TY - JOUR

T1 - Aggregation‐induced improvement of catalytic activity by inner‐aggregate electronic communication of metal‐fullerene‐based surfactants

AU - Kunkel, Marius

AU - Bitter, Stefan

AU - Sailer, Frank

AU - Winter, Rainer F.

AU - Polarz, Sebastian

N1 - Funding information: The current research was funded by an ERC consolidator grant (I?SURF; project 614606). We further thank Stephan Siroky for his support.

PY - 2020/5/20

Y1 - 2020/5/20

N2 - A paradigm for active constituents in (homogeneous) catalysis is that optimum performance requires maximum dispersion. Generally, aggregation results in a decline. This is a different case in supramolecular catalysis. A new concept based on surfactants equipped with functional heads is presented, which becomes a more active catalyst itself upon aggregation. The head group of the surfactants is composed of a diethylenetriamine-functionalized fullerene capable of coordinating to catalytically active metals like Co II. The improvement of catalytic properties upon aggregation is demonstrated via electrocatalytic water-splitting reaction as a model system. Detailed electrochemistry studies were performed at concentrations below and above the critical aggregation concentration (cac). While isolated surfactant molecules represent only moderately active catalysts, drastic improvement of efficiency in the hydrogen evolution (HER) as well as in the oxygen evolution reactions (OER) were detected, once vesicular structures have formed. Self-organization of the surfactants leads to an increase in turnover frequencies of up to 1300 % (HER). The strongly beneficial effect of aggregation arises from the favorable alignment of individual molecules, thus, facilitating intermolecular charge transfer processes in the vesicles.

AB - A paradigm for active constituents in (homogeneous) catalysis is that optimum performance requires maximum dispersion. Generally, aggregation results in a decline. This is a different case in supramolecular catalysis. A new concept based on surfactants equipped with functional heads is presented, which becomes a more active catalyst itself upon aggregation. The head group of the surfactants is composed of a diethylenetriamine-functionalized fullerene capable of coordinating to catalytically active metals like Co II. The improvement of catalytic properties upon aggregation is demonstrated via electrocatalytic water-splitting reaction as a model system. Detailed electrochemistry studies were performed at concentrations below and above the critical aggregation concentration (cac). While isolated surfactant molecules represent only moderately active catalysts, drastic improvement of efficiency in the hydrogen evolution (HER) as well as in the oxygen evolution reactions (OER) were detected, once vesicular structures have formed. Self-organization of the surfactants leads to an increase in turnover frequencies of up to 1300 % (HER). The strongly beneficial effect of aggregation arises from the favorable alignment of individual molecules, thus, facilitating intermolecular charge transfer processes in the vesicles.

KW - catalysis

KW - Fullerene

KW - self-assembly

KW - supramolecular chemistry

KW - surfactant

KW - water splitting

UR - http://www.scopus.com/inward/record.url?scp=85082947744&partnerID=8YFLogxK

U2 - 10.1002/cctc.202000412

DO - 10.1002/cctc.202000412

M3 - Article

VL - 12

SP - 2726

EP - 2731

JO - CHEMCATCHEM

JF - CHEMCATCHEM

SN - 1867-3880

IS - 10

ER -