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 Bi_xIn_2-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 Bi_xIn_2-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.

Titanium dioxide is the only known material that can enable gas-phase CO₂ photocatalysis in its anatase and rutile polymorphic forms. Materials engineering of polymorphism provides a useful strategy for optimizing the performance metrics of a photocatalyst. In this paper, it is shown that the less well known rhombohedral polymorph of indium sesquioxide, like its well-documented cubic polymorph, is a CO₂ hydrogenation photocatalyst for the production of CH₃OH and CO. Significantly, the rhombohedral polymorph exhibits higher activity, superior stability and improved selectivity towards CH₃OH over CO. These gains in catalyst performance originate in the enhanced acidity and basicity of surface frustrated Lewis pairs in the rhombohedral form.

The developed α-Fe ₂ O ₃ /CQD@g-C ₃ N ₄ can perform a direct one-step two-electron reduction for efficient photocatalytic H ₂ O ₂ evolution in pure water.

Rh/c-In ₂ O _{3− x} (OH) _y with precisely adjustable fractions of rhombohedral and cubic phases were synthesized and enabled boosting photocatalytic performance toward CO ₂ hydrogenation.

M/Ag₃PO₄ (M = Pt, Pd, Au) Schottky-type heterostructures were successfully fabricated by a chemical deposition route using NaBH₄ as a reduction agent. The structure and optical properties of the as-synthesized samples were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, UV-vis diffuse reflectance spectroscopy, and electrochemical techniques. The photocatalytic activity was evaluated by the decomposition of dyes (methyl orange, methylene blue, and rhodamine B) under visible light irradiation (λ > 420 nm). These noble metals as nanoparticles were highly dispersed on the surface of Ag₃PO₄ polyhedrons. The light absorption of Ag₃PO₄ in both the UV and visible regions was extensively increased upon noble metal deposition. The photocurrent response over M/Ag₃PO₄ electrodes was much higher than that of pure Ag₃PO₄ and followed the decreased order of Pt > Pd > Au. The metallic nanoparticles deposited on Ag₃PO₄ could promote the transfer of photo-generated electrons, which not only inhibited the recombination of electrons and holes effectively, but also suppressed the photocorrosion of Ag₃PO₄, leading to a significant increase in photocatalytic activity and stability. On the basis of radical-trapping experiments and the PL technique, h⁺ and ˙O₂ ⁻ were well-established to correspond to the quick photo-degradation of dyes and a possible mechanism was proposed.