Graphene supported plasmonic photocatalyst for hydrogen evolution in photocatalytic water splitting

Abstract

It is well known that the noble metal nanoparticles show active absorption in the visible region because of the existence of the unique feature known as surface plasmon resonance (SPR). Here we report the effect of plasmonic Au nanoparticles on the enhancement of the renewable hydrogen (H2) evolution through photocatalytic water splitting. The plasmonic Au/graphene/TiO2 photocatalyst was synthesized in two steps: first the graphene/TiO2 nanocomposites were developed by the hydrothermal decomposition process; then the Au was loaded by photodeposition. The plasmonic Au and the graphene as co-catalyst effectively prolong the recombination of the photogenerated charges. This plasmonic photocatalyst displayed enhanced photocatalytic H2 evolution for water splitting in the presence of methanol as a sacrificial reagent. The H2 evolution rate from the Au/graphene co-catalyst was about 9 times higher than that of a pure graphene catalyst. The optimal graphene content was found to be 1.0 wt %, giving a H2 evolution of 1.34 mmol (i.e., 26 μmolh−1), which exceeded the value of 0.56 mmol (i.e., 112 μmolh−1) observed in pure TiO2. This high photocatalytic H2 evolution activity results from the deposition of TiO2 on graphene sheets, which act as an electron acceptors to efficiently separate the photogenerated charge carriers. However, the Au loading enhanced the H2 evolution dramatically and achieved a maximum value of 12 mmol (i.e., 2.4 mmolh−1) with optimal loading of 2.0 wt% Au on graphene/TiO2 composites. The enhancement of H2 evolution in the presence of Au results from the SPR effect induced by visible light irradiation, which boosts the energy intensity of the trapped electron as well as active sites for photocatalytic activity.

Highly oxidized graphene nanosheets via the oxidization of detonation carbon

“…However, the Drifts-FTIR spectrum of OGNs (Fig. 6b) has the adsorption bands centered at wave numbers that resemble those mentioned in the previous works [35][36][37][38][39] with the band at *1073 cm -1 attributed to C-O epoxy stretching vibrations, *1224 cm -1 due to C-OH stretching vibrations, *1623 cm -1 from deformation vibration of water molecules, *1734 cm -1 from C=O carbonyl stretching and *3613 cm -1 from stretching vibration of hydroxyl groups. Thus, the GNs have been oxidized extensively, and the surface has been decorated with aforementioned carbonyl, epoxy and hydroxyl functional groups.…”

Polymer supported graphene–CdS composite catalyst with enhanced photocatalytic hydrogen production from water splitting under visible light

“…Singh etc. synthesized graphene supported plasmonic photocatalyst for hydrogen production and proved that graphene acted as an electron acceptor to suppress the recombination of charge carriers [21]. Dubale and co-workers reported that graphene exhibited synergetic effect with Cu 2 O in enhancing the absorbance of the visible light, separating the charge carriers and suppressing the photocorrosion [22].…”

Synthesis and Characterization of Au@TiO₂ NWs and their Catalytic Activity by Water Splitting: A Comparative Study with Degussa P25

“…Figure 9 shows the Raman spectra of the Au@TiO 2 -P25 catalysts. Singh et al (2014) reported that anatase phase shows major bands at ~150, 395, 515 and 638 cm −1 . These bands can be appreciated in all the TiO 2 -P25 catalysts and have been attributed to the five Raman-active modes of the anatase phase, corresponding to E g(1) , B 1g(1) , A 1g + B 1g(2) and E g (2) vibrational modes.…”

“…These bands can be appreciated in all the TiO 2 -P25 catalysts and have been attributed to the five Raman-active modes of the anatase phase, corresponding to E g(1) , B 1g(1) , A 1g + B 1g(2) and E g (2) vibrational modes. The typical Raman bands resulting from the rutile phase appear at ~143 (superimposed with the 145 cm −1 band from the anatase), 235, 455 and 612 cm −1 and can be ascribed to the B 1g , E g and A 1g vibrational modes (Singh et al, 2014;Wang et al, 2012). Only the peak at ca.…”