Multiphasic titanium dioxide (TiO2) possessing abundant heterophase junctions have been widely used for various photocatalytic applications. Current synthesis of multiphasic TiO2 mainly involves the process of thermal treatment and multiple steps of rigorous reactions, which is adverse to controlling the crystal phases and phase ratios of multiphasic TiO2. Meanwhile, the resulting products have relatively low surface area and nonporous structure. Here, a facile polymer‐assisted coordination‐mediated self‐assembly method to synthesize mesoporous TiO2 polymorphs with controllable heterophase junctions and large surface area by using polyethylenimine as the porogen in an acidic aqueous synthesis system is reported. Using this approach, the crystal phases (triphase, biphase, and monophase) and phase compositions (0–100%) are easily tailored by selecting the suitable acidic media. Furthermore, the specific surface areas (77–228 m2 g−1) and pore sizes (2.9–10.1 nm) are readily tailored by changing the reaction temperature. The photocatalytic activity of mesoporous TiO2 polymorphs is evaluated by photocatalytic hydrogen evolution. The triphasic TiO2 exhibits an excellent photocatalytic H2 generation rate of 3.57 mmol h−1 g−1 as compared to other polymorphs, which is attributed to the synergistic effects of heterophase junctions and mesostructure. The band diagram of possible electron transfer pathway for triphasic TiO2 is also elucidated.
Porous polymers with well‐orchestrated nanomorphologies are useful in many fields, but high surface area, hierarchical structure, and ordered pores are difficult to be satisfied in one polymer simultaneously. Herein, a solvent‐induced self‐assembly strategy to synthesize hierarchical porous polymers with tunable morphology, mesoporous structure, and microporous pore wall is reported. The poly(ethylene oxide)‐b‐polystyrene (PEO‐b‐PS) diblock copolymer micelles are cross‐linked via Friedel–Crafts reaction, which is a new way to anchor micelles into porous polymers with well‐defined structure. Varying the polarity of the solvent has a dramatic effect upon the oleophobic/oleophylic interaction, and the self‐assembly structure of PEO‐b‐PS can be tailored from aggregated nanoparticles to hollow spheres even mesoporous bulk. A morphological phase diagram is accomplished to systematically evaluate the influence of the composition of PEO‐b‐PS and the mixed solvent component on the pore structure and morphology of products. The hypercrosslinked hollow polymer spheres provide a confined microenvironment for the in situ reduction of K2PdCl4 to ultrasmall Pd nanoparticles, which exhibit excellent catalytic performance in solvent‐free catalytic oxidation of hydrocarbons and alcohols.
HIGHLIGHTS • Highly crystalline Mn 2 O 3 materials with tunable pore sizes are obtained and employed as high-performance cathode materials for reversible aqueous Zn-ion battery. • The Zn/Mn 2 O 3 battery exhibits significantly improved rate capability and remarkable cycling durability due to the introduction of nanoporous architecture. • The Zn 2+ /H + intercalations mechanism is put forward for the Zn/Mn 2 O 3 battery.
Triazine-based materials with porous structure have recently received numerous attentions as af ascinating new class because of their superior potential for various applications.H owever,i ti ss till af ormidable challenge to obtain triazine-based materials with precise adjustable meso-scaled pore sizes and controllable pore structures by reported synthesis approaches.H erein, we develop as olvent polarity induced interface self-assembly strategy to construct mesoporous triazine-based carbon materials.I nt his method, we employamixed solvent system within as uitable range of polarity (0.223 Lippert-Mataga parameter (Df) 0.295) to induce valid self-assembly of skeleton precursor and surfactant. The as-prepared mesoporous triazine-based carbon materials possess uniform tunable pore sizes (8.2-14.0 nm), high surface areas and ultrahigh nitrogen content (up to 18 %). Owing to these intriguing advantages,t he fabricated mesoporous triazine-based carbon materials as functionalizedporous solid absorbents exhibit predominant CO 2 adsorption performance and exceptional selectivity for the capture of CO 2 over N 2 .
Mesoporous transition metal oxides with high crystallinity and large pore volumes were successfully synthesized by a widely applicable ligand-assisted self-assembly approach. In this approach, a carboxyl-containing ligand is employed as a coordination agent to retard the hydrolysis and condensation rates of the precursors. The ligands interact with the PEO chains of P123 via hydrogen bonds, which cooperatively ensures the controllable co-assembly of template micelles and the metal source during solvent evaporation. The X-ray diffraction, transmission electron microscopy, and nitrogen sorption results show that the obtained mesoporous metal oxides are constructed from numerous highly crystalline nanoparticles and possess close-packed mesostructures with uniform pore size distributions. A series of mesoporous transition metal oxides (Co
Mesoporous metal oxides (MMOs) have attracted comprehensive attention in many fields, including energy storage, catalysis, and separation. Current synthesis of MMOs mainly involve use of surfactants as templates to generate mesopores and organic reagents as solvents to hinder hydrolysis and condensation of inorganic precursors, which is adverse to adjusting the interactions between surfactants and inorganic precursors. The resulting products have uncontrollable pore structure, crystallinity, and relatively lower surface areas. Here, a facile and general polymer‐oriented self‐assembly strategy to synthesize a series of MMOs (e.g., TiO
2
, ZrO
2
, NbO
5
, Al
2
O
3
, Ta
2
O
5
, HfO
2
, and SnO
2
) by using cationic polymers as porogens and metal alkoxides as metal oxide precursors in a robust aqueous synthesis system are reported. Nitrogen adsorption analysis and transmission electron microscopy confirm that the obtained MMOs have ultrahigh specific surface areas and large pore volumes (i.e., 733 m
2
g
−1
and 0.485 cm
3
g
−1
for mesoporous TiO
2
). Moreover, the structural parameters (surface area, pore size, and pore volume) and crystallinity can be readily controlled by tuning the interactions between cationic polymers and precursors. The as‐synthesized crystalline mesoporous TiO
2
exhibits promising performance in photocatalytic water splitting of hydrogen production and a high hydrogen production rate of 3.68 mol h
−1
g
−1
.
The designed synthesis of nanotwin architectures and thus-induced phase junctions expresses huge significance for semiconductor photocatalysts. However, current methods of producing nanotwins mainly involve high-temperature thermal treatment and tedious reaction steps, generally resulting in large bulk structure with ill-defined morphology and low specific surface area. Here, we propose a mild ligand-assisted coordinative self-assembly method to synthesize uniform mesoporous Zn x Cd 1−x S nanospheres with ultrahigh surface areas (148−312 m 2 g −1 ) and controllable diameter (90−370 nm). Moreover, the sample possesses abundant phase junctions induced by nanotwins containing both hexagonal and cubic segments. With the synergy of the twininduced phase junctions and high surface area, the as-prepared mesoporous Zn 0.82 Cd 0.18 S nanospheres exhibit a remarkable photocatalytic H 2 evolution rate of 13.46 mmol h −1 g −1 with free noble metal. The mechanism of photocarrier dynamics was studied by transient photovoltage spectroscopy, manifesting that the photocarrier lifetime of Zn 0.82 Cd 0.18 S is largely prolonged and therefore improves the charge separation efficiency and photocatalytic activity.
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