The solvent-driven formation of multi-morphological Ag–CeO2 plasmonic photocatalysts with enhanced visible-light photocatalytic reduction of CO2

Visible-light driven reaction of CO2 with alcohols using a Ag/CeO2 nanocomposite: first photochemical synthesis of linear carbonates under mild conditions

The first photochemical synthesis of linear carbonates from the reaction of CO₂ with alcohols using a silver-doped ceria nanocomposite at room temperature under visible light irradiation is described. DFT calculations suggested the electron transfer from Ag 4d states to Ce 4f states in the composite for the photoreaction.

Recent advances and perspectives of CeO2-based catalysts: Electronic properties and applications for energy storage and conversion

Cerium dioxide (CeO₂, ceria) has long been regarded as one of the key materials in modern catalysis, both as a support and as a catalyst itself. Apart from its well-established use (three-way catalysts and diesel engines), CeO₂ has been widely used as a cocatalyst/catalyst in energy conversion and storage applications. The importance stems from the oxygen storage capacity of ceria, which allows it to release oxygen under reducing conditions and to store oxygen by filling oxygen vacancies under oxidizing conditions. However, the nature of the Ce active site remains not well understood because the degree of participation of f electrons in catalytic reactions is not clear in the case of the heavy dependence of catalysis theory on localized d orbitals at the Fermi energy E _F . This review focuses on the catalytic applications in energy conversion and storage of CeO₂-based nanostructures and discusses the mechanisms for several typical catalytic reactions from the perspectives of electronic properties of CeO₂-based nanostructures. Defect engineering is also summarized to better understand the relationship between catalytic performance and electronic properties. Finally, the challenges and prospects of designing high efficiency CeO₂-based catalysts in energy storage and conversion have been emphasized.

Plasmonic Photocatalysts for Sunlight-Driven Reduction of CO2 : Details, Developments, and Perspectives

Plasmonic photocatalysis is among the most efficient processes for the photoreduction of CO₂ into valuable fuels. The formation of localized surface plasmon resonance (LSPR), energy transfer, and surface reaction are the significant steps in this process. LSPR plays an essential role in the performance of plasmonic photocatalysts as it promotes an excellent, light absorption over a broad wavelength range while simultaneously facilitating an efficient energy transfer to semiconductors. The LSPR transfers energy to a semiconductor through various mechanisms, which have both advantages and disadvantages. This work points out four critical features for plasmonic photocatalyst design, that is, plasmonic materials, size, shape of plasmonic nanoparticles (PNPs), and the contact between PNPs and semiconductor. Various developed plasmonic photocatalysts, as well as their photocatalytic performance in CO₂ photoreduction, are reviewed and discussed. Finally, perspectives of advanced architectures and structural engineering for plasmonic photocatalyst design are put forward with high expectations to achieve an efficient CO₂ photoreduction shortly.

Construction of Embedded Heterostructured SrZrO3/Flower-like MoS2 with Enhanced Dye Photodegradation under Solar-Simulated Light Illumination

SrZrO3/flower-like MoS2 composites with an embedded heterostructure were synthesized via a simple two-step hydrothermal method and their performance was evaluated by photodegradation of methylene blue (MB) under solar-simulated light irradiation. The sandwiched flower-like MoS2 with a high Mo(VI) ratio was adopted as the matrix, and SrZrO3 was grown between the MoS2 layers, forming an intense contact interface, which promotes the efficient separation and transport of photoinduced carriers. The enhanced photocatalytic degradation of 99.7% after 80 min of irradiation is exhibited over the MS5 sample (5 wt % SrZrO3 loading amount on the MoS2 matrix). Moreover, the ratio of Mo(VI) and the superoxide radical plays a crucial role in the photodegradation of MB, and the higher the ratio the better the performance. This work provided a strategy to design a new kind of photocatalyst for photocatalysis and indicated that MoS2 is preferably adopted as a matrix rather than as a loading component.

Facile strategy for the fabrication of noble metal/ZnS composites with enhanced photocatalytic activities

The introduction of noble metal nanoparticles to photocatalysts can effectively improve the separation efficiency of the photogenerated electron–holes. Therefore, noble metal/ZnS composites were synthesized using a low-temperature solid-phase chemical method with sodium borohydride as the reducing agent. The characterization results showed that the noble metal/ZnS composites have been successfully obtained and that the noble metals were distributed on the surface of ZnS. The catalytic results suggested that the composites exhibited improved activity after introduction of noble metals, which can be attributed to the rapid migration of carriers and the enhancement of the light absorption, mainly owing to the tight combination between the ZnS and noble metals and the plasmon resonance effect of the noble metals. The catalytic mechanism was explored by using photoluminescence spectroscopy, photocurrent spectra, valence band X-ray photoelectron spectroscopy (XPS-VB) spectra and capture agent experiments, and a possible mechanism was proposed. This work provides a new strategy for the high-volume synthesis of noble metal-based composite photocatalysts, which could be helpful for sustainable development.

The introduction of noble metal nanoparticles to photocatalysts can effectively improve the separation efficiency of the photogenerated electron–holes.

Improved in Situ Synthesis of Heterostructured 2D/2D BiOCl/g-C3N4 with Enhanced Dye Photodegradation under Visible-Light Illumination

A simple, in situ, and one-pot hydrothermal strategy was applied for the successful manufacturing of heterostructured 2D/2D BiOCl/g-C3N4 photocatalysts, and outstanding photodegradation of Rhodamine B in the condition of visible-light irradiation over the composites emerged. The investigation of various BiOCl/g-C3N4 ratios influencing the activity implied that the optimized B2C1 (mole ratio of BiOCl/g-C3N4 with 2:1) exhibited the higher degradation efficiency than that of the rest of the composites, even higher than that of pure BiOCl and pure g-C3N4, which yielded over 90% in the initial 30 min and reached almost 100% during the whole 70 min irradiation process. Kinds of characterizations demonstrated that the enhancement of photodegradation performance was caused by the intimate contact between BiOCl and g-C3N4 to form the heterostructure, which could benefit the generation of abundant visible-light photoinduced carriers and help enhance their separation and then promote their transportation to the surface.

A Highly Efficient Composite Catalyst Constructed From NH2-MIL-125(Ti) and Reduced Graphene Oxide for CO2 Photoreduction

Substantial consumption of fossil fuels causes an increase in CO2 emissions and intensifies global pollution problems, such as the greenhouse effect. Recently, a new type of ultra-low-density porous material, metal-organic frameworks (MOFs), has been developed for the photocatalytic conversion of CO2. Herein, a composite photocatalytic catalyst based on NH2-MIL-125(Ti) and reduced graphene oxide (rGO@NH2-MIL-125) was fabricated through a facile "one-pot" process. The acquired materials were characterized to obtain their structures, morphologies, and optical information. The experimental results showed that methyl formate (MF) was the predominant reaction product, and rGO@NH2-MIL-125 exhibited the highest yield of 1,116 μmol·g-1·h-1, more than twice that of pure MIL-125. The high photoactivity of rGO@NH2-MIL-125 can be ascribed to the effective spatial separation and transfer of photoinduced carriers, largely due to the synergistic effect of amino functionality and rGO incorporation. rGO@NH2-MIL-125 also displayed acceptable repeatability in cyclic runs for CO2 reduction.