Synergy-Compensation Effect of Ferroelectric Polarization and Cationic Vacancy Collaboratively Promoting CO2 Photoreduction

Unveiling Dynamic Structure and Bond Evolutions in BiOIO3 Photocatalysts during CO2 Reduction

We have established a correlation between photocatalytic activity and dynamic structure/bond evolutions of BiOIO3-based photocatalysts during CO2 reduction by combining operando X-ray diffraction with photoelectron spectroscopy. More specifically, the selective photo-deposition of PtOx species on BiOIO3 (010) facets could effectively promote the electron enrichment on Bi active sites of (100) facets for facilitating the adsorption/activation of CO2 molecules, leading to the formation of Bi sites with high oxidation state and the shrink of crystalline structures. With introducing light irradiation to drive CO2 reduction, the Bi active sites with high oxidation states transformed into normal Bi3+ state, accompanying with the expansion of crystalline structures. Owing to the dynamic structure, bond, and chemical-state evolutions, a significant improvement of photocatalytic activity for CO evolution has been achieved on PtOx-BiOIO3 (195.0 μmol g-1 ⋅ h-1), much higher than the pristine (61.9 μmol g-1 ⋅ h-1) as well as metal-Pt decorated BiOIO3 (70.3 μmol g-1 ⋅ h-1) samples. This work provides new insights to correlate the intrinsically dynamic structure/bond evolutions with CO2 reduction activity, which may help to guide future photocatalyst design.

2D Atomic Layers for CO2 Photoreduction

Artificial photosynthesis can convert carbon dioxide into high value-added chemicals. However, due to the poor charge separation efficiency and CO2 activation ability, the conversion efficiency of photocatalytic CO2 reduction is greatly restricted. Ultrathin 2D photocatalyst emerges as an alternative to realize the higher CO2 reduction performance. In this review, the basic principle of CO2 photoreduction is introduced, and the types, advantages, and advances of 2D photocatalysts are reviewed in detail including metal oxides, metal chalcogenides, bismuth-based materials, MXene, metal-organic framework, and metal-free materials. Subsequently, the tactics for improving the performance of 2D photocatalysts are introduced in detail via the surface atomic configuration and electronic state tuning such as component tuning, crystal facet control, defect engineering, element doping, cocatalyst modification, polarization, and strain engineering. Finally, the concluding remarks and future development of 2D photocatalysts in CO2 reduction are prospected.

Research progress on photocatalytic reduction of CO2 based on ferroelectric materials

Transforming CO2 into renewable fuels or valuable carbon compounds could be a practical means to tackle the issues of global warming and energy crisis. Photocatalytic CO2 reduction is more energy-efficient and environmentally friendly, and offers a broader range of potential applications than other CO2 conversion techniques. Ferroelectric materials, which belong to a class of materials with switchable polarization, are attractive candidates as catalysts due to their distinctive and substantial impact on surface physical and chemical characteristics. This review provides a concise overview of the fundamental principles underlying photocatalysis and the mechanism involved in CO2 reduction. Additionally, the composition and properties of ferroelectric materials are introduced. This review expands on the research progress in using ferroelectric materials for photocatalytic reduction of CO2 from three perspectives: directly as a catalyst, by modification, and construction of heterojunctions. Finally, the future potential of ferroelectric materials for photocatalytic CO2 reduction is presented. This review may be a valuable guide for creating reasonable and more effective photocatalysts based on ferroelectric materials.

Reinforcing the Efficiency of Photothermal Catalytic CO2 Methanation through Integration of Ru Nanoparticles with Photothermal MnCo2O4 Nanosheets

Carbon dioxide (CO2) hydrogenation to methane (CH4) is regarded as a promising approach for CO2 utilization, whereas achieving desirable conversion efficiency under mild conditions remains a significant challenge. Herein, we have identified ultrasmall Ru nanoparticles (∼2.5 nm) anchored on MnCo2O4 nanosheets as prospective photothermal catalysts for CO2 methanation at ambient pressure with light irradiation. Our findings revealed that MnCo2O4 nanosheets exhibit dual functionality as photothermal substrates for localized temperature enhancement and photocatalysts for electron donation. As such, the optimized Ru/MnCo2O4-2 gave a high CH4 production rate of 66.3 mmol gcat-1 h-1 (corresponding to 5.1 mol gRu-1 h-1) with 96% CH4 selectivity at 230 °C under ambient pressure and light irradiation (420-780 nm, 1.25 W cm-2), outperforming most reported plasmonic metal-based catalysts. The mechanisms behind the intriguing photothermal catalytic performance improvement were substantiated through a comprehensive investigation involving experimental characterizations, numerical simulations and density functional theory (DFT) calculations, which unveiled the synergistic effects of enhanced charge separation efficiency, improved reaction kinetics, facilitated reactant adsorption/activation and accelerated intermediate conversion under light irradiation over Ru/MnCo2O4. A comparison study showed that, with identical external input energy during the reaction, Ru/MnCo2O4-2 had a much higher catalytic efficiency compared to Ru/TiO2 and Ru/Al2O3. This study underscores the pivotal role played by photothermal supports and is believed to engender a heightened interest in plasmonic metal nanoparticles anchored on photothermal substrates for CO2 methanation under mild conditions.

Strain-Engineering of Mesoporous Cs3 Bi2 Br9 /BiVO4 S-Scheme Heterojunction for Efficient CO2 Photoreduction

Slow charge kinetics and unfavorable CO₂ adsorption/activation strongly inhibit CO₂ photoreduction. In this study, a strain-engineered Cs₃ Bi₂ Br₉ /hierarchically porous BiVO₄ (s-CBB/HP-BVO) heterojunction with improved charge separation and tailored CO₂ adsorption/activation capability is developed. Density functional theory calculations suggest that the presence of tensile strain in Cs₃ Bi₂ Br₉ can significantly downshift the p-band center of the active Bi atoms, which enhances the adsorption/activation of inert CO₂ . Meanwhile, in situ irradiation X-ray photoelectron spectroscopy and electron spin resonance confirm that efficient charge transfer occurs in s-CBB/HP-BVO following an S-scheme with built-in electric field acceleration. Therefore, the well-designed s-CBB/HP-BVO heterojunction exhibits a boosted photocatalytic activity, with a total electron consumption rate of 70.63 µmol g^-1 h^-1 , and 79.66% selectivity of CO production. Additionally, in situ diffuse reflectance infrared Fourier transform spectroscopy reveals that CO₂ photoreduction undergoes a formaldehyde-mediated reaction process. This work provides insight into strain engineering to improve the photocatalytic performance of halide perovskite.