk, S.
, Jakob, D.
, Davydov, A.
and Centrone, A.
Mid-Infrared, Near-Infrared, and Visible Nanospectroscopy of Hydrogen-Intercalated MoO3, The Journal of Physical Chemistry C, [online], https://doi.org/10.1021/acs.jpcc.3c05114, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=936418
(Accessed September 26, 2023)