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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A series of ultrathin MoS2 nanosheet decorated ketoenamine-based COF (TpPa-1) photocatalysts show excellent photocatalytic activity under visible light irradiation without noble-metal co-catalysts.

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A COF-based Z-scheme heterostructure hybrids (α-Fe2O3/TpPa-2-COF) for noble-metal-free photocatalytic hydrogen evolution.

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This work presents a study of electrochemistry of uranium on a liquid gallium in LiCl-KCl eutectic by applying a series of electrochemical techniques. The electrochemical window of the Ga electrode in LiCl-KCl eutectic is about −1.40 to −0.35 V vs. Ag/AgCl. The reduction of U(III) on liquid gallium starts at −0.86 V and is a one step process with the transfer of three electrons. The co-reductive cyclic voltammograms of U(III) and Ga(III) present a couple of sharp redox peaks at about −0.95 and −0.84 V, corresponding to the formation and dissolution of the intermetallic compound UGa3. In addition, the reduction of Ga(III) in LiCl-KCl melt is a two-step process: Ga(III) → Ga(I) → Ga. The activity coefficient and solubility of U in liquid Ga at the temperature range from 673 to 823 K were determined by coulometric titration and open circuit potential respectively. The Gibbs free energy for the formation of UGa3 was also calculated. The intermetallic compound UGa3 was deposited by potentiostatic electrolysis at −1.0 V in the LiCl-KCl -GaCl3-UCl3 and LiCl-KCl-UCl3 melt on solid W and liquid Ga electrodes at 773 K, respectively. The electrolysis efficiency is about 97% based on the ICP result. Scanning Electron Microscopy coupled with Energy Dispersive Spectroscopy (SEM-EDS) and X-ray diffraction (XRD) characterizations further identified the formation of UGa3.