Recent progress in the synthesis and applications of zeolitic imidazolate framework materials is presented in this review.

Nanotube–Si heterojunction solar cells are fabricated by coating a thin film of double‐walled carbon nanotubes on n‐type silicon wafers. These solar cells show power‐conversion efficiencies in the range of 5–7%. The nanotubes perform multiple functions in the cells, including charge separation, charge transport, and charge collection.

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Molybdenum disulfide (MoS 2) has a theoretical catalytic activity comparable to Pt but in practice is a poor catalyst in bulk form due to the scarcity of metal edge sites and low electrical conductivity. Recent developments on MoS 2 monolayers (MLs) are more encouraging in developing cheap and efficient catalysts, but the majority metal atoms are on the basal plane are catalytically inactive. The rapid recombination of the electron-hole pairs and electronic band structure of the most stable 2H-MoS 2 MLs are also unsuitable for efficient photocatalysis, especially for solar-driven water splitting. Here, we show that reducing the lateral size and creating sulphur (S) vacancies of MoS 2 MLs not only increases dramatically the density of catalytically active sites, but also adjusts the band structure to become highly suitable for solar-driven catalysis. Besides, this preparation efficiently avoids fast charge recombination associated with MoS 2 , improves light harvesting, and gives a newly formed metallic state to transfer electrons for photocatalytic reactions. By way of example, we have demonstrated remarkable photocatalytic degradation of methylene blue (MB) and methylene orange (MO) dye using the S-depleted Mo-S nanocrystals (NCs, 2-25 nm). The NCs are also promising to efficiently generate hydrogen (H 2) from water with sacrificial reagents and solar light irradiation. Our study shows how careful design and modification of materials can result in highly efficient photocatalysts, which give considerable opportunities of the transition metal dichalcogenides (TMDs) beyond just MoS 2 to develop highly efficient and economic catalysts.

Optimized TiO2/CuxO/C nanocomposites derived from bi-MOF NH2-MIL-125(Ti/Cu) with in situ formed p–n heterojunctions exhibited superior photocatalytic HER performance without noble metals.

Surface-functionalized nitrogen/carbon co-doped polymorphic TiO 2 phase junction nanoparticles uniformly distributed in porous carbon matrix were synthesized by a simple one-step pyrolysis of titanium based metal-organic framework (MOF), NH 2 -MIL-125(Ti) at 700°C under water vapour atmosphere. Introducing water vapour during the pyrolysis of NH 2 -MIL-125(Ti) not only functionalizes the derived porous carbon matrix with carboxyl groups but also forms additional oxygen-rich N like interstitial/intraband states lying above the valence band of TiO 2 along with the self-doped carbon, which further narrows the energy band gaps of polymorphic TiO 2 nanoparticles that enhance photocatalytic charge transfer efficiency. Without co-catalyst, sample N-C-TiO 2 /C ArW demonstrates H 2 evolution activity of 426 mmol g cat -1 h À1 , which remarkably outperforms commercial TiO 2 (P-25) and N-C-TiO 2 /C Ar with a 5-fold and 3-fold H 2 generation, respectively. This study clearly shows that water vapour atmosphere during the pyrolysis increases the hydrophilicity of the Ti-MOF derived composites by functionalizing porous carbon matrix with carboxylic groups, as well as enhancing the electrical conductivity and charge transfer efficiency due to the formation of additional localized oxygen-rich N like interstitial/intraband states. This work also demonstrates that by optimizing the anatase-rutile phase composition of the TiO 2 polymorphs, tuning the energy band gaps by N/C co-doping and functionalizing the porous carbon matrix in the N-C-TiO 2 / C nanocomposites, the photocatalytic H 2 generation activity can be further enhanced.

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Ceramics suffer the curse of extreme brittleness and demand new design philosophies and novel concepts of manufacturing to overcome such intrinsic drawbacks, in order to take advantage of most of their excellent properties. This has been one of the foremost challenges for ceramic material experts. Tailoring the ceramics structures at nanometre level has been a leading research frontier; whilst upgrading via reinforcing ceramic matrices with nanomaterials including the latest carbon nanotubes (CNTs) and graphene has now become an eminent practice for advanced applications. Most recently, several new strategies have indeed improved the properties of the ceramics/CNT nanocomposites, such as by tuning with dopants, new dispersions routes and modified sintering methods. The utilisation of graphene in ceramic nanocomposites, either as a solo reinforcement or as a hybrid with CNTs, is the newest development. This article will summarise the recent advances, key difficulties and potential applications of the ceramics nanocomposites reinforced with CNTs and graphene.