In Situ Construction of Ag/TiO2/g-C3N4 Heterojunction Nanocomposite Based on Hierarchical Co-Assembly with Sustainable Hydrogen Evolution

Abstract

The construction of heterojunctions provides a promising strategy to improve photocatalytic hydrogen evolution. However, how to fabricate a nanoscale TiO2/g-C3N4 heterostructure and hinder the aggregation of bulk g-C3N4 using simple methods remains a challenge. In this work, we use a simple in situ construction method to design a heterojunction model based on molecular self-assembly, which uses a small molecule matrix for self-integration, including coordination donors (AgNO3), inorganic titanium source (Ti(SO4)2) and g-C3N4 precursor (melamine). The self-assembled porous g-C3N4 nanotube can hamper carrier aggregation and it provides numerous catalytic active sites, mainly via the coordination of Ag+ ions. Meanwhile, the TiO2 NPs are easily mineralized on the nanotube template in dispersive distribution to form a heterostructure via an N–Ti bond of protonation, which contributes to shortening the interfacial carrier transport, resulting in enhanced electron-hole pairs separation. Originating from all of the above synergistic effects, the obtained Ag/TiO2/g-C3N4 heterogenous photocatalysts exhibit an enhanced H2 evolution rate with excellent sustainability 20.6-fold-over pure g-C3N4. Our report provides a feasible and simple strategy to fabricate a nanoscale heterojunction incorporating g-C3N4, and has great potential in environmental protection and water splitting.

Photocatalytic Activity of Silver-Based Biomimetics Composites

“…When irradiated with ultraviolet light ( Figure 10 A), direct photoexcitation of TiO 2 or ZnO with photons with energy larger than the bandgap (λ < 380 nm) is assumed, leading to the generation of electrons in the semiconductor conduction band and electron holes in the valence band [ 46 ]. The electron in the conduction band will move to the silver nanoparticles, acting as electron buffers and catalytic sites for hydrogen generation [ 11 , 12 ]. The electron holes will be quenched by the sacrificial electron donors (SO 3 2− /SO 4 2− ).…”

“…Some of the chemical modifications include the doping of TiO 2 and ZnO with metal and non-metal elements [ 7 , 8 , 9 , 10 ]. The incorporation of noble metals, such as silver (Ag), on the surfaces of these semiconductors has gained substantial interest in recent years due to the ability of the noble metal nanoparticles to reduce the fast recombination of the photogenerated charge carriers, enabling the use of visible light [ 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 ]. By reducing the photogenerated charge carriers, the UV activity is increased due to the electron transfer from the conduction band (CB) of TiO 2 or ZnO to the noble metal nanoparticles [ 12 ].…”

“…By reducing the photogenerated charge carriers, the UV activity is increased due to the electron transfer from the conduction band (CB) of TiO 2 or ZnO to the noble metal nanoparticles [ 12 ]. The photoactivity in the visible spectral range can be explained due to the surface plasmon resonance effect and charge separation by the transfer of photoexcited electrons from the metal nanoparticles to the CB of TiO 2 or ZnO [ 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 ].…”

Self-assembled functional components-doped conductive polypyrrole composite hydrogels with enhanced electrochemical performances

“…A wider peak appears at 1160-1180 cm À1 in sodium dodecyl benzenesulfonate, indicating the interaction of sulfonate group with N of sulfonamide. [39][40][41][42][43][44][45][46]…”

Fabrication of CS/GA/RGO/Pd composite hydrogels for highly efficient catalytic reduction of organic pollutants

“…5,6 Precious metal nanoparticles have special optical, catalytic, electrochemical and mechanical properties, so they have potential applications in optics, [7][8][9] catalysis, [10][11][12] microelectronics, [13][14][15] biomedicine 16,17 and many other elds. The most common used catalysts are gold, 18-20 silver 1, [21][22][23][24] and palladium. [25][26][27] In this work, palladium nanoparticles (Pd NPs) were used to catalyze the reaction of 4-NP and 2-NA with sodium borohydride (NaBH 4 ).…”