Details

Autor(en) / Beteiligte

• Kumar, Niharika
• Mishra, Rajashree P
• Dash, Bibek
• Bastia, Sweta
• Chaudhary, Yatendra S

Titel

The synergistic chemical coupling of nanostructured MoS with nitrogen-deficient 2-D triazine-based polymeric for efficient and selective CO photocatalytic conversion to CO

Ist Teil von

• Journal of materials chemistry. A, Materials for energy and sustainability, 2023-10, Vol.11 (38), p.2839-2853

Erscheinungsjahr

2023

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• Donor-acceptor-type heterostructured photocatalysts have been synthesized by coupling triazine-based mesoporous polymeric C 3 N x with varied loading concentrations of MoS 2 , via a template-directed thermal decomposition synthesis followed by hydrothermal reaction, to further improve CO 2 reduction efficacy and tune the selectivity. The appearance of two peaks at 12.7° (100) and 27.8° (002) confirms the formation of a tris- s -triazine polymeric framework, where, upon modification with MoS 2 , a slight shift was observed in the latter peak to a lower 2 value, which implies a shorter interlayer stacking distance. The appearance of the XPS peak at 287.1 eV for the formation of C-S and the increased peak intensity at 235.5 eV corresponding to Mo 6+ in the case of nitrogen-deficient MS-m-C 3 N x -3 compared to that of the MS-m-CN-3 suggest a chemical coupling between the MoS 2 and CN/C 3 N x . The optimized MS-m-C 3 N x -3 exhibits a higher CO formation rate (2095.05 μmol g −1 ) and faradaic efficiency of ∼31%, which is nearly 3-fold higher than those of MS-m-CN (579.29 μmol g −1 and 11%). The formation of CO was further confirmed by 13 C NMR and GC-MS analysis, which shows the production of 12 CO with an m / z value of 28. PEC measurements reveal more positive onset potential in the case of MS-m-C 3 N x -3 than in MS-m-CN-3 . Furthermore, the bare m-CN and m-C 3 N x exhibit two notable CO 2 desorption peaks; however, upon modification with MoS 2 nanocrystals, MS-m-C 3 N x -3 shows a single intense desorption peak at a higher temperature, revealing a single type of active site, suggesting selectivity for single-product formation, whereas MS-m-CN-3 exhibits a slight rise at the beginning of the peak, revealing the presence of more than one active site and corroborating the DFT calculations. The enhanced CO 2 conversion efficiency of MS-m-C 3 N x -3 compared to MS-m-CN-3 is due to the combination of an efficient charge separation and transfer kinetics, as revealed by the decrease in the average lifetime of photogenerated electrons (1.91 ns), lower charge transfer resistance, increased electron density upon illumination, and broadening of the VB (0.28 eV) in the case of MS-m-C 3 N x -3 (as opposed to 0.05 eV in MS-m-CN-3 ). The chemically coupled MOS 2 with nitrogen deficient 2-D triazine polymeric m-C 3 N x photocatalyst drives the selective and efficient photocatalytic reduction of CO2 to CO (FE: 31%), - three folds higher than that of MoS2 decorated mpg-C 3 N 4 .