The single-pot production of Pd@Pt core-shell structures is a promising approach as it offers large surface area,catalytic capability,and stability.In this work,we established a single-pot process to produce Pd@Pt cor...The single-pot production of Pd@Pt core-shell structures is a promising approach as it offers large surface area,catalytic capability,and stability.In this work,we established a single-pot process to produce Pd@Pt core-shell nanodendrites with tunable composition,shape and size for optimal electrochemical activity.Pd@Pt nanodendrites with diverse compositions were synthesized by tuning the ratios of Pd and Pt sources in an aqueous environment using cetyltrimethylammonium chloride,which functioned as both the surfactant and the reducing agent at an elevated temperature(90°C).The synthesized Pd5@Pt5 nanodendrites showed exceptional electrochemical action toward the methanol oxidation reaction related with another compositional Pd@Pt nanodendrites and conventional Pt/C electrocatalysts.In addition,Pd5@Pt5 nanodendrites exhibited good CO tolerance owing to their surface features and the synergistic effect among Pt and Pd.Meanwhile,nanodendrites with a Pt-rich surface provided exceptional catalytic active sites.Compared with the conventional Pt/C electrocatalyst,the anodic peak current obtained by Pd5@Pt5 nanodendrites was 3.74 and 2.18 times higher in relations of mass and electrochemical active surface area-normalized current density,respectively.This approach offers an attractive strategy to design electrocatalysts with unique structures and outstanding catalytic performance and stability for electrochemical energy conversion.展开更多
The reactions of 18-crown-6with Na 2M(SCN)4(M=Pd,Pt )were studied and the complexNa (18-C-62 (H2O) nPd(SCN)4 n and complex2Na (18-C-6) 2 (H 2 O nPt (SCN) 4 n were characterized by ele-mental analysis,IR and X-ray diff...The reactions of 18-crown-6with Na 2M(SCN)4(M=Pd,Pt )were studied and the complexNa (18-C-62 (H2O) nPd(SCN)4 n and complex2Na (18-C-6) 2 (H 2 O nPt (SCN) 4 n were characterized by ele-mental analysis,IR and X-ray diffra ction analysis.The complexes belon g to monoclinic,space group P2 1 /n with cell dimensions,1:a=1.05734(7),b=1.42250(10),c=1.47762(10)nm,β=107.5330(10)°,V=2.1192(2)nm 3 ,Z =2,D calcd =1.460g·cm -3 ,F(000)=964,R 1 =0.0406,w R 2 =0.1264and2:a=1.05985(19),b=1.4237(3),c=1.4744(3)nm,β=107.096(3)°,V=2.1264(7)nm 3 ,Z =2,D calcd =1.690g·cm -3 ,F(000)=1028,R 1 =0.0292,w R 2 =0.0859.In the solid state,the comp lexes1and2show an one-dimensnal chain ofNa (18-C-6)狚 2 (H 2O)2+ complex cations andM(SCN) 4 2- (M=Pd,Pt )complex anions bridged by Na-N in-teractions.展开更多
Catalytically-grown carbon nanofibers of two different conformations, fishbone and parallel types of the arrangement of carbon layers, were employed as the support of Pd-Pt metal catalysts for the hydrogenation of nap...Catalytically-grown carbon nanofibers of two different conformations, fishbone and parallel types of the arrangement of carbon layers, were employed as the support of Pd-Pt metal catalysts for the hydrogenation of naphthalene to tetralin. The sulfur tolerance of the catalyst system was investigated with the addition of 0.05% thiophene to the reactant of naphthalene in the process. The dispersion of Pd-Pt metal particles on the support was observed with a HREM and a pulsed hydrogen chemisorption method. The hydrogenation reaction of naphthalene was carried out in a CSTR at 250℃ and with the hydrogen pressure of 6 MPa. The results showed that the Pd-Pt catalyst supported on the carbon nanofibers was active in the process. The Pd-Pt metal catalyst supported on the parallel carbon nanofibers showed a higher sulfur tolerance than that on the fishbone carbon nanofibers. The reason may be attributed to their different conformations of the carbon layers, which leads to the different interaction of carbon layers with the supported metal particles.展开更多
基金the Basic Science Research Program of the National Research Foundation(NRF)of Korea(Nos.2019R1A6A1A11053838,2022R1A4A3033528,and 2022R1F1A1063285)Korea Agency for Infrastructure Technology Advancement(KAIA)funded by the Ministry of Land,Infrastructure,and Transport(No.21CTAP-C163795-01)Prof.M.Y.Choi acknowledges the Korea Basic Science Institute(National Research Facilities and Equipment Center)grant funded by the Ministry of Education(Nos.2019R1A6C1010042 and 2021R1A6C103A427).
