Electrocatalytic CO reduction(COR)offers a promising alternative approach for synthesizing valuable chemicals,potentially at a lower carbon intensity as compared to conventional chemical production.Cu-based catalysts ...Electrocatalytic CO reduction(COR)offers a promising alternative approach for synthesizing valuable chemicals,potentially at a lower carbon intensity as compared to conventional chemical production.Cu-based catalysts have shown encouraging selectivity and activity toward multi-carbon(C^(2+))products,albeit typically in the form of a mixture.Steering COR selectivity toward specific types of C2+products,such as liquid products with high energy density,remains a challenge.In this study,we developed a Cu/Zn bimetallic catalyst composite and demonstrated enhanced selectivity toward liquid products as compared to reference CuO and Cu-based catalysts,approaching 60%at a high current density of 300 mA/cm^(2).Our investigation highlights that the introduction of Zn promoted the emergence of a Cu/Zn heterojunction interface during COR.Density functional theory simulations were used to rationalize the observed differences in selectivity,revealing that interface plays a crucial role in diminishing the oxygen adsorption at the Cu-sites and modifying the adsorption energy of COR reaction intermediates,consequently leading to enhanced selectivity toward liquid products.展开更多
To achieve a flexible single-crystal multifunctional membrane,the freestanding process of a rigid epitaxial transition metal oxide thin film via a buffered water-dissolution sacrificial layer has attracted reasonable ...To achieve a flexible single-crystal multifunctional membrane,the freestanding process of a rigid epitaxial transition metal oxide thin film via a buffered water-dissolution sacrificial layer has attracted reasonable attentions.Owing to the difference in chemical potential,specific element affinity,and lattice constant between the target membrane and the sacrificial layer,the freestanding process may cause an indelible change of physics property once the target thin film is sensitive to the above factors.Here,the heterostructures composed of the generally adopted sacrificial layer Sr_(3)Al_(2)O_(6)(SAO)and LaMnO_(3)(LMO)have been systematically investigated.The electrical and magnetic properties of LMO show extreme sensitivity to the thickness of SAO(tSAO).Then we have also found that LMO/SAO heterostructures can exhibit the coexistence of two ferromagnetic phases,the significantly enhanced Curie temperature~342 K,and the large magnetoresistance-23.3%at 300 K,which is similar to the optimal-doped manganite such as La_(2/3)Sr_(1/3)MnO_(3).X-ray diffraction results show that continuously tunable strain from out-of-plane tension to relaxation and then to compression can be generated by adjusting tSAO.This strain can stabilize the migrated oxygen from LMO to SAO,which is induced by the large oxygen affinity difference between Bsite Mn and Al.It is believed that these unexpected electrical/magnetic phenomena are originated from the combined effects of interfacial element diffusion and strain.Our study provides a strategy for designing new magnetic phases,and a reference for the fundamental understanding of strongly correlated transition metal oxide systems in the freestanding process.展开更多
基金supported by ExxonMobil through the Singapore Energy Centerthe National University of Singapore and Ministry of Education(A-0009176-02-00 and A-0009176-03-00)+1 种基金A*STAR(Agency for Science,Technology and Research)under its LCERFI program(U2102d2002)the National Research Foundation(NRF)Singapore under the NRF Fellowship(NRF-NRFF13-2021-0007).
文摘Electrocatalytic CO reduction(COR)offers a promising alternative approach for synthesizing valuable chemicals,potentially at a lower carbon intensity as compared to conventional chemical production.Cu-based catalysts have shown encouraging selectivity and activity toward multi-carbon(C^(2+))products,albeit typically in the form of a mixture.Steering COR selectivity toward specific types of C2+products,such as liquid products with high energy density,remains a challenge.In this study,we developed a Cu/Zn bimetallic catalyst composite and demonstrated enhanced selectivity toward liquid products as compared to reference CuO and Cu-based catalysts,approaching 60%at a high current density of 300 mA/cm^(2).Our investigation highlights that the introduction of Zn promoted the emergence of a Cu/Zn heterojunction interface during COR.Density functional theory simulations were used to rationalize the observed differences in selectivity,revealing that interface plays a crucial role in diminishing the oxygen adsorption at the Cu-sites and modifying the adsorption energy of COR reaction intermediates,consequently leading to enhanced selectivity toward liquid products.
基金financial support from the National Natural Science Foundation of China(No.12074149)support from the Natural Science Foundation of Shandong Province(No.ZR2020QA057)+4 种基金support from the National Natural Science Foundation of China(No.51871112)the Major Basic Research Projects of Shandong Province(No.ZR2020ZD28)the 111 Project(No.B13029)support from the Taishan Scholar Project of Shandong Province(No.ts20190939)the Independent Cultivation Program of Innovation Team of Ji’nan City(No.2021GXRC043)。
文摘To achieve a flexible single-crystal multifunctional membrane,the freestanding process of a rigid epitaxial transition metal oxide thin film via a buffered water-dissolution sacrificial layer has attracted reasonable attentions.Owing to the difference in chemical potential,specific element affinity,and lattice constant between the target membrane and the sacrificial layer,the freestanding process may cause an indelible change of physics property once the target thin film is sensitive to the above factors.Here,the heterostructures composed of the generally adopted sacrificial layer Sr_(3)Al_(2)O_(6)(SAO)and LaMnO_(3)(LMO)have been systematically investigated.The electrical and magnetic properties of LMO show extreme sensitivity to the thickness of SAO(tSAO).Then we have also found that LMO/SAO heterostructures can exhibit the coexistence of two ferromagnetic phases,the significantly enhanced Curie temperature~342 K,and the large magnetoresistance-23.3%at 300 K,which is similar to the optimal-doped manganite such as La_(2/3)Sr_(1/3)MnO_(3).X-ray diffraction results show that continuously tunable strain from out-of-plane tension to relaxation and then to compression can be generated by adjusting tSAO.This strain can stabilize the migrated oxygen from LMO to SAO,which is induced by the large oxygen affinity difference between Bsite Mn and Al.It is believed that these unexpected electrical/magnetic phenomena are originated from the combined effects of interfacial element diffusion and strain.Our study provides a strategy for designing new magnetic phases,and a reference for the fundamental understanding of strongly correlated transition metal oxide systems in the freestanding process.
