Abstract
The surface frustrated Lewis pairs (SFLPs) on defect-laden metal oxides provide catalytic sites to activate H2 and CO2 molecules and enable efficient gas-phase CO2 photocatalysis. Lattice engineering of metal oxides provides a useful strategy to tailor the reactivity of SFLPs. Herein, a one-step solvothermal synthesis is developed that enables isomorphic replacement of Lewis acidic site In3+ ions in In2O3 by single-site Bi3+ ions, thereby enhancing the propensity to activate CO2 molecules. The so-formed BixIn2-xO3 materials prove to be three orders of magnitude more photoactive for the reverse water gas shift reaction than In2O3 itself, while also exhibiting notable photoactivity towards methanol production. The increased solar absorption efficiency and efficient charge-separation and transfer of BixIn2-xO3 also contribute to the improved photocatalytic performance. These traits exemplify the opportunities that exist for atom-scale engineering in heterogeneous CO2 photocatalysis, another step towards the vision of the solar CO2 refinery.
Highlights
The surface frustrated Lewis pairs (SFLPs) on defect-laden metal oxides provide catalytic sites to activate H2 and CO2 molecules and enable efficient gas-phase CO2 photocatalysis
Transmission electron microscopy (TEM) shows that the pristine In2O3 nanocrystals are flower-like agglomerates of small nanocrystals with an average size of 3.7 nm (Supplementary Fig. 1)
Spherical aberration-corrected scanning transmission electron microscopy (STEM) images provide an insightful and distinct result, in which atomically dispersed single-site Bi atoms are revealed under these high-resolution imaging conditions as bright dots (Fig. 1a, b)
Summary
The surface frustrated Lewis pairs (SFLPs) on defect-laden metal oxides provide catalytic sites to activate H2 and CO2 molecules and enable efficient gas-phase CO2 photocatalysis. The photocatalytic hydrogenation of CO2 into value-added chemicals and fuels has attracted global attention, touted a promising means of achieving a carbonneutral economy[1,2,3] Materials such as Pd/Nb2O54, Ru/ Al2O35, LDH nanosheets[6], and Co-PS@SiO27 have been successfully employed as photocatalysts for CO2 hydrogenation, a photocatalyst does not currently exist that can meet all the stringent requirements for practical application, including a broad solar response, high conversion efficiency, robust stability and low cost. Tailoring the electronic properties of In2O3 can be achieved via replacement of an indium atom in the lattice with a H2 spillover palladium atom, the rarity and cost of palladium could prove an issue for its practical implementation[24]
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