Abstract
TiO2 is an ideal photocatalyst candidate except for its large bandgap and fast charge recombination. A novel laminated junction composed of defect‐controlled and sulfur‐doped TiO2 with carbon substrate (LDC‐S‐TiO2/C) is synthesized using the 2D transition metal carbides (MXenes) as a template to enhance light absorption and improve charge separation. The prepared LDC‐S‐TiO2/C catalyst delivers a high photocatalytic H2 evolution rate of 333 µmol g−1 h−1 with a high apparent quantum yield of 7.36% at 400 nm and it is also active even at 600 nm, resulting into a 48 time activity compared with L‐TiO2/C under visible light irradiation. Further theoretical modeling calculation indicates that such novel approach also reduces activation energy of hydrogen production apart from broadening the absorption wavelength, facilitating charge separation, and creating a large surface area substrate. This synergic effect can also be applied to other photocatalysts' modification. The study provides a novel approach for synthesis defective metal oxides based hybrids and broaden the applications of MXene family.
Highlights
CdS,[4] ZnO,[5] C3N4,[6] and WO3,[7] were used to water splitting by harnessing solar fast charge recombination
2D Ti3C2 MXenes were synthesized via the selectively etching of Ti3AlC2 MAX phases
Because the reduction of H+ and the release of H2 mainly occur on carbon substrate, we only investigated the effects of DC on the hydrogen evolution activity
Summary
The S2p peaks at 162.0, 163.7, and 167.6 eV ping analysis of L-S-TiO2 sample without carbon (Figure S9, can be assigned to S2p3/2, S2p1/2, and S O bonds, respectively Supporting Information) indicated that sulfur atoms have been (Figure 2f). The total structure has been well pre- cate that the LDC-S-TiO2/C can expose more S-doped TiO2 for served during air oxidation process, as shown in Figure S2 the light absorption and favor the hydrogen evolution reaction in the Supporting Information. The H2 generation of LDC-S-TiO2/C amounts to 12505 μmol g−1, likely owing to reduced defect concentration, enlarged SSA and the reduced excitation energy proved by modeling calculation later This enhancement of approximately three times is attributed to the SSA. The peak intensities of C S, S Ti O, and S O bonds do not change, suggesting that the structure of LDC-S-TiO2/C can be well preserved after longtime cycles
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