We present novel titanium-porphyrinic gels (TPGs) and titanium-porphyrinic aerogels (TPAs), in whichp orphyrinic ligand tetrakis(4-carboxyphenyl)porphyrin is coordinated to Ti-oxo clusters.T hese hierarchically porous TPAs,w ith micro-, meso-, and macropores and reactant-concentrationdependent Brunauer-Emmett-Teller surface areas of 407-738 m 2 g À1 ,are prepared by CO 2 critical point drying of TPGs. Although the Ti 4+ ! Ti 3+ photoreduction of TPAs is less efficient than that of crystalline microporous Ti-porphyrinic framework DGIST-1, prompt diffusion of O 2 and spintrapping agents into the TPApores causes the rapid generation of reactive oxygen species (ROS), as observed by EPR spectroscopy. When used as an ROS scavenger,l arge 1,3diphenylisobenzofuran is degraded by the best-performing TPA1 0t imes faster than by DGIST-1, suggesting that the accessibility of molecules (reactants) to pores (reactive centers) strongly influences photocatalytic activity.

We present novel titanium-porphyrinic gels (TPGs) and titanium-porphyrinic aerogels (TPAs), in whichp orphyrinic ligand tetrakis(4-carboxyphenyl)porphyrin is coordinated to Ti-oxo clusters.T hese hierarchically porous TPAs,w ith micro-, meso-, and macropores and reactant-concentrationdependent Brunauer-Emmett-Teller surface areas of 407-738 m 2 g À1 ,are prepared by CO 2 critical point drying of TPGs. Although the Ti 4+ ! Ti 3+ photoreduction of TPAs is less efficient than that of crystalline microporous Ti-porphyrinic framework DGIST-1, prompt diffusion of O 2 and spintrapping agents into the TPApores causes the rapid generation of reactive oxygen species (ROS), as observed by EPR spectroscopy. When used as an ROS scavenger,l arge 1,3diphenylisobenzofuran is degraded by the best-performing TPA1 0t imes faster than by DGIST-1, suggesting that the accessibility of molecules (reactants) to pores (reactive centers) strongly influences photocatalytic activity.