Molecular hydrogen evolution catalysts (HECs) are synthetically tunable and often exhibit high activity, but they are also hampered by stability concerns and practical limitations associated with their use in the homogeneous phase. Their incorporation as integral linker units in metal–organic frameworks (MOFs) can remedy these shortcomings. Moreover, the extended three-dimensional structure of MOFs gives rise to high catalyst loadings per geometric surface area. Herein, we report a new MOF that exclusively consists of cobaloximes, a widely studied HEC, that act as metallo-linkers between hexanuclear zirconium clusters. When grown on conducting substrates and under applied reductive potential, the cobaloxime linkers promote electron transport through the film as well as function as molecular HECs. The obtained turnover numbers are orders of magnitude higher than those of any other comparable cobaloxime system, and the molecular integrity of the cobaloxime catalysts is maintained for at least 18 h of electrocatalysis. Being one of the very few hydrogen evolving electrocatalytic MOFs based on a redox-active metallo-linker, this work explores uncharted terrain for greater catalyst diversity and charge transport pathways.

Transformation of tetra(4-cyanophenyl)ethylene under Lewis acidic (ZnCl2) conditions at 400 °C leads to the formation of a porous covalent triazine-based organic framework (CTF) with a high surface area (2235 m(2) g(-1)), high CO2 and CH4 uptakes and the highest hydrogen uptake for a CTF material (1.86 wt% at 77 K, 1 bar).

Adamantane substituted with two to four 4-cyanophenyl groups was used for preparation of a new series of robust Porous Covalent Triazine-based Framework (PCTF) materials. Novel adamantane PCTFs were synthesized in good yields (>80%) by the trimerization reaction of 1,3-bis-, 1,3,5-tris-and 1,3,5,7tetrakis(4-cyanophenyl)adamantane, respectively, in the presence of ZnCl 2 (Lewis acid condition) and CF 3 SO 3 H (strong Brønsted acid condition). From N 2 adsorption isotherms, the Lewis acid condition gives higher surface areas than the strong Brønsted acid condition. The amorphous nano-to microporous frameworks (>50% micropore fraction) exhibit excellent thermal stabilities (>450 C) with BET surface areas up to 1180 m 2 g À1 . A very similar ultramicropore size distribution between 4 and 10 Å was derived from CO 2 adsorption isotherms with a "CO 2 on carbon based slit-pore model". At 1 bar the gases H 2 (at 77 K), CO 2 (at 273 and 293 K) and CH 4 (at 273 K) are adsorbed up to 1.24 wt%, 58 cm 3 g À1 and 20 cm 3 g À1 , respectively. Gas uptake increases with BET surface area and micropore volume which in turn increase with the number of cyano groups in the monomer. From single component adsorption isotherms, IAST-derived ideal CO 2 :N 2 , CO 2 :CH 4 and CH 4 :N 2 selectivity values of up to 41 : 1, 7 : 1 and 6 : 1, respectively, are calculated for p / 0 at 273 K. The adamantane PCTFs have isosteric heats of adsorption for CO 2 of 25-28 kJ mol À1 at zero loading and most of them also >25 kJ mol À1 over the entire adsorption range which is well above the heat of liquefaction of bulk CO 2 or the isosteric enthalpy of adsorption for CO 2 on activated carbons.

Two microporous CTFs with triptycene (TPC) and fluorene (FL) have been synthesized through a mild AlCl3-catalyzed Friedel–Crafts reaction, with the highest surface area of up to 1668 m2 g−1 for non-ionothermal CTFs. CTF-TPC and CTF-FL show an excellent carbon dioxide uptake capacity of up to 4.24 mmol g−1 at 273 K and 1 bar.