文摘The single-pot production of Pd@Pt core-shell structures is a promising approach as it offers large surface area,catalytic capability,and stability.In this work,we established a single-pot process to produce Pd@Pt core-shell nanodendrites with tunable composition,shape and size for optimal electrochemical activity.Pd@Pt nanodendrites with diverse compositions were synthesized by tuning the ratios of Pd and Pt sources in an aqueous environment using cetyltrimethylammonium chloride,which functioned as both the surfactant and the reducing agent at an elevated temperature(90°C).The synthesized Pd5@Pt5 nanodendrites showed exceptional electrochemical action toward the methanol oxidation reaction related with another compositional Pd@Pt nanodendrites and conventional Pt/C electrocatalysts.In addition,Pd5@Pt5 nanodendrites exhibited good CO tolerance owing to their surface features and the synergistic effect among Pt and Pd.Meanwhile,nanodendrites with a Pt-rich surface provided exceptional catalytic active sites.Compared with the conventional Pt/C electrocatalyst,the anodic peak current obtained by Pd5@Pt5 nanodendrites was 3.74 and 2.18 times higher in relations of mass and electrochemical active surface area-normalized current density,respectively.This approach offers an attractive strategy to design electrocatalysts with unique structures and outstanding catalytic performance and stability for electrochemical energy conversion.
文摘The reactions of 18-crown-6with Na 2M(SCN)4(M=Pd,Pt )were studied and the complexNa (18-C-62 (H2O) nPd(SCN)4 n and complex2Na (18-C-6) 2 (H 2 O nPt (SCN) 4 n were characterized by ele-mental analysis,IR and X-ray diffra ction analysis.The complexes belon g to monoclinic,space group P2 1 /n with cell dimensions,1:a=1.05734(7),b=1.42250(10),c=1.47762(10)nm,β=107.5330(10)°,V=2.1192(2)nm 3 ,Z =2,D calcd =1.460g·cm -3 ,F(000)=964,R 1 =0.0406,w R 2 =0.1264and2:a=1.05985(19),b=1.4237(3),c=1.4744(3)nm,β=107.096(3)°,V=2.1264(7)nm 3 ,Z =2,D calcd =1.690g·cm -3 ,F(000)=1028,R 1 =0.0292,w R 2 =0.0859.In the solid state,the comp lexes1and2show an one-dimensnal chain ofNa (18-C-6)狚 2 (H 2O)2+ complex cations andM(SCN) 4 2- (M=Pd,Pt )complex anions bridged by Na-N in-teractions.
文摘Catalytically-grown carbon nanofibers of two different conformations, fishbone and parallel types of the arrangement of carbon layers, were employed as the support of Pd-Pt metal catalysts for the hydrogenation of naphthalene to tetralin. The sulfur tolerance of the catalyst system was investigated with the addition of 0.05% thiophene to the reactant of naphthalene in the process. The dispersion of Pd-Pt metal particles on the support was observed with a HREM and a pulsed hydrogen chemisorption method. The hydrogenation reaction of naphthalene was carried out in a CSTR at 250℃ and with the hydrogen pressure of 6 MPa. The results showed that the Pd-Pt catalyst supported on the carbon nanofibers was active in the process. The Pd-Pt metal catalyst supported on the parallel carbon nanofibers showed a higher sulfur tolerance than that on the fishbone carbon nanofibers. The reason may be attributed to their different conformations of the carbon layers, which leads to the different interaction of carbon layers with the supported metal particles.
