Surface functionalized N-C-TiO_(2)/C nanocomposites derived from metal-organic framework in water vapour for enhanced photocatalytic H generation

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^(-1)25(Ti) at 700℃ under water vapour atmosphere.Introducing water vapour during the pyrolysis of NH_(2)-MIL^(-1)25(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 TiO2 along with the self-doped carbo n,which further narrows the energy band gaps of polymorphic TiO2 nanoparticles that enhance photocatalytic charge transfer efficiency.Without co-catalyst,sample N-C-TiO2/CArW demonstrates H_(2) evolution activity of 426 μmol gcat-1h^(-1),which remarkably outperforms commercial TiO_(2)(P-25) and N-C-TiO_(2)/CAr 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 TiO2 polymorphs,tuning the energy band gaps by N/C co-doping and functionalizing the porous carbon matrix in the N-C-TiO2/C nanocomposites,the photocatalytic H_(2) generation activity can be further enhanced.

A Golden Touch in the Design of Multifunctional Porphyrin Metallacages:Host-Guest Chemistry for Drug-Target Interactions

The use of three-dimensional self-assembled metallacages(MCgs)as multimodal drug platforms holds great promise.However,the synthesis of MCgs with increased complexity and functionality is a great challenge since understanding of the interaction of MCgs with biological targets is still limited.In this context,this work reports on the integration of a gold(III)porphyrin scaffold into a prismatic MCg structure and explores its application for multimodal therapy of cancer in vitro,namely enabling both photodynamic therapy and chemotherapy.Combining experimental approaches with a state-of-the-art metadynamics theoretical study,we discovered that the gold cage shows unprecedented host-guest interaction-driven selective stabilization of guanine-quadruplex(G4)structures-validated anticancer drug targets-disclosing a new mechanism to pursue in the design of supramolecular drugs.

Metal-organic framework derived multi-functionalized and co-doped TiO_(2)/C nanocomposites for excellent visible-light photocatalysis

Multi-functionalized and co-doped TiO_(2)/C nanocomposites were derived from the pyrolysis of Ti-MOFs at 800℃under different gaseous atmospheres and their photocatalytic performance were investigated.The gaseous atmosphere during pyrolysis plays a critical role in determining the structural,textural,optical and physicochemical properties of the derived TiO_(2)/C composites due to the synergistic effect of nitrogen-containing species,carboxylate and sulfur functionalized porous carbon as well as N/S co-doped TiO_(2)nanoparticles.All the Ti-MOFs derived TiO_(2)/C composites exclusively possess homogeneously distributed TiO_(2)nanoparticles in a functionalized disc-like porous carbon matrix and demonstrate much enhanced adsorption and photodegradation performance than commercial TiO_(2)under the same conditions.The adsorption of methylene blue(MB)in dark on these TiO_(2)/C composites are dominated with pseudo second-order kinetic model and the high adsorption capacity of MB in dark on composite TiO_(2)/C derived from MIL-125(Ti)in argon is due to its high surface area with predominant mesoporous carbon matrix in the composite.The composite N-O-TiO_(2)/C derived from NH2-MIL-125(Ti)in water vapor exhibited the highest photodegradation activity with 99.7%MB removal in 3 h under visible light due to the optimal anatase/rutile phasejunction,together with the formation of photoactive oxygen-rich N-O like interstitial/intraband states above the valence band of TiO_(2),as well as the presence of N-containing species and-OH/-COOH multi-functional groups with superhydrophilic nature of the composite.This simple one-step and easily modifiable approach can be further employed to modulate homogeneously dispersed multi-functionalized and co-doped metal oxide/carbon nanocomposites for various environment and energy-related applications.