Electrochemical water splitting is a clean technology that can store the intermittent renewable wind and solar energy in H2 fuels. However, large-scale H2 production is greatly hindered by the sluggish oxygen evolution reaction (OER) kinetics at the anode of a water electrolyzer. Although many OER electrocatalysts have been developed to negotiate this difficult reaction, substantial progresses in the design of cheap, robust, and efficient catalysts are still required and have been considered a huge challenge. Herein, we report the simple synthesis and use of α-Ni(OH)2 nanocrystals as a remarkably active and stable OER catalyst in alkaline media. We found the highly nanostructured α-Ni(OH)2 catalyst afforded a current density of 10 mA cm(-2) at a small overpotential of a mere 0.331 V and a small Tafel slope of ~42 mV/decade, comparing favorably with the state-of-the-art RuO2 catalyst. This α-Ni(OH)2 catalyst also presents outstanding durability under harsh OER cycling conditions, and its stability is much better than that of RuO2. Additionally, by comparing the performance of α-Ni(OH)2 with two kinds of β-Ni(OH)2, all synthesized in the same system, we experimentally demonstrate that α-Ni(OH)2 effects more efficient OER catalysis. These results suggest the possibility for the development of effective and robust OER electrocatalysts by using cheap and easily prepared α-Ni(OH)2 to replace the expensive commercial catalysts such as RuO2 or IrO2.

Three-dimensional porous crystalline polyimide covalent organic frameworks (termed PI-COFs) have been synthesized. These PI-COFs feature non- or interpenetrated structures that can be obtained by choosing tetrahedral building units of different sizes. Both PI-COFs show high thermal stability (>450 °C) and surface area (up to 2403 m(2) g(-1)). They also show high loading and good release control for drug delivery applications.

Covalent organic frameworks (COFs) are an emerging class of porous crystalline polymers with a wide variety of applications. They are currently synthesized through only a few chemical reactions, limiting the access and exploitation of new structures and properties. Here we report that the imidization reaction can be used to prepare a series of polyimide (PI) COFs with pore size as large as 42 × 53 Å(2), which is among the largest reported to date, and surface area as high as 2,346 m(2) g(-1), which exceeds that of all amorphous porous PIs and is among the highest reported for two-dimensional COFs. These PI COFs are thermally stable up to 530 °C. We also assemble a large dye molecule into a COF that shows sensitive temperature-dependent luminescent properties.

Easy cell: The new polymeric ionomer TPQPOH with a tris(2,4,6‐trimethoxyphenyl)phosphonium unit has excellent solubility in some low‐boiling‐point water‐soluble solvents, high ionic conductivity, and outstanding alkaline stability. A hydroxide exchange membrane fuel cell containing this ionomer exhibits increased peak power density and reduced internal resistance.

PERSPECTIVE This journal isAs a family member of redox-flow batteries (RFBs), nonaqueous RFBs can offer wide working temperature, high cell voltage, and potentially high energy density. These key features make nonaqueous RFBs an important complement of aqueous RFBs, broadening the spectrum of RFB applications. The development of nonaqueous RFBs is still at its early research stage and great challenges remain to be addressed before successful for practical applications. As such, it is essential to understand the major components in order to advance the nonaqueous RFB technology. In this perspective, three key major components of nonaqueous RFBs: organic solvent, supporting electrolyte, and redox pairs are selectively focused and discussed, with the emphases on providing an overview for those components and on highlighting the relationship between structure and property. Urgent challenges are also discussed. To advance nonaqueous RFBs, the understanding of both components and systems is critically needed and it calls for inter-disciplinary collaborations across expertise including electrochemistry, organic chemistry, physical chemistry, cell design, and system engineering. In order to demonstrate key features of nonaqueous RFBs, herein we also present an example of designing a 4.5 V ultrahigh-voltage nonaqueous RFB by combining BP/BP• − redox pair and ONF• + /OFN redox pair. PERSPECTIVEThis journal is less negative charge. When ions that do not follow those assumptions are used, the working principles are still applicable with minor alterations. (Reproduced with permission from Ref. 22) Figure 3. The BP-OFN nonaqueous RFB concept and its working principles. The negative electrolyte containing the BP/BP•redox pair and the positive electrolyte containing the OFN• + /OFN redox pair are separated by a Li + -conducting ceramic membrane (e.g., LiSICON). 1 M LiPF 6 is used as an example of supporting electrolyte. When the cell is being charged, BP molecules are reduced to form BP•radical anions in negative electrolyte (i.e., BP + e -= BP• -), and OFN molecules are oxidized to form OFN• + radical cations in positive electrolyte (i.e., OFN = OFN• + + e -). Meanwhile, Li + ions pass through Li + -conducting ceramic membrane from positive electrolyte to negative electrolyte. The discharging process is in reverse.

The design and synthesis of 3D covalent organic frameworks (COFs) have been considered a challenge, and the demonstrated applications of 3D COFs have so far been limited to gas adsorption. Herein we describe the design and synthesis of two new 3D microporous base-functionalized COFs, termed BF-COF-1 and BF-COF-2, by the use of a tetrahedral alkyl amine, 1,3,5,7-tetraaminoadamantane (TAA), combined with 1,3,5-triformylbenzene (TFB) or triformylphloroglucinol (TFP). As catalysts, both BF-COFs showed remarkable conversion (96% for BF-COF-1 and 98% for BF-COF-2), high size selectivity, and good recyclability in base-catalyzed Knoevenagel condensation reactions. This study suggests that porous functionalized 3D COFs could be a promising new class of shape-selective catalysts.

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A simple self-crosslinking strategy, without the needs of a separate crosslinker or a catalyst, is reported here. The crosslinking drastically lowers the water swelling ratio (e.g., 5-10 folds reduction) and provides excellent solvent-resistance. The self-crosslinked membrane (DCL: 5.3%) shows the highest IEC-normalized hydroxide conductivity among all crosslinked HEMs reported.