Visible Light Locking in Mineral-Based Composite Phase Change Materials Enabling High Photothermal Conversion and Storage.

Fully stimulating the capacity of light-driven phase change materials (PCMs) for efficient capture, conversion, and storage solar energy requires an ingenious combination of PCMs, supporting structural materials, and photothermal materials, therefore motivating the synergistic effects between the components. Herein, this work thoroughly explores the interaction forces between PCMs and supporting structural materials and the synergy between PCMs and photothermal materials in photothermal conversion. Rejoicingly, when capitalizing on the prepared directional channel structure of hierarchically porous composite aerogel (PEPG) as a supporting structural material, a superior paraffin wax (PW) encapsulation rate of 85.11% is achieved, and the prepared PEPG2-PW has a high phase change enthalpy of 182.9 J/g. The van der Waals force and Lewis acid-base action between PEPG and PW molecules reveal the excellent stabilities of PEPG-PW. More importantly, the PEPG2-PW has an ultrahigh photothermal conversion efficiency of 95.2% under 1 sun irradiation and durability. Most importantly, the COMSOL Multiphysics software calculations demonstrate that transparent PW can anchor sunlight on the surface of graphite nanoplates, converting it into heat by enhancing the loss of graphite backbone lattice vibrations, and the accumulated heat is then stored in molten PW. This work provides some design principles for high-efficiency solar-thermal conversion materials.

Functionally constructed magnetic-dielectric mineral microspheres for efficient thermal energy storage and microwave absorption.

Electromagnetic interference (EMI) and equipment heat dissipation problems are becoming increasingly prominent in advanced applications such as modern wireless communications, driverless cars, and portable devices. Multifunctional composites with efficient energy storage, conversion, and microwave absorption are urgently needed. We reported an effective strategy to construct attapulgite (ATP), carbon nanotubes (CNT), and NiCo alloys composite mineral microspheres (ACNC). Urchin-like TiO2 was coated on the surface of ACNC to form composite microspheres (ACNCT), which was compounded with paraffin (P-ACNCT) to prepare thermal energy storage and microwave absorption integrated material. The urchin-like TiO2 morphology possesses unique advantages in encapsulating paraffin. The results show that the melting and solidification enthalpy of the P-ACNCT reaches 111.6 J/g and 108.1 J/g, respectively, which indicates excellent thermal energy storage capacity. Combining a dielectric TiO2 shell with a magnetic composite microsphere core can produce a core-shell microsphere mechanism that allows for adjustable reflection loss and promotes impedance matching. The effective microwave absorption bandwidth of P-ACNCT can reach 5.76 GHz when the thickness is only 1.6 mm in the 2-18 GHz range. P-ACNCT is significant for synchronous microwave absorption and thermal energy regulation of advanced electronic equipment.

Mineral-modulated Co catalyst with enhanced adsorption and dissociation of BH4- for hydrogenation of p-nitrophenol to p-aminophenol.

Slow adsorption and dissociation kinetics of NaBH4 onto the catalyst surface limit the hydrogenation reduction of hazardous p-nitrophenol to worthy p-aminophenol. Herein, we design a mineral-modulated catalyst to facilitate the rate-limiting step. Carbon-coated etched attapulgite (EAtp@C) is obtained by HF treatment. Co/EAtp@C is fabricated via anchoring cobalt nanoparticles (CoNPs) on the carrier EAtp@C. Compared to pure Co, the anchored CoNPs are more electronegative and stable, which provides abundant and stable active sites and accelerates the BH4- adsorption and dissociation. Therefore, Co/EAtp@C leads to nearly 100% reduction of p-nitrophenol to p-aminophenol within 8 min and its apparent rate constant Kapp (0.69 min-1) is 4 times higher than that of pure Co. Thermodynamic calculations show a lower activation energy (37.92 kJ mol-1) of Co/EAtp@C catalyst than that of pure Co. Co/EAtp@C also shows magnetic separability and good stability by remaining 98.6% of catalytic conversion rate after six cycles. Significantly, we detect the active species Co-H, and reveal the electron transfer mechanism between catalysts, BH4-, and p-nitrophenol by electrochemical method. These results offer a fundamental insight into the catalytic mechanism of p-nitrophenol hydrogenation for rational design of efficient catalysts.

Energetics, Interlayer Molecular Structures, and Hydration Mechanisms of Dimethyl Sulfoxide (DMSO)-Kaolinite Nanoclay Guest-Host Interactions.

Two-dimensional (2D) kaolinite nanoclay is an important natural mineral with promising application potential, especially tuned with organic intercalates. However, thus far, the organics-kaolinite guest-host interactions, the atomic scale structures of organic intercalates under confinement, and molecular level mechanisms of hydration are rarely systematically explored using both experimental and computational methodologies. We integrated density functional theory with dispersion scheme (DFT-D) with various experimental methods to investigate the intercalation of dimethyl sulfoxide (DMSO) in kaolinite with and without hydration. The kinetic, thermodynamic, and structural impacts of hydration were highlighted. In short, water molecules significantly promote intercalation of DMSO into kaolinite because of favorable intercalation energy, which is enabled by effective hydrogen bonding at the guest species (DMSO and water)-kaolinite interfaces.