Abstract
This paper describes a photocatalytic hydrogen evolution system that is dynamically and reversibly responsive to the pH of the surrounding solution through the actuation of a microhydrogel (microgel) matrix that hosts the photocatalysts (CdSe/CdS nanorods). The reversible actuation occurs within 0.58 (swelling) and 1.7 s (contraction). ΔpH = 0.01 relative to the pKa of the tertiary amine on the microgel polymer (7.27) results in a reversible change in the average diameter of the microgel hosts by a factor of 2.4 and a change in the photocatalytic turnover frequency (TOF) by a factor of 5. Kinetic isotope effect and photoluminescence quenching experiments reveal that the scavenging of the photoexcited hole by sulfite ions is the rate-limiting step and leads to the observed response of the TOF to pH through the actuation of the microgel.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 12135-12141 |
| Number of pages | 7 |
| Journal | Journal of Physical Chemistry Letters |
| Volume | 12 |
| Issue number | 50 |
| DOIs | |
| State | Published - Dec 23 2021 |
Funding
This work was supported as part of the Center for Bio-Inspired Energy Science (CBES), an Energy Frontier Research Center (EFRC) funded by the US Department of Energy, Office of Science, Basic Energy Sciences under Award DE-SC0000989. This work made use of the Keck-II facility of Northwestern University’s NUANCE Center, which has received support from the SHyNE Resource (NSF ECCS-2025633), the IIN, and Northwestern’s MRSEC program (NSF DMR-1720139). TEM was performed in the EPIC facility of Northwestern University’s NUANCE Center, which has received support from the Soft and Hybrid Nanotechnology Experimental (SHyNE) Resource (no. NSF ECCS-1542205), the MRSEC program (no. NSF DMR-1720139) at the Materials Research Center, the International Institute for Nanotechnology (IIN), the Keck Foundation, and the State of Illinois through the IIN. Photocatalysis experiments were performed at the REACT Core facility, which acknowledges funding from the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Catalysis Science program (DE-SC0001329 and DE-FG02-03ER15457). TGA measurements occurred in the IMSERC X-RAY facility at Northwestern University, which has received support from the Soft and Hybrid Nanotechnology Experimental (SHyNE) Resource (NSF ECCS-2025633),and Northwestern University. The authors gratefully acknowledge Dr. Christos Malliakas for his assistance with TGA and Dr. Hiroaki Sai for his assistance with GPC.
ASJC Scopus subject areas
- General Materials Science
- Physical and Theoretical Chemistry