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• Nanostructure TiO2-reduced graphene oxide composite aerogels (rGO-TA) were synthesized. • The rod-like TiO 2 with a width of 10–20 nm and length of 100–150 nm are decorated on the network structure of rGO aerogel. • In-situ rGO-TA composite exhibited highest visible light absorption. • Anchoring of oxygen vacancies and C-O-Ti bond contribute to the enhanced activity. • The highest carbon conversion of composite aerogel was 15.7 times than that of P25. ga1 In response to the worldwide over-standard carbon dioxide emission problem, this work synthesized a series of titanium dioxide/reduced graphene oxide composite aerogels (TiO 2 -rGO) for photoconversion of CO 2 by a one-step hydrothermal and freeze-drying method. The prepared composite aerogel presents a high specific surface area of 287.3 m2/g and pore volume of 0.72 cm3/g, contributing to remarkable absorption capability of reactants and fast intraparticle molecular transfer. In the three-dimensional structure of rGO aerogel, TiO 2 with nano-rod shape (10–20 nm × 100–150 nm) is uniformly interspersed. Through applying the composite catalytic aerogel for the photocatalysis reaction, CO 2 was efficiently converted to MeOH, CH 4 , and EtOH, etc. The total yield of carbon generated by G-25Ti (TiO 2 -rGO with 25 mmol Ti4+) was found 15.7 times higher than that of the pure P25. The corresponding characteristic analysis demonstrated that the photocatalytic performance of TiO 2 -rGO composite aerogel has been highly improved, originated from two folds: (1) the introduction of 3-D rGO to nano-rod shape TiO 2 promoted its light absorption efficiency, and more significantly (2) the specific chemical bonding sites and strong O˭C‒O‒Ti group between rGO and TiO 2 effectively mitigate the recombination of photogenerated electron–hole pairs. In this work, rod-like TiO 2 -rGO composite aerogels prepared by using TiCl 4 as precursor for the first time have been found a new application in CO 2 reduction using visible sunlight. [ABSTRACT FROM AUTHOR]

The applications of silica aerogels are restricted due to their intrinsic fragile property. Polymerization of di-isocyanates can be templated onto the mesoporous surface of the –NH 2 group modified silica clusters, resulting in the conformal crosslinked coating on surface of silica clusters. Aminopropyltriethoxysilane (APTES), as the silica co-precursor and amine group modification agent, is involved containing tetramethyl orthosilicate (TMOS) silica precursor, while hexamethylene diisocyanate (HDI) is incorporated as the polymer crosslinking agent. The effects of different amounts of APTES on the physicochemical properties of the resulting crosslinked aerogels are investigated. The results show that the optimized APTES/TMOS volume ratio can be determined at 0.5:1. The resulting optimal crosslinked silica aerogel possesses large BET specific surface area of 150.9 m2/g, low thermal conductivity of 0.037 W/(m·K), and the Young's modulus is as large as 18 MPa under strain of 4.2%, much higher than that in the previously published works. The polymerization reaction mechanism forming the polyurethane chains has also been proposed. In addition, the interactions between silica clusters and polymer chains are studied by molecular mechanics and molecular dynamics. The interactions are mainly dependent on non-bonding energy, and the electrostatic energy has decisive impact on the combination of silica clusters and polymer chains. The density field of C, H, N, O, and Si elements overlaps with each other, indicating that the polymer crosslinked silica aerogel maintains typical three-dimensional porous structure. The N element enriches in the region between silica clusters, further verifying the formation –CONH–(CH 2) 6 –CONH- polyurethane chains, which is actually responsible for the much enhanced mechanical property. [ABSTRACT FROM AUTHOR]

Practical applications of silica aerogels have been restricted due to their hydrophilicity, fragility and high cost of supercritical drying technique. In this work, the successful synthesis of the super hydrophobic polymethylsilsesquioxane (PMSQ) based silica aerogel via the sol-gel technique and ambient pressure drying method is proposed. Dimethoxydimethylsilane (DMDMS) and methyltrimethoxysilane (MTMS) are used as the co-precursors. The MTMS/DMDMS volume ratio is determined at 3/1, and the water contact angle as large as 165°, confirming its super hydrophobicity. The CH 3 groups rendering the hydrophobicity gradually disappear after heat treatment at 400 °C. The aerogel is composed of the spherical and smooth secondary particles with diameters at around 3–4 μm, with the most probable pore diameter locating at around 20 μm. The aerogel exhibits excellent elastic property under compression cycling test. Moreover, it displays good adsorption properties over many kinds of organic solvents, as well as excellent cycling adsorption property. Schemicatic diagram of the formation for the superhydrophobic and flexible PMSQ based silica aerogel. Unlabelled Image • A novel PMSQ-based aerogel is prepared via ambient pressure drying technique. • The mechanism of hydrophobicity evolution and flexible aerogel formation is proposed. • The aerogel has a high contact angle of 165° and excellent flexibility under compression cycling test. [ABSTRACT FROM AUTHOR]

Biomass aerogel is attractive in various applications due to their renewable, biodegradable and eco-friendly advantages. Herein, a novel beta molecular sieve/carboxymethyl cellulose/polyvinyl alcohol composite aerogel (beta/CP) is prepared by direct mixing and directional freeze-drying as an efficient gas adsorbent with hierarchical porosity. The beta molecular sieve is uniformly dispersed in the three-dimensional skeleton of the aerogel. By adjusting the loading mass of the beta molecular sieve to constitute a reasonable porosity and pore size distribution, the synergistic effect between pore structures of different scales improves the adsorption performance. The experiment results of beta/CP-4 show that the CH 4 adsorption capacity can reach 60.33 cm3/g at 298 K and 100 bar, which is almost the same as that of the pure beta molecular sieve (62.09 cm3/g). The strong interaction between the aerogel and it prevents the molecular sieve agglomeration, improves the pore utilization, and also reduces the cost of using molecular sieve adsorbent. The above results indicate that the composite has good potential for application in the field of CH 4 storage. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • SAM aerogel is prepared by directional freeze-drying method. • Tuning carbonization temperature and activator ratio to optimize performance. • SAM-700-4 shows 3D interconnected structure with large specific surface area. • SAM-700-4 shows excellent specific capacitance of 441.80 F/g at 0.5 A/g. • SAM-700-4//SAM-700-4 all-solid-state supercapacitor exhibit high energy density. Hierarchical porous carbon shows great potential in the field of energy storage due to high porosity, large surface area, and excellent electrical conductivity. Here, we successfully fabricated carbon aerogel derived from sodium alginate/melamine composite (SAM) by directional freeze-drying combined with simple carbonization and activation process. The optimal SAM-700-4 possesses a high nitrogen (5.67 at.%) and oxygen (8.98 at.%) contents along with high specific surface area of 2577.62 m2/g and unique directional channel structure. Due to their synergistic effect, the SAM-700-4 electrode exhibits a high specific capacitance of 441.80 F/g at a current density of 0.5 A/g. Interestingly, the all-solid-state symmetric supercapacitor based on SAM-700-4//SAM-700-4 in PVA/SA/KOH gel electrolyte has a large energy density of 20.87 Wh/kg at a power density of 4000 W/kg and exhibits excellent cycling stability. It is believed that this N, O co-doped directional hierarchical porous carbon aerogel may show promising prospects as advanced energy storage materials. [ABSTRACT FROM AUTHOR]