Core-Shell Nanostructured “Black” Rutile Titania as Excellent Catalyst for Hydrogen Production Enhanced by Sulfur Doping

Abstract

Modification of rutile titanium dioxide (TiO2) for hydrogen generation and water cleaning is a grand challenge due to the chemical inertness of rutile, while such inertness is a desired merit for its stability in photoelectrochemical applications. Herein, we report an innovative two-step method to prepare a core-shell nanostructured S-doped rutile TiO2 (R'-TiO2-S). This modified black rutile TiO2 sample exhibits remarkably enhanced absorption in visible and near-infrared regions and efficient charge separation and transport. As a result, the unique sulfide surface (TiO(2-x):S) boosts the photocatalytic water cleaning and water splitting with a steady solar hydrogen production rate of 0.258 mmol h(-1) g(-1). The black titania is also an excellent photoelectrochemical electrode exhibiting a high solar-to-hydrogen conversion efficiency of 1.67%. The sulfided surface shell is proved to be an effective strategy for enhancing solar light absorption and photoelectric conversion.

Hydrogen-Etched TiO2−x as Efficient Support of Gold Catalysts for Water–Gas Shift Reaction

“…However, the HRTEM images of TiO 2 -N and Au-TiO 2 -N show no obvious disordered shell near the surface region (Figure 3e,f). Thus, the results indicate that H 2 atmosphere resulted in the surface structure rearrangement and disordered shell, in agreement with the reported results [47,49] As shown in Figure 3a,d, TiO2−x-N and TiO2-N supports were decorated with Au particles (dark dots). The surface-averaged Au cluster diameters (dTEM) of Au-TiO2−x-N and Au-TiO2-N are 9.1 nm and 7.5 nm, respectively (Figure 3g,h).…”

“…However, the HRTEM images of TiO2-N and Au-TiO2-N show no obvious disordered shell near the surface region (Figure 3e,f). Thus, the results indicate that H2 atmosphere resulted in the surface structure rearrangement and disordered shell, in agreement with the reported results [47,49], so the calcination in H2 atmosphere was chosen as the hydrogen-etching technology. Furthermore, the evolution of surface structure was also confirmed by the H2-TPR results ( Figure 3i).…”

Recent Progress in Energy‐Driven Water Splitting

“…Disordered TiO 2 : Black TiO 2 was synthesized by hydrogenation process for greatly shifting the top edge of valence band of white TiO 2 , drastically narrowing its band gap and thus displaying strong absorption in visible and infrared regime 36. Naldoni et al reported the band gap narrowing of black TiO 2 nanoparticles (crystalline core and disordered shell) in the co‐presence of surface disorder and oxygen vacancies.…”

Sub-10 nm rutile titanium dioxide nanoparticles for efficient visible-light-driven photocatalytic hydrogen production

“…Self-doping with Ti 3 þ was further developed for narrowing the band of TiO 2 without the introduction of unwanted carrier recombination centres from dopants [19][20][21] , which consequently exhibited good stability and considerable activity for photocatalytic hydrogen production under visible light 20,21 . Recently, hydrogenation of crystalline TiO 2 was disclosed as a new approach to enhance the visible as well as infrared light absorption of pristine TiO 2 and subsequently triggered great interest [22][23][24][25][26][27][28] . The surface disorder of hydrogenated black TiO 2 , instead of bulk Ti 3 þ , was proposed to be responsible for the extended light absorption 23,24 .…”