Sharp Volcano-Type Synergy and Visible Light Acceleration in H2 Release upon B2(OH)4 Hydrolysis Catalyzed by Au-Rh@Click-Dendrimer Nanozymes

Rok publikacji: 2022
Wydawca:  ACS Appl. Energy Mater., 2022, 5, 3, 3834–3844
Zobacz publikację
Q. Zhao, N. Kang, M. M. Moro, E. G. Cal, S. Moya, L. E. Coy, L. Salmon, X. Liu, D. Astruc
Hydrogen (H2) formation from hydrogen-rich precursors is a hot topic, whereby carbon-free energy perspectives, mechanistic features, and synthetic applications are actively searched. Here, we report oxygen atom uptake from water under ambient conditions, producing H2 in the presence of alloyed Au-Rh nanoparticle catalysts encapsulated in a “click”-dendrimer. These systems are named nanozymes (NZs) because their function and mechanism resemble those of hydrogenase enzymes. The Au-Rh NZs with variable proportions of Au and Rh exhibit positive sharp volcano-type synergy and visible light-induced acceleration. The best synergy in the dark is disclosed in Au4Rh1, achieving a turnover frequency (TOFs) of 5100 molH2 molcata–1 min–1 in dark, 3.4 times higher than the related Au NZ and 8.9 times higher than the related Rh NZ at 25 ± 1 °C. The catalytic activity of Au-Rh for H2 evolution is enhanced by visible light irradiation due to the Au plasmon, so that the synergistic effect in the dark and the visible light-induced rate enhancement cumulate for Au4Rh1, allowing for complete B2(OH)4 hydrolysis in 39 s at 25 ± 1 °C (TOFs = 6000 molH2 molcata–1 min–1). Upon increasing the Rh content, Au-Rh provides less synergy in the dark, whereas the light enhancement of the reaction rate increases, reaching a maximum for Au1Rh2. Experiments using D2O, including kinetic isotope effect determination, suggest that the rate-determining step of the reaction involves concerted O–H bond cleavage of water and support the proposed catalytic reaction mechanism.

Kontakt | Baza kontaktów | RSS | Login
© 2022 CENTRUM NANOBIOMEDYCZNE UAM | ul. Wszechnicy Piastowskiej 3, PL 61614 Poznań, Poland | tel.+48 61 829 67 04.