A novel synthesis of highly active and highly stable non-noble-nickel-modified persulfated Al_(2)O_(3)@ZrO_(2) core-shell catalysts for n-pentane isomerization

The non-noble metal modified sulfated zirconia was found easy to deactivate.Herein,highly active and highly stable non-noble core-shell Ni-S_(2)O_(8)^(2−)/Al_(2)O_(3)@ZrO_(2) catalysts(Ni-SA@Z-x,x=Al content in wt%)have been successfully prepared and investigated for n-pentane isomerization.The results showed that the core-shell Ni-SA@Z-30 provided a sustained high isopentane yield(63.1%)with little or no deactivation within 5000 min at a mild reaction pressure of 2.0 MPa,which can be attributed to the following factors:(i)carbon deposition was greatly suppressed by the large pore size and huge pore volume;(ii)the loss of sulfur entities was suppressed because the small and highly dispersed tetragonal ZrO_(2) particles can bond with the S species strongly;(iii)strong Brønsted acidity can be maintained well after the isomerization.The pore structures and acid nature of the core-shell Ni-SA@Z-x are entirely different from those of the normal structure Ni-S_(2)O_(8)^(2−)/ZrO_(2)-Al_(2)O_(3),even though the Al content and the compositions of the individual components are the same.The Al_(2)O_(3)cores endow the catalysts with high internal surface area and high mechanical strength.Meanwhile,the ZrO_(2) shell,which consists of more and smaller tetragonal ZrO_(2) particles because of the large surface area of the Al_(2)O_(3)core,promotes the formation of more stable sulfur species and stronger binding sites.

Rational design of imine-linked three-dimensional mesoporous covalent organic frameworks with bor topology

Three-dimensional(3D)covalent organic frameworks(COFs)possess great potential applications in various fields.Constructing 3D COFs with large pore sizes is extremely challenging due to the interpenetration and collapse.Herein,we report a series of crystalline imine-linked 3D COFs(3D-bor-COF-1,3D-borCOF-2,3D-bor-COF-3)with mesoporous channels through rationally designing the topology configuration.These 3D-bor-COFs display permanent porosity and Brunauer–Emmett–Teller(BET)surfaces of 3205.5,1752.7,and 2077.3 m2 g−1(SLangmuir=4277.7,2480.3,and 2698.0 m2 g−1),respectively.The pore sizes of 3Dbor-COFs were confirmed by the lattice fringes from high-resolution transmission electron microscopy,as well as structural simulation and nitrogen adsorption isotherm analysis.3D-bor-COFs display large pore sizes(3.8 nm for 3D-borCOF-3),which is among the highest record of 3D COFs.Owing to the unstackedaromatic pore environment and high specific surface area,3D-bor-COFs display excellent adsorption capacity for benzene vapor(1203.9 mg g−1 for 3D-bor-COF-3)under 298 K,which is three times higher than that of the best-reported 2D COF.This work not only provides inspiration for designing 3D mesoporous imineCOFs,but also demonstrates a strategy for constructing aromatics adsorption materials.