Green chemistry synthesis of a nanocomposite graphene hydrogel with three-dimensional nano-mesopores for photocatalytic H2 production

Abstract

In this work, we have developed a nanocomposite graphene hydrogel (NGH) based on green chemistry, employing vitamin C (VC) to attain a supramolecular 3D network of hybrid nanostructured materials. Here, it is shown that the hydrogel is an appropriate and robust host for stable a TiO 2 semiconductor catalyst sensitized with visible light responsive nanostructured particles. The NGH is tailored with well-defined nano-mesopores, a large surface area, a highly dispersive nanosheet-nanorods-nanoparticle composite, and enhance visible light absorption. Finally, we demonstrate practical applications of utilizing the NGH with water containing pores for photocatalytic H 2 production. An important pragmatic consideration of using a NGH is the ease of separation and recovery of the nanosized catalyst after the photoreaction which would otherwise require extensive and expensive nanofiltration.

Fabrication of wheat grain textured TiO2/CuO composite nanofibers for enhanced solar H2 generation and degradation performance

“…To determine the photocatalytic activity of these asfabricated NFs, we utilized them for hydrogen production from photocatalytic water splitting [9,41]. In this case, we found that the H 2 evolution rate can be immensely enhanced by introducing copper nanoparticles into the bare TiO 2 NFs and optimizing its performance by tuning the amount of CuO composited.…”

Striving Toward Noble-Metal-Free Photocatalytic Water Splitting: The Hydrogenated-Graphene–TiO2 Prototype

“…Considering several other GR/TiO 2 composites synthesized and reduced by different methods, [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30] due to the higher work function, Φ GR = -4.42 eV (vs. vacuum) and Φ TiO2 = -4. 2 eV, 21,80 GR acts as the electron acceptor and conductor to capture and shuttle photoexcited electrons from the conduction band of TiO 2 , efficiently prolonging the lifetime and improving the mobility of electrons (whilst photogenerated holes are scavenged by the methanol sacrificial agent) and thus, facilitating H 2 production.…”

“…[15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30] GR sheets efficiently suppress the recombination of photoinduced electron-hole pairs, accelerate the transfer of electrons, enhance the surface-adsorbed quantity of target molecules via π-π and electrostatic interactions, as well as extend the absorption range to the visible light region by either narrowing the bap gap or introducing an additional gap. [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30] Despite the fact that a cornucopia of scientific studies devoted to GR/TiO 2 composite materials has been reported, our fundamental understanding of these materials appears to have reached a plateau. Meanwhile, combining TiO 2 with fully hydrogenated graphene (known as 'graphane') or partially/half-hydrogenated graphene (as 'graphone') has not been achieved and remains at the fore front of photoelectrochemical research.…”

“…The origin of such properties is largely due to simultaneously enhanced adsorption capacity, extended light absorption, superior stability and excellent electron transport. [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30] TiO 2 is the most widely used photocatalyst with a high propensity for generating pairs of electrons and holes upon photon absorption. 31,32 A noteworthy obstacle is that both the rapid recombination of these charge carriers within nanoseconds and the limited absorption in the near-UV region renders diminished either efficiency or activity of the photocatalytic reaction and partially limits its wide use in practical applications.…”

Fabrication of Hierarchically Porous Reduced Graphene Oxide/SnIn4S8 Composites by a Low-Temperature Co-Precipitation Strategy and Their Excellent Visible-Light Photocatalytic Mineralization Performance

“…Reduced graphene oxide (RGO) has large specific surface area, superior electrical conductivity, high carrier mobility, and excellent mechanical properties, and is usually used as a good support to enhance the photocatalytic activities of some photocatalysts [27][28][29][30][31]. Herein, we first report a facile and simple synthesis of reduced graphene oxide/SnIn 4 S 8 (RGO/SnIn 4 S 8 ) composites with strong mineralization ability by a low-temperature co-precipitation method.…”