Crystalline and porous covalent organic frameworks (COFs) and metal-organic frameworks (MOFs) materials have attracted enormous attention in the field of photocatalytic H evolution due to their long-range order structures, large surface areas, outstanding visible light absorbance, and tunable band gaps. In this work, we successfully integrated two-dimensional (2D) COF with stable MOF. By covalently anchoring NH -UiO-66 onto the surface of TpPa-1-COF, a new type of MOF/COF hybrid materials with high surface area, porous framework, and high crystallinity was synthesized. The resulting hierarchical porous hybrid materials show efficient photocatalytic H evolution under visible light irradiation. Especially, NH -UiO-66/TpPa-1-COF (4:6) exhibits the maximum photocatalytic H evolution rate of 23.41 mmol g h (with the TOF of 402.36 h ), which is approximately 20 times higher than that of the parent TpPa-1-COF and the best performance photocatalyst for H evolution among various MOF- and COF-based photocatalysts.

Covalent-organic frameworks (COFs) have been recognized as a new type of promising photocatalysts for hydrogen evolution. To investigate how different functional groups attached in the backbone of COFs affect the overall photocatalytic H 2 evolution, for the first time, we selected and synthesized a series of ketoenamine-based COFs with the same host framework as model system. It includes TpPaÀ COFÀ X (X =À H, À (CH 3 ) 2 , and À NO 2 ) with three different groups attached in the backbone of TpPaÀ COF. We systematically investigated the differences in morphology, light-absorption intensity and band gap of these 2D COFs. The results of photocatalytic H 2 evolution measurements indicate that the TpPaÀ COFÀ (CH 3 ) 2 shows the best activity, while the activity of TpPaÀ COFÀ NO 2 is relatively low compared to that of other two COFs in the system. Moreover, the separation ability of photogenerated charge was also followed the order of TpPaÀ COFÀ (CH 3 ) 2 > TpPaÀ COF > TpPaÀ COFÀ NO 2 . The best photocatalytic H 2 production performance of TpPaÀ COFÀ (CH 3 ) 2 in these systems should be mainly attributed to the better electron-donating ability of À CH 3 groups compared to À H or À NO 2 group, which result in more efficient charge transferring in the inner of the material. This work demonstrates that reasonably adding electrondonating group in TpPaÀ COFs can lead to a better photocatalytic H 2 evolution activity, and which is meaningful for further design of efficient COF-based photocatalysts for H 2 evolution.[a] J.

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Nanoscale metal-organic frameworks (NMOFs) have proven to be a class of promising drug carriers as a result of their high porosity, crystalline nature with definite structure information, and potential for further functionality. However, MOF-based drug carriers with active tumor-targeting function have not been extensively researched until now. Here we show a strategy for constructing active tumor-targeted NMOF drug carriers by anchoring functional folic acid (FA) molecules onto the metal clusters of NMOFs. Two zirconium-based MOFs, MOF-808 and NH -UiO-66, were chosen as models to reduce to the nanoscale for application as drug carriers, and then the terminal carboxylates of FA molecules were coordinated to Zr clusters on the surfaces of the nanoparticles by substitution of the original formate or terminal -OH ligands. The successful modification with FA was confirmed by solid-state C MAS NMR and UV/Vis spectroscopy and other characterization methods. Drug loading and controlled release behavior at different pH were determined by utilizing the anticancer drug 5-fluorouracil (5-FU) as the model drug. Confocal laser scanning microscopy measurements further demonstrated that 5-FU-loaded FA-NMOFs have excellent targeting ability through the efficient cellular uptake of FA-NMOFs. This work opens up a new avenue to the construction of active tumor-targeted NMOF-based drug carriers with potential for cancer therapies.

Carbon nanodots (CDs) have attracted enormous attention in the photocatalytic area for their high light-harvesting and outstanding electron transfer abilities. In this work, NH2–UiO-66 was first composited with g-C3N4 to construct an NH2–UiO-66/g-C3N4 heterojunction. Then, CDs were incorporated into the pores of NH2–UiO-66 by the pore space of the framework serving as confined nanoreactors to construct a CD@NH2–UiO-66/g-C3N4 ternary composite. The ultrasmall CDs transformed from incapsulated glucose in the pores of NH2–UiO-66 were uniformally distributed in MOFs and extensively improve the photocatalytic hydrogen evolution activity of the composite under visible-light irradiation. The optimum photocatalytic H2 evolution rate of the CD@NH2–UiO-66/g-C3N4 composite with a CD content of 2.77 wt % is 2.930 mmol·h–1·g–1 under visible-light irradiation, which is 32.4, 38.6, and 17.5 times as high as that of bulk g-C3N4, NH2–UiO-66, and NH2–UiO-66/g-C3N4, respectively. The remarkable enhancement of the photocatalytic activity should be that CDs as cocatalysts effectively increase the transport properties of electrons and efficient charge separation. Moreover, CD@NH–UiO-66/g-C3N4 nanocomposites showed excellent stability during the photocatalytic process as determined by XRD and TEM analyses for the sample after reaction. The results of the mechanism investigation reveal that CDs in the ternary composite serve as electron transfer mediation to facilitate charge separation, enhancing light absorption and extending the lifetime of photoinduced carriers. The present work shows that encapsulating CDs into the pores of MOFs is an efficient strategy to improve the activity of an MOF-based photocatalyst.