1. High-Rate and Selective C 2 H 6 -to-C 2 H 4 Photodehydrogenation Enabled by Partially Oxidized Pd δ+ Species Anchored on ZnO Nanosheets under Mild Conditions.
- Author
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Hu Z, Zhu J, Chen R, Wu Y, Zheng K, Liu C, Pan Y, Chen J, Sun Y, and Xie Y
- Abstract
Photocatalytic C
2 H6 -to-C2 H4 conversion is very promising, yet it remains a long-lasting challenge due to the high C-H bond dissociation energy of 420 kJ mol-1 . Herein, partially oxidized Pdδ+ species anchored on ZnO nanosheets are designed to weaken the C-H bond by the electron interaction between Pdδ+ species and H atoms, with efforts to achieve high-rate and selective C2 H6 -to-C2 H4 conversion. X-ray photoelectron spectra, Bader charge calculations, and electronic localization function demonstrate the presence of partially oxidized Pdδ+ sites, while quasi-in situ X-ray photoelectron spectra disclose the Pdδ+ sites initially adopt and then donate the photoexcited electrons for C2 H6 dehydrogenation. In situ electron paramagnetic resonance spectra, in situ Fourier transform infrared spectra, and trapping agent experiments verify C2 H6 initially converts to CH3 CH2 OH via ·OH radicals, then dehydroxylates to CH3 CH2 · and finally to C2 H4 , accompanied by H2 production. Density-functional theory calculations elucidate that loading Pd site can lengthen the C-H bond of C2 H6 from 1.10 to 1.12 Å, which favors the C-H bond breakage, affirmed by a lowered energy barrier of 0.04 eV. As a result, the optimized 5.87% Pd-ZnO nanosheets achieve a high C2 H4 yield of 16.32 mmol g-1 with a 94.83% selectivity as well as a H2 yield of 14.49 mmol g-1 from C2 H6 dehydrogenation in 4 h, outperforming all the previously reported photocatalysts under similar conditions.- Published
- 2024
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