TY - JOUR

T1 - Investigation of the Photocatalytic Hydrogen Production of Semiconductor Nanocrystal-Based Hydrogels

AU - Schlenkrich, Jakob Cornelius

AU - Lübkemann-Warwas, Franziska

AU - Bigall, Nadja-Carola

A2 - Graf, Rebecca Tatjana

A2 - Wesemann, Christoph

A2 - Schoske, Larissa

A2 - Rosebrock, Marina

A2 - Hindricks, Karen Deli Josephine

A2 - Behrens, Peter

A2 - Bahnemann, Detlef

A2 - Dorfs, Dirk

N1 - Funding Information: J.S. and F.L.‐W. contributed equally to this work. This work was funded by the German Research Foundation (Deutsche Forschungsgemeinschaft, DFG) with the grant agreement BI 1708/4‐1 and under Germany's excellence strategy within the cluster of excellence PhoenixD (EXC 2122, project ID 390833453). The studies performed in the laboratory “Photoactive nanocomposite materials” were supported by Saint‐Petersburg State University (ID: 73032813). R.T.G. is thankful for financial support from the Hannover School for Nanotechnology (hsn). Moreover, the authors thank Armin Feldhoff and Jürgen Caro for providing the SEM and XRD facility, and thank the Laboratory of Nano and Quantum Engineering for access to TEM.

PY - 2023/5/24

Y1 - 2023/5/24

N2 - Destabilization of a ligand-stabilized semiconductor nanocrystal solution with an oxidizing agent can lead to a macroscopic highly porous self-supporting nanocrystal network entitled hydrogel, with good accessibility to the surface. The previously reported charge carrier delocalization beyond a single nanocrystal building block in such gels can extend the charge carrier mobility and make a photocatalytic reaction more probable. The synthesis of ligand-stabilized nanocrystals with specific physicochemical properties is possible, thanks to the advances in colloid chemistry made in the last decades. Combining the properties of these nanocrystals with the advantages of nanocrystal-based hydrogels will lead to novel materials with optimized photocatalytic properties. This work demonstrates that CdSe quantum dots, CdS nanorods, and CdSe/CdS dot-in-rod-shaped nanorods as nanocrystal-based hydrogels can exhibit a much higher hydrogen production rate compared to their ligand-stabilized nanocrystal solutions. The gel synthesis through controlled destabilization by ligand oxidation preserves the high surface-to-volume ratio, ensures the accessible surface area even in hole-trapping solutions and facilitates photocatalytic hydrogen production without a co-catalyst. Especially with such self-supporting networks of nanocrystals, the problem of colloidal (in)stability in photocatalysis is circumvented. X-ray photoelectron spectroscopy and photoelectrochemical measurements reveal the advantageous properties of the 3D networks for application in photocatalytic hydrogen production.

AB - Destabilization of a ligand-stabilized semiconductor nanocrystal solution with an oxidizing agent can lead to a macroscopic highly porous self-supporting nanocrystal network entitled hydrogel, with good accessibility to the surface. The previously reported charge carrier delocalization beyond a single nanocrystal building block in such gels can extend the charge carrier mobility and make a photocatalytic reaction more probable. The synthesis of ligand-stabilized nanocrystals with specific physicochemical properties is possible, thanks to the advances in colloid chemistry made in the last decades. Combining the properties of these nanocrystals with the advantages of nanocrystal-based hydrogels will lead to novel materials with optimized photocatalytic properties. This work demonstrates that CdSe quantum dots, CdS nanorods, and CdSe/CdS dot-in-rod-shaped nanorods as nanocrystal-based hydrogels can exhibit a much higher hydrogen production rate compared to their ligand-stabilized nanocrystal solutions. The gel synthesis through controlled destabilization by ligand oxidation preserves the high surface-to-volume ratio, ensures the accessible surface area even in hole-trapping solutions and facilitates photocatalytic hydrogen production without a co-catalyst. Especially with such self-supporting networks of nanocrystals, the problem of colloidal (in)stability in photocatalysis is circumvented. X-ray photoelectron spectroscopy and photoelectrochemical measurements reveal the advantageous properties of the 3D networks for application in photocatalytic hydrogen production.

KW - charge carrier separation

KW - nanocrystal-based hydrogels

KW - photocatalysis

KW - photocatalytic hydrogen production

KW - self-assembly

UR - http://www.scopus.com/inward/record.url?scp=85148738727&partnerID=8YFLogxK

U2 - 10.1002/smll.202208108

DO - 10.1002/smll.202208108

M3 - Article

VL - 19

JO - Small

JF - Small

SN - 1613-6810

IS - 21

M1 - 2208108

ER -