Photocatalytic coupling of thiols is a promising green approach to obtain disulfides.In this work,we report a stable pyrene-based MOF(Ni-PTTB)and its exfoliated two-dimensional(2D)nanobelts(Ni-PTTB-NB),which were prep...Photocatalytic coupling of thiols is a promising green approach to obtain disulfides.In this work,we report a stable pyrene-based MOF(Ni-PTTB)and its exfoliated two-dimensional(2D)nanobelts(Ni-PTTB-NB),which were prepared through the self-assembly of 1,3,6,8-tetrakis(3-carboxyphenyl)pyrene(H_(4)PTTB)and Ni(NO_(3))_(2)·6H_(2)O.Taking advantages of the uniformly dispersedπ-conjugated pyrene units,the obtained pyrene-based MOFs displayed visible-light absorption as well as intriguing optoelectronic properties.Interestingly,the 2D Ni-PTTB-NB showed obviously improved charge separation and migration compared to the pristine bulk Ni-PTTB,as revealed by a range of photoelectrochemical tests as well as Kelvin probe force microscopy(KPFM)measurements.Importantly,the Ni-PTTB-NB exhibited exceptional catalytic performance in the photocatalytic coupling of thiols in the air,giving rise to a 99%conversion of thiols and 99%selectivity of the disulfide products.Mechanism studies disclosed that the thiyl radicals are important intermediate in the catalytic process,which are obtained through the oxidation of thiols by the photogenerated holes.This work provides insights into the future design and development of 2D MOFs for the photocatalytic synthesis of high-value organic compounds.展开更多
The extraordinary performances of phase-coexisting ferroelectrics are significantly affected by not only the phase constitution but also the motion of domain walls.The study on the role of phase coexistence in the for...The extraordinary performances of phase-coexisting ferroelectrics are significantly affected by not only the phase constitution but also the motion of domain walls.The study on the role of phase coexistence in the formation of ferroelectric and ferroelastic domain microstructures is of great importance to explain the enhanced piezoelectric properties.In situ high-energy diffraction and the Rayleigh law are utilized to reveal the interplay of phase constitution and domain configuration to the macroscopic electromechanical coupling effect in the morphotropic phase boundary composition of 0.365BiScO_(3)–0.635PbTiO_(3) during the application of a weak electrical loading in the present study.It was found that anisotropic phase transition and domain switching occur in polycrystalline ferroelectric ceramics and a phase transition occurs dramatically beyond the coercive field.Taking into account the important role of coupled ferroelectric and ferroelastic domain microstructures,we conceived a configuration of monoclinic domains coexisting with and bridging the tetragonal domains.The existence of bridging domains would provide an insight into the interplay of the phase and domain and explains the piezoelectric performance in the vicinity of morphotropic phase boundaries.展开更多
基金the National Natural Science Foundation of China(22001198)the Education Department of Guangdong Province(2022ZDJS027)+1 种基金the General Financial Grant from the China Postdoctoral Science Foundation(2019M662809)Municipal Science and Technology Bureau(Jiangke 2021-76).
文摘Photocatalytic coupling of thiols is a promising green approach to obtain disulfides.In this work,we report a stable pyrene-based MOF(Ni-PTTB)and its exfoliated two-dimensional(2D)nanobelts(Ni-PTTB-NB),which were prepared through the self-assembly of 1,3,6,8-tetrakis(3-carboxyphenyl)pyrene(H_(4)PTTB)and Ni(NO_(3))_(2)·6H_(2)O.Taking advantages of the uniformly dispersedπ-conjugated pyrene units,the obtained pyrene-based MOFs displayed visible-light absorption as well as intriguing optoelectronic properties.Interestingly,the 2D Ni-PTTB-NB showed obviously improved charge separation and migration compared to the pristine bulk Ni-PTTB,as revealed by a range of photoelectrochemical tests as well as Kelvin probe force microscopy(KPFM)measurements.Importantly,the Ni-PTTB-NB exhibited exceptional catalytic performance in the photocatalytic coupling of thiols in the air,giving rise to a 99%conversion of thiols and 99%selectivity of the disulfide products.Mechanism studies disclosed that the thiyl radicals are important intermediate in the catalytic process,which are obtained through the oxidation of thiols by the photogenerated holes.This work provides insights into the future design and development of 2D MOFs for the photocatalytic synthesis of high-value organic compounds.
基金supported by the National Natural Science Foundation of China(Grants 21701126,21801013,21825102,21731001,and 21590793)the Fundamental Research Funds for the Central Universities,China(Grant FRF-TP-18-001C2)+3 种基金financial support from the China Scholarship Council and the help from Naike ShiNSF’s ChemMatCARS Sector 15 is principally supported by the Divisions of Chemistry(CHE)Materials Research(DMR),National Science Foundation,under Grant No.NSF/CHE-1834750The use of the Advanced Photon Source,an Office of Science User Facility operated for the U.S.Department of Energy(DOE)Office of Science by Argonne National Laboratory,was supported by the U.S.DOE under Contract No.DE-AC02-06CH11357.
文摘The extraordinary performances of phase-coexisting ferroelectrics are significantly affected by not only the phase constitution but also the motion of domain walls.The study on the role of phase coexistence in the formation of ferroelectric and ferroelastic domain microstructures is of great importance to explain the enhanced piezoelectric properties.In situ high-energy diffraction and the Rayleigh law are utilized to reveal the interplay of phase constitution and domain configuration to the macroscopic electromechanical coupling effect in the morphotropic phase boundary composition of 0.365BiScO_(3)–0.635PbTiO_(3) during the application of a weak electrical loading in the present study.It was found that anisotropic phase transition and domain switching occur in polycrystalline ferroelectric ceramics and a phase transition occurs dramatically beyond the coercive field.Taking into account the important role of coupled ferroelectric and ferroelastic domain microstructures,we conceived a configuration of monoclinic domains coexisting with and bridging the tetragonal domains.The existence of bridging domains would provide an insight into the interplay of the phase and domain and explains the piezoelectric performance in the vicinity of morphotropic phase boundaries.
