Strong synergy between gold nanoparticles and cobalt porphyrin induces highly efficient photocatalytic hydrogen evolution

Abstract

The reaction efficiency of reactants near plasmonic nanostructures can be enhanced significantly because of plasmonic effects. Herein, we propose that the catalytic activity of molecular catalysts near plasmonic nanostructures may also be enhanced dramatically. Based on this proposal, we develop a highly efficient and stable photocatalytic system for the hydrogen evolution reaction (HER) by compositing a molecular catalyst of cobalt porphyrin together with plasmonic gold nanoparticles, around which plasmonic effects of localized electromagnetic field, local heating, and enhanced hot carrier excitation exist. After optimization, the HER rate and turn-over frequency (TOF) reach 3.21 mol g−1 h−1 and 4650 h−1, respectively. In addition, the catalytic system remains stable after 45-hour catalytic cycles, and the system is catalytically stable after being illuminated for two weeks. The enhanced reaction efficiency is attributed to the excitation of localized surface plasmon resonance, particularly plasmon-generated hot carriers. These findings may pave a new and convenient way for developing plasmon-based photocatalysts with high efficiency and stability.

Hot-Electron-Driven Interfacial Chemistry Using Non-Noble Plasmonic Cu under Visible-Light Irradiation

“…Visible-light-driven photocatalysis has been a very promising strategy for solar-to-chemical energy conversion. , To improve the light-to-energy conversion efficiency in visible-light photocatalysis, extensive efforts are applied to design and develop new heterogeneous photocatalysts. − Plasmonic metal nanoparticles (NPs) as emerging heterogeneous photocatalysts have aroused considerable interest , because of their large absorption cross sections in the visible region. As their most prominent feature, the metallic NPs have strong interactions with visible light to generate coherent oscillations of free electrons within the NPs, which is called localized surface plasmon resonance (LSPR). , Via a nonradiative decay channel, excited surface plasmons in the metallic NPs would decay into energetic hot carriers (electron–hole pairs), where the high energy electrons are above the Fermi Level, while the hot holes are below it.…”

Excited-State Energy Transfer-Associated Dual Emission of Light-Emitting Polymers Containing Sulfonated Graphene Oxide for Sensing of pH, Co(II), and Bi(III)

“…Notably, in dilute solutions within 50–100 μg mL –1 , absorption peak was found at 349 nm, whereas an additional broad peak within 393–408 nm was noticed above 100 μg mL –1 , confirming the formation of HLEP3 -aggregate at the higher concentration (Figure a) . The coexistence of both HLEP3 and HLEP3 -aggregate in GS was further confirmed from different distributions of particle size in FESEM photomicrographs of HLEP3 (Figure b) and the appearance of two distribution maxima at 342 and 655 nm in DLS measurement of 200 μg mL –1 HLEP3 /DMSO solution (Figure c) . Here, a flower-like HLEP3 -aggregate with folded, wrinkled, and exfoliated SGO nanoparticle was evident from FESEM photomicrographs of HLEP3 (Figure b) .…”

“…Notably, the red shifting of LEP5 -aggregate peak compared to that of LEP5 could be correlated to the extended conjugation of electrons involving different functional groups . Thus, the coexistence of LEP5 and LEP5 -aggregate could be supported by the appearance of a UV peak at 274 nm having a broad tail within 326–353 nm (Figure S7a), broad distribution of particle size with maximum at 295 nm in dynamic light scattering (DLS) measurement (Figure S7f), and field emission scanning electron microscopy (FESEM) photomicrographs (Figure S7g). …”

“…44 The coexistence of both HLEP3 and HLEP3-aggregate in GS was further confirmed from different distributions of particle size in FESEM photomicrographs of HLEP3 (Figure 4b) and the appearance of two distribution maxima at 342 and 655 nm in DLS measurement of 200 μg mL −1 HLEP3/DMSO solution (Figure 4c). 45 Here, a flower-like HLEP3-aggregate with folded, wrinkled, and exfoliated SGO nanoparticle was evident from FESEM photomicrographs of HLEP3 (Figure 4b). 47 Notably, the difference in surface morphologies of LEP5/LEP5aggregate (Figure S7g) and HLEP3/HLEP3-aggregate (Figure 4b) along with the shifting of absorption peaks from 274 and 326−353 nm in LEP5 to 349 and 393−408 nm in HLEP3, respectively, indicated the grafting of SGO in LEP5 (Figure S7a).…”

“…(Figure 4c) along with the UV−vis peaks within 393−408 nm and at 349 nm (Figure S7a). 45,46 At λ ex1 , the local emission maximum at λ em1 originated from HLEP3 (ES) (Scheme 2b1). 44,50 Here, the excitation spectrum of emission at λ em1 showed an intense peak at 413 nm (Figure 4f).…”