Microemulsion-Assisted Self-Assembly and Synthesis of Size-Controlled Porphyrin Nanocrystals with Enhanced Photocatalytic Hydrogen Evolution

Abstract

Design and engineering of highly efficient light-harvesting nanomaterial systems to emulate natural photosynthesis for maximizing energy conversion have stimulated extensive efforts. Here we present a new class of photoactive semiconductor nanocrystals that exhibit high-efficiency energy transfer for enhanced photocatalytic hydrogen production under visible light. These nanocrystals are formed through noncovalent self-assembly of In­(III) meso-tetraphenylporphine chloride (InTPP) during microemulsion assisted nucleation and growth process. Through kinetic control, a series of uniform nanorods with controlled aspect ratio and high crystallinity have been fabricated. Self-assembly of InTPP porphyrins results in extensive optical coupling and broader coverage of the visible spectrum for efficient light harvesting. As a result, these nanocrystals display excellent photocatalytic hydrogen production and photostability under the visible light in comparison with the commercial InTPP porphyrin powders.

Hierarchical Self‐Assembly of Tetrakis(1‐pyrenyl)porphyrins into Microscopic Petals and Flowers with Ultrasensitive Room‐Temperature NO2 Sensing in a Broad Humidity Range

“…It was reported that the bottom of the lowest unoccupied molecular orbital (LUMO) in many n‐type semiconductors is approximately equal to the flat band potential . The energy band gap of the assemblies 1 and 2 were determined by Tauc plots with the estimated value of 1.82 and 1.96 eV, respectively, Figure , which are match well those of porphyrin‐based nanorods reported previously . Therefore, the highest occupied molecular orbital (HOMO) can be estimated as 1.47 and 1.60 V versus NHE.…”

Supramolecular Zinc Porphyrin Photocatalyst with Strong Reduction Ability and Robust Built‐In Electric Field for Highly Efficient Hydrogen Production

“…The reported research includes meso‐tetrakis (4‐sulfonatophenyl)‐porphyrin cobalt (CoTPPS) homogeneous hydrogen production, [ 44 ] meso‐tetra(4‐pyridyl) porphine zinc (ZnTPyP) assembly, [ 45 ] and In(III) meso‐tetraphenylporphine chloride (InTPP) nanorods. [ 46 ] More importantly, the essential mechanism about how metal centers regulate supramolecular porphyrin photocatalysts to realize high performance is still rarely reported.…”

“…The reported research includes meso-tetrakis (4-sulfonatophenyl)-porphyrin cobalt (CoTPPS) homogeneous hydrogen production, [44] mesotetra(4-pyridyl) porphine zinc (ZnTPyP) assembly, [45] and In(III) meso-tetraphenylporphine chloride (InTPP) nanorods. [46] More importantly, the essential mechanism about how metal centers regulate supramolecular porphyrin photocatalysts to realize high performance is still rarely reported.Here, we focus on fabricating a metalloporphyrin-based supramolecular host photocatalyst through regulating band structure and separation abilities of photogenerated carriers for high efficiency photocatalytic activity. The meso-tetrakis (4-carboxyphenyl) porphyrin (TCPP) is chosen as the basic building block, because the carboxyl group is an extensively studied substituent with a strong electron-withdrawing effect in porphyrin-based photocatalysts and the TCPP self-assembly shows good photocatalytic performance.…”

Tuning the Supramolecular Structures of Metal-Free Porphyrin via Surfactant Assisted Self-Assembly to Enhance Photocatalytic Performance

“…For some organic aggregates, HOMO and LUMO of π-stacked molecules were overlapped and formed electronic energy level-like structures with conduction bands (CB) and valence bands (VB). Herein, the Mott-Schottky plots of CTAB-TCPP aggregates and EG-TCPP aggregates were used to determine the electronic energy levels and the results are shown in Figures S3 and S4 [37,38]. The flat band potential (Efb) for CTAB-TCPP aggregates and EG-TCPP aggregates were−1.04 eV and −0.76 eV (vs. SCE), respectively.…”