Photocatalytic H₂ production under visible-light irradiation based on covalent attachment of manganese phthalocyanine to graphene

Abstract

In this paper, a manganese phthalocyanine (MnPc) covalently functionalized graphene nanohybrid (MnPcG) has been successfully synthesized via 1,3-dipolar cycloaddition, and used as a photocatalyst after modifying it with platinum nanoparticles via photodeposition. The nanocomposite was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and UV-vis, Fourier transform infrared (FTIR), and Raman spectroscopy. These characterization results confirmed the grafting of MnPc moiety onto the graphene sheets. The intermolecular electron transfer was facilitated and the photoexcited charges recombination was suppressed as confirmed by the fluorescence quenching and enhanced photocurrent density in MnPcG nanohybrid. In comparison to graphene, the MnPcG nanohybrid shows a substantial improvement in the photocatalytic hydrogen evolution. The yields of hydrogen production of MnPcG/Pt reached to 8.59 and 1.45 mmol mg À1 under 10 h of UV-vis and visible light (l > 400 nm) irradiation, respectively. This work demonstrates that metallophthalocyanines covalently functionalized graphene is a novel photocatalyst for solar energy conversion to produce hydrogen from water. 416 978 4526; Tel: +1 416 978 4526 † Electronic supplementary information (ESI) available: XPS spectra of MnPcG, standard curve of UV-vis absorbance of MnPcCl and hydrogen production by MnPcG in the presence or absence of surfactant. See Scheme 1 The synthetic process of MnPcG. J. Mater. Chem. A This journal is

A Novel CoO1.6C0.7 Nanocomposite with Enhanced Photocatalytic Activity and Stability for Hydrogen Evolution Achieved by Carbon Dots

“…For the FTIR spectrum of CoO 1.6 C 0.7 (red line), the broad peak centred at 3445 cm −1 suggests the stretching vibrations of the surface adsorbed H 2 O . The FTIR spectrum of CoO 1.6 C 0.7 contains several strong major bands between 500 cm −1 and 1650 cm −1 , and the characteristic peaks located around 1030, 1390 and 1637 cm −1 are corresponding to the typical stretching vibration of C−O‐C, ‐COO and C=C/C=O, respectively ,. The characteristic peak centred at around 665 cm −1 belongs to the vibrations of the Co−O bond The FTIR spectra of disordered CoO 1.6 C 0.7 and CDs fit well, excepting the Co−O bond is unique to the disordered CoO 1.6 C 0.7 .…”

Fabrication and photocatalytic behavior of a novel nanocomposite hydrogels containing Fe‐octacarboxylic acid phthalocyanine

“…As can be seen that the dyes removal efficiency has a significant decrease from 25 to 35 °C and then level off, which is related to the hydrophilic property of the hydrogels network . With the hydrogels network swelling, the adsorption of the hydrogels network increase, and meanwhile, FeOCAP/MAT nanoparticles become uniform distribution to improve the excellent photocatalytic properties . Consequently, both those factors are favorable to increase the RhB removal efficiency.…”

Covalently Modified Graphenes in Catalysis, Electrocatalysis and Photoresponsive Materials

“…As commented previously, metal complexes covalently anchored to Gs have also been used as photocatalysts to promote another challenging reaction such as H 2 generation from water splitting. A series of papers have shown an improvement of the photocatalytic activity for H 2 generation by covalently attachment to the G sheets previously modified via 1,3‐dipolar cycloaddition of azomethine ylides with triphenylamine, a ruthenium complex, a SiPc or a MnPc all together with Pt NPs (Scheme ). The purpose of the covalent attachment of the organic counterpart to G is to act as light harvesting of UV and/or visible light, then, transferring electrons to G that are finally collected on Pt NPs where H 2 evolution takes place …”

“…[174] As commentedp reviously,m etal complexes covalently anchoredt oG sh ave also been used as photocatalystst op romote another challenging reactions uch as H 2 generation from water splitting. Aseries of papers have shown an improvement of the photocatalytic activity forH 2 generationb yc ovalently attachment to the Gs heets previously modified via 1,3-dipolar cycloaddition of azomethine ylides with triphenylamine, [111] a ruthenium complex, [112] aS iPc [113] or aM nPc [175] all together Legend: conduction band (CB);t riethylamine( TEA) b) Proposed reaction mechanism for CO 2 reduction by CoPc. Reprinted with permission from ref.…”