Optimizing electron transfer from CdSe QDs to hydrogenase for photocatalytic H₂ production

Abstract

A series of viologen related redox mediators of varying reduction potential has been characterized and their utility as electron shuttles between CdSe quantum dots and hydrogenase enzyme has been demonstrated.

Covalent Organic Frameworks Enabling Site Isolation of Viologen‐Derived Electron‐Transfer Mediators for Stable Photocatalytic Hydrogen Evolution

“…As shown in Scheme 1, a typical β‐ketoenamine linked COF is constructed using 2,2′‐bipyridine as the strut, which is then quaternized with dibromo alkanes into cyclic diquats, that is, BPy 2+ . The resulting COF constitutes an integrative platform containing 2,2′‐bipyridine as a photosensitizer and cyclic diquat as an ETM [31] for photocatalytic water splitting. Despite the coaxial stacking of COF layers, the cationic diquats are likely to be positioned at the different individual layers due to strong electrostatic repulsion.…”

“…Herein, we propose ac onveniently accessible method to engineer the site-isolated ETM modules on a2,2'-bipyridinebased COF by apost-synthetic route.Asshown in Scheme 1, atypical b-ketoenamine linked COF is constructed using 2,2'bipyridine as the strut, which is then quaternized with dibromo alkanes into cyclic diquats,t hat is,B Py 2+ .T he resulting COF constitutes an integrative platform containing 2,2'-bipyridine as ap hotosensitizer and cyclic diquat as an ETM [31] for photocatalytic water splitting.Despite the coaxial stacking of COF layers,t he cationic diquats are likely to be positioned at the different individual layers due to strong electrostatic repulsion. Meanwhile,t he purposeful incorporation of different alkyl chains from -(CH 2 ) 2 -t o-(CH 2 ) 4 -o n the cyclic diquats further generates the steric hindrance to distance the species apart.…”

Photo‐Electrochemical Device Enabling Luminescence Switching of LaPO4:Ce,Tb Nanoparticle Layers

“…To avoid this problem, small organic molecules are utilized as redox shuttles to mediate electron transfer between the LaPO 4 :Ce,Tb nanoparticles and the current collector. Redox shuttles are commonly used as enhancing additives in fields such as biotechnology, [ 17,18 ] photocatalysis, [ 19–21 ] or batteries. [ 22–25 ] The redox shuttles are added to the electrolyte and diffuse throughout the nanoporous nanoparticle film enabling repetitive luminescence on/off switching based on the applied potential.…”

Spectroscopic investigations under whole cell conditions provide new insight into the metal hydride chemistry of [FeFe]-hydrogenase

“…28 The exact nature of these intermediate states and their relevance to the catalytic mechanism is under debate. 10,27,[30][31][32][33] However, all recent models agree that a terminal hydride is formed during catalysis. One such intermediate, denoted H hyd , has been detected in vitro and shown to accumulate in amino acid variants with disrupted proton transfer networks, but also in the native enzyme under reducing conditions at low pH.…”