A simple and general procedure has been developed for the syntheses of ordered largepore (up to 14 nm) mesoporous metal oxides, including

At present, more than 80% of the energy consumed globally is derived from non-renewable fossil fuels such as coal, oil and natural gas. The combustion of these fuels inevitably leads to the emission of CO 2 -a main driver of climate change and other serious environmental effects, including the emission of other dangerous gases. Although mitigating climate change is a multifaceted challenge, one of the pillars of any future low-carbon economy will be a substantially increased dependence on renewable and environmentally friendly energy sources and storage systems. Tremendous progress is being made in developing advanced technologies to meet these challenges. However, to enable the cost-effective, large-scale production of these technologies, further improvement of performance and efficiency is needed. Although unique challenges exist for each technology, the development of functional materials is crucial.Porous solids -in particular, mesoporous solids -are appealing materials in many energy applications owing to their ability to absorb and interact with guest species (including, but not limited to, lithium ions, hydrogen atoms and sulfur molecules) on their outer and inner surfaces, and in the pore spaces 1,2 . According to the International Union of Pure and Applied Chemistry (IUPAC) definition, porous materials are classified into three categories according to their pore sizes: micro porous (<2 nm), mesoporous (2-50 nm) or macro porous (>50 nm). Since the first report of mesoporous silica in the 1990s 3,4 , the variety of mesoporous materials available has rapidly expanded, encompassing a very broad range of compositions.Mesoporous materials have exceptional properties, including ultrahigh surface areas, large pore volumes, tunable pore sizes and shapes, and also exhibit nanoscale effects in their mesochannels and on their pore walls. These features are particularly advantageous for applications in energy conversion and storage [5][6][7][8][9][10] . In principle, high surface areas should provide a large number of reaction or interaction sites for surface or interface-related processes such as adsorption, separation, catalysis and energy storage; however, a high surface area does not necessarily translate to an improved performance in applications. Large pore volumes have shown promise in the loading of guest species and in the accommodation of the expansion and strain relaxation during repeated electrochemical energy storage processes. Uniform and tunable mesopore channels facilitate the transport of atoms, ions and large molecules through the bulk of the material, thereby increasing the number of active sites with high accessibility and overcoming the size restriction encountered with microporous materials. In addition, there are fascinating nanoconfinement effects in the voids of uniform mesochannels, which are advantageous in catalysis and energy storage. 3D nanometre-sized frameworks can produce extraordinary nanoscale effects (that is, surface and quantum effects) that result in mesoporous materials with u...

Carbon nanotubes (CNTs) are of great interest for many potential applications because of their extraordinary electronic, mechanical and structural properties. However, issues of chaotic staking, high cost and high energy dissipation in the synthesis of CNTs remain to be resolved. Here we develop a facile, general and high-yield strategy for the oriented formation of CNTs from metal-organic frameworks (MOFs) through a low-temperature (as low as 430 °C) pyrolysis process. The selected MOF crystals act as a single precursor for both nanocatalysts and carbon sources. The key to the formation of CNTs is obtaining small nanocatalysts with high activity during the pyrolysis process. This method is successfully extended to obtain various oriented CNT-assembled architectures by modulating the corresponding MOFs, which further homogeneously incorporate heteroatoms into the CNTs. Specifically, nitrogen-doped CNT-assembled hollow structures exhibit excellent performances in both energy conversion and storage. On the basis of experimental analyses and density functional theory simulations, these superior performances are attributed to synergistic effects between ideal components and multilevel structures. Additionally, the appropriate graphitic N doping and the confined metal nanoparticles in CNTs both increase the densities of states near the Fermi level and reduce the work function, hence efficiently enhancing its oxygen reduction activity. The viable synthetic strategy and proposed mechanism will stimulate the rapid development of CNTs in frontier fields.

Polymeric carbon nitride (C3N4) has emerged as the most promising candidate for metal-free photocatalysts but is plagued by low activity due to the poor quantum efficiency and low specific surface area. Exfoliation of bulk crystals into ultrathin nanosheets has proven to be an effective and widely used strategy for enabling high photocatalytic performances; however, this process is complicated, time-consuming, and costly. Here, we report a simple bottom-up method to synthesize porous few-layer C3N4, which involves molecule self-assembly into layered precursors, alcohol molecules intercalation, and subsequent thermal-induced exfoliation and polycondensation. The as-prepared few-layer C3N4 expose more active sites and greatly enhance the separation of charge carriers, thus exhibiting a 26-fold higher hydrogen evolution activity than bulk counterpart. Furthermore, we find that both the high activity and selectivity for the oxidative coupling of amines to imines can be obtained under visible light that surpass those of other metal-free photocatalysts so far.

Thiol-and amino-functionalized SBA-15 silicas with uniform mesoporosities were prepared and employed for removing heavy metal ions from waste water; the thiolated SBA-15 adsorbent exhibited a higher complexation affinity for Hg 2+ , while the other metal ions (Cu 2+ , Zn 2+ , Cr 3+ and Ni 2+ ) showed exceptional binding ability with its aminated analogue.

Functional mesoporous carbons have attracted significant scientific and technological interest owning to their fascinating and excellent properties. However, controlled synthesis of functional mesoporous carbons with large tunable pore sizes, small particle size, well-designed functionalities, and uniform morphology is still a great challenge. Herein, we report a versatile nanoemulsion assembly approach to prepare Ndoped mesoporous carbon nanospheres with high uniformity and large tunable pore sizes (5−37 nm). We show that the organic molecules (e.g., 1,3,5-trimethylbenzene, TMB) not only play an important role in the evolution of pore sizes but also significantly affect the interfacial interaction between soft templates and carbon precursors. As a result, a welldefined Pluronic F127/TMB/dopamine nanoemulsion can be facilely obtained in the ethanol/water system, which directs the polymerization of dopamine into highly uniform polymer nanospheres and their derived N-doped carbon nanospheres with diversely novel structures such as smooth, golf ball, multichambered, and dendritic nanospheres. The resultant uniform dendritic mesoporous carbon nanospheres show an ultralarge pore size (∼37 nm), small particle size (∼128 nm), high surface area (∼635 m 2 g −1 ), and abundant N content (∼6.8 wt %), which deliver high current density and excellent durability toward oxygen reduction reaction in alkaline solution.

Intricate hollow structures garner tremendous interest due to their aesthetic beauty, unique structural features, fascinating physicochemical properties, and widespread applications. Here, the recent advances in the controlled synthesis are discussed, as well as applications of intricate hollow structures with regard to energy storage and conversion. The synthetic strategies toward complex multishelled hollow structures are classified into six categories, including well-established hard- and soft-templating methods, as well as newly emerging approaches based on selective etching of "soft@hard" particles, Ostwald ripening, ion exchange, and thermally induced mass relocation. Strategies for constructing structures beyond multishelled hollow structures, such as bubble-within-bubble, tube-in-tube, and wire-in-tube structures, are also covered. Niche applications of intricate hollow structures in lithium-ion batteries, Li-S batteries, supercapacitors, Li-O batteries, dye-sensitized solar cells, photocatalysis, and fuel cells are discussed in detail. Some perspectives on the future research and development of intricate hollow structures are also provided.

This review highlights the recent progress in porous materials (MOFs, zeolites, POPs, nanoporous carbons, and mesoporous materials) for CO₂ capture and conversion.