C,N-Codoped TiO₂ with a Nitrogen-Doped Carbon Coating Derived from 2,6-Diaminopyridine for Visible Light-Induced Photocatalytic Hydrogen Evolution

Abstract

Nitrogen-doped carbon-wrapped C,N-codoped TiO2 (CN@C,N-TiO2) was successfully prepared using a facile and efficient method involving hydrolysis and calcination under Ar using tetrabutyl titanate and 2,6-diaminopyridine as the precursors. X-ray photoelectron spectroscopy (XPS) and valence band XPS measurements reveal the successful codoping of interstitial carbon and nitrogen into TiO2, which leads to a visible-light absorption of up to ∼550 nm in the UV–vis diffuse reflectance spectra. Raman spectra and high-resolution transmission electron microscopy results show that N-doped carbon exists on the surface of C,N-TiO2, which gives rise to the efficient separation of photoexcited charge carriers, as determined by photoluminescence and electrochemical impedance spectroscopy. Benefiting from the combined effects of a surface-coated N-doped carbon layer and C,N-codoping, the photocatalyst calcined at 450 °C exhibits remarkable visible-light activity toward the hydrogen evolution reaction in the water splitting process with a H2 production rate of 833.2 μmol h–1 g–1 under 94 mW cm–2 visible-light illumination (λ > 420 nm). Moreover, the representative CN@C,N-TiO2 sample can maintain its activity for at least 40 h.

Nanolayered Heterostructures of N-Doped TiO2 and N-Doped Carbon for Hydrogen Evolution

“…Hence, many valuable efforts around doping have been executed. Particularly, nitrogen-doped carbon materials are considered an excellent strategy for improving its conductivity and ability of H 2 production. , However, compared to the preparation of TiO 2 by using Ti­(OC 4 H 9 ) 4 and the preparation of TiO 2 and carbon composite by traditional physical adsorption methods, we applied nitriding MXene and in situ growth to synthesize doped TiO 2 /C composite. − The nanolayered heterostructure of N-TiO 2 /NC presents excellent orderliness and the intimate connection between TiO 2 and carbon, which is beneficial to the improvement of charge transfer and photocatalytic performance.…”

Fabrication of tailored rod-shaped carbon nitride, g-C3N4, decorated with MoSe2 flowers for the catalytic reduction of nitrophenol, organic dye degradation and biocompatibility studies

“…It is also to be mentioned that carbon material with a π-conjugated system allows for the transfer and storage of electrons, favoring the reduction processes. 61 Similarly, high spin density and local positive charge over the carbon atom of b-CN could be another reason for the adsorption of BH 4 − through electrostatic adsorption phenomena. 56 Moreover, the uncoordinated edges of the flower MoSe 2 residing over b-CN contain active sites which is beneficial for catalytic activity.…”

One-pot hydrothermal preparation of capsule-like nanocomposites of C/Ce-co-doped ZnO supported on graphene to enhance photodegradation

“…On the other hand, many studies stated that carbon-doping into TiO 2 and ZnO creates a new valence band, resulting in narrow band gaps for the obtained materials. 13,27,28 In contrast to doping with foreign metals, doping with non-metal elements hardly generates the recombination centers, which significantly improves the photocatalytic degradation of organic compounds on ZnO under visible light. Furthermore, the doping with both Ce and C increases the oxygen vacancies as electronic traps to prevent the electrons and holes from recombining and increases the lifetime of the charge carriers.…”