Black N/H‐TiO₂ Nanoplates with a Flower‐Like Hierarchical Architecture for Photocatalytic Hydrogen Evolution

Abstract

A facile two‐step strategy was used to prepare black of hydrogenated/nitrogen‐doped TiO2 nanoplates (NHTA) with a flower‐like hierarchical architecture. In situ nitriding and self‐assembly was realized by hydrothermal synthesis using tripolycyanamide as a N source and as a structure‐directing agent. After thorough characterization, it was found that the hydrogenation treatment did not damage the flower‐like architecture but distorted the anatase crystal structure and significantly changed the band structure of NHTA owing to the increased concentration of oxygen vacancies, hydroxyl groups, and Ti3+ cations. Under AM 1.5 illumination, the photocatalytic H2 evolution rate on the black NHTA was approximately 1500 μmol g−1 h−1, which was much better than the N‐doped TiO2 nanoplates (≈690 μmol g−1 h−1). This improvement in the hydrogen evolution rate was attributed to a reduced bandgap, enhanced separation of the photogenerated charge carriers, and an increase in the surface‐active sites.

Controllable Synthesis of Mesoporous TiO2 Polymorphs with Tunable Crystal Structure for Enhanced Photocatalytic H2 Production

“…To elaborate the band structure of the products, the valence band XPS spectra and Mott-Schottky plots were employed to measure the valence band position and flat band potential, respectively. [42] The relatively smaller slopes of A 29 R 46 B 25 and A 29 R 71 as compared with those of A 100 and R 100 , suggesting a faster charge transfer and an increase of donor density (N d ). [41] The Mott-Schottky plots (Figure 5c) of these samples exhibit a positive slope, which is a typical n-type semiconductor.…”

Ti‐rich TiO2 Tubular Nanolettuces by Electrochemical Anodization for All‐Solid‐State High‐Rate Supercapacitor Devices

“…The XP spectrumo ft he top region illustrates that only the Ti 4 + chemical state exists on the surfaceo f the nanotubes. [26] It shows Ti 2p 3/2 and Ti 2p 1/2 peaks located at 458.5 and 464.2 eV owing to spin-orbit splitting, respectively. [27] Three-electrode configuration Figure 4A shows at ypicalC Vc urve of the optimum (see Figure S7 in the Supporting Information) TAT electrode in the potentialw indow of À1.25 to 1.25 V[ vs. Ag/AgCl (3 m KCl)], which can be divided into three different regions:E DLC (right), pseudocapacitive (PC, middle), and battery-like (left).…”

Wide‐bandgap HfO2‐V2O5 nanowires heterostructure for visible light‐driven photocatalytic degradation

“…Bandgap narrowing is therefore an important issue that is under intensive investigation. Bandgap narrowing has been done through doping, for example, a nonmetal (N, C, S, F) or metal ions (Fe, Cu, V, Pt, Fe, Cr, Co, B, and Mn) are used to dope TiO 2 …”

“…Bandgap narrowing is therefore an important issue that is under intensive investigation. Bandgap narrowing has been done through doping, for example, a nonmetal (N, C, S, F) [11][12][13][14][15][16][17] or metal ions (Fe, Cu, V, Pt, Fe, Cr, Co, B, and Mn) are used to dope TiO 2 . [18][19][20][21][22][23][24][25][26] Ideally, a direct way to utilize the visible light is the use of a narrow bandgap photocatalyst.…”