Self Assembled Monolayers(SAMs) of a series of mercapto contained azobenzene derivatives with the structure of C n H 2 n +1 AzoO(CH 2) m SH (where n =4,6,8,10,12; with m =3,5 respectively) were prepared and characteri...Self Assembled Monolayers(SAMs) of a series of mercapto contained azobenzene derivatives with the structure of C n H 2 n +1 AzoO(CH 2) m SH (where n =4,6,8,10,12; with m =3,5 respectively) were prepared and characterized.Wettability measurement of water on the SAMs demonstrates that molecular packing density in the monolayers increases while the alkyl chain in the molecules is lengthened. Both the n and m values have similar contribution to the wetting property of SAMs. The RA IR spectra reveal that the alkyl chains in the SAMs tilt away dramatically from the surface normal direction with the increase in their length. However, the orientation of azobenzene moiety is found to be influenced slightly by the alkyl chain length, which is due to the tenderness of the molecule.展开更多
The development of efficient non-precious metal catalysts is important for the large-scale application of alkaline hydrogen evolution reaction(HER).Here,we synthesized a composite catalyst of Cu and Mo_(2)C(Cu/Mo_(2)C...The development of efficient non-precious metal catalysts is important for the large-scale application of alkaline hydrogen evolution reaction(HER).Here,we synthesized a composite catalyst of Cu and Mo_(2)C(Cu/Mo_(2)C)using Anderson-type polyoxometalates(POMs)synthesized by the facile soaking method as precursors.The electronic interaction between Cu and Mo_(2)C drives the positive charge of Cu,alleviating the strong adsorption of hydrogen at the Mo site by modulating the d-band center of Mo_(2)C.By studying the interfacial water structure using in situ attenuated total reflection surface-enhanced infrared absorption spectroscopy(ATR-SEIRAS),we determined that the positively charged Cu crystals have the function of activating water molecules and optimizing the interfacial water structure.The interfacial water of Cu/Mo_(2)C contains a large amount of free water,which could facilitate the transport of reaction intermediates.Due to activated water molecules and optimized interfacial water structure and hydrogen adsorption energy,the overpotential of Cu/Mo_(2)C is 24 mV at a current density of 10 mA·cm^(-2) and 178 mV at a current density of 1000 mA·cm^(-2).This work improves catalyst performance in terms of interfacial water structure optimization and deepens the understanding of water-mediated catalysis.展开更多
文摘Self Assembled Monolayers(SAMs) of a series of mercapto contained azobenzene derivatives with the structure of C n H 2 n +1 AzoO(CH 2) m SH (where n =4,6,8,10,12; with m =3,5 respectively) were prepared and characterized.Wettability measurement of water on the SAMs demonstrates that molecular packing density in the monolayers increases while the alkyl chain in the molecules is lengthened. Both the n and m values have similar contribution to the wetting property of SAMs. The RA IR spectra reveal that the alkyl chains in the SAMs tilt away dramatically from the surface normal direction with the increase in their length. However, the orientation of azobenzene moiety is found to be influenced slightly by the alkyl chain length, which is due to the tenderness of the molecule.
基金supported by National Natural Science Foundation of China(Nos.52376060 and 51976081).
文摘The development of efficient non-precious metal catalysts is important for the large-scale application of alkaline hydrogen evolution reaction(HER).Here,we synthesized a composite catalyst of Cu and Mo_(2)C(Cu/Mo_(2)C)using Anderson-type polyoxometalates(POMs)synthesized by the facile soaking method as precursors.The electronic interaction between Cu and Mo_(2)C drives the positive charge of Cu,alleviating the strong adsorption of hydrogen at the Mo site by modulating the d-band center of Mo_(2)C.By studying the interfacial water structure using in situ attenuated total reflection surface-enhanced infrared absorption spectroscopy(ATR-SEIRAS),we determined that the positively charged Cu crystals have the function of activating water molecules and optimizing the interfacial water structure.The interfacial water of Cu/Mo_(2)C contains a large amount of free water,which could facilitate the transport of reaction intermediates.Due to activated water molecules and optimized interfacial water structure and hydrogen adsorption energy,the overpotential of Cu/Mo_(2)C is 24 mV at a current density of 10 mA·cm^(-2) and 178 mV at a current density of 1000 mA·cm^(-2).This work improves catalyst performance in terms of interfacial water structure optimization and deepens the understanding of water-mediated catalysis.
