Z-Scheme Photocatalyst Constructed by Natural Attapulgite and Upconversion Rare Earth Materials for Desulfurization

The Er3+:CeO2/ATP (attapulgite) nanocomposites were prepared by a facile precipitation method. The samples were characterized by various measurements. XRD and TEM showed that Er3+:CeO2 nanoparticles were well-crystallized and loaded on the surface of ATP. The visible light was converted into ultraviolet light by Er3+:CeO2 as evidenced by upconversion photoluminance (PL) analysis. The mass ratio of Er3+:CeO2 to ATP on the desulfurization efficiency was investigated. Results showed that the desulfurization rate reached 87% under 4 h visible light irradiation when the mass ratio was 4:10. The mechanism was put forward as follows. Er3+:CeO2 and ATP formed Z-scheme heterostructure intermediated by oxygen vacancy, leading to the enhanced separation of photogenerated charges and preservation of high oxidation-reduction potential, both of which favored for the generation of radicals to oxidize sulfur species

Photothermal Catalytic Reduction of CO₂ by Cobalt Silicate Heterojunction Constructed from Clay Minerals

The coupled utilization of solar and thermal energy is considered an efficient way to improve the efficiency of CO2 reduction. Herein, palygorskite (Pal) clay is as a silicon source, while Co2+ is introduced to prepare two-dimensional Co2SiO4 nanosheets, and the excess of Co2+ leads to the growth of Co3O4 on the surface of Co2SiO4 to obtain an S-scheme Co2SiO4/Co3O4−x heterojunction, which facilitates the charge transfer and maintains higher redox potentials. Benefiting from black color and a narrow band gap, the cobalt oxide on the surface can increase the light absorption and produce a local photothermal effect. Under proper thermal activation conditions, the photoelectrons captured by the abundant oxygen vacancies can obtain a secondary leap to the semiconductor conduction band (CB), suppressing the recombination of electron-hole pairs, thus favoring the electron transfer on Co2SiO4/Co3O4−x. The composites not only have abundant oxygen vacancies, but also have a large specific surface area for the adsorption and activation of CO2. The yields of CH3OH on Co2SiO4/Co3O4−5% reach as high as 48.9 μmol·g−1·h−1 under simulated sunlight irradiation. In situ DRIFTS is used to explore the photocatalytic reduction CO2 mechanism. It is found that the thermal effect facilitates the generation of the key intermediate COOH* species. This work provides a new strategy for photothermal catalytic CO2 reduction by taking advantage of natural clay and solar energy

Thermally Conductive 3D-Printed Carbon-Nanotube-Filled Polymer Nanocomposites for Scalable Thermal Management

Thermal transportation in a preferred direction is desirable and important for addressing thermal management issues. With the merits of high thermal conductivity, good chemical stability, and desirable mechanical properties, carbon nanotubes (CNTs) have a great potential for wide applications in heat dissipation devices. The combination of 3D printing and CNTs can enable unlimited possibilities for hierarchically aligned structural programming. We report the formation of through-plane aligned multiwalled CNT (MWCNT)-filled polylactic acid (PLA) nanocomposites by 3D printing. The as-printed vertically (or through-plane) aligned structure demonstrates a through-plane thermal conductivity (k⊥) of ∼0.575 W/(mK) at 20 wt % MWCNT content, which is around 2.64 times that of a horizontally aligned structure (∼0.218 W/(mK)) and around 5.87 times that of neat PLA (∼0.098 W/(mK)) at 35 °C. Infrared thermal imaging performed on 3D-printed MWCNT/PLA heat sink verified the superior performance of the nanocomposite compared to that of the matrix polymer. In this study, we achieved the manufacturing of MWCNT/PLA with a high filler loading and a significant improvement in thermal conductivity simultaneously. This work paves the way to develop 3D-printed carbon filler-reinforced polymer composites for thermal-related applications such as heat sinks or thermal radiators