Transition metal and nitrogen co-doped carbon(M–N/C) catalysts are recognized as the most prospective alternatives for platinum-based electro-catalysts towards oxygen reduction reaction(ORR) in polymer electrolyte fu...Transition metal and nitrogen co-doped carbon(M–N/C) catalysts are recognized as the most prospective alternatives for platinum-based electro-catalysts towards oxygen reduction reaction(ORR) in polymer electrolyte fuel cells. Recently, significant progress has been achieved in the identification and regulation of active sites of this kind of catalysts. In this mini review,we summarize the techniques and strategies to identify active sites in M–N/C catalysts, the main debates on active sites types, the measurement method for active site density, the reactivity descriptors for M–N/C catalysts, and directions to the design of ORR M–N/C catalysts.展开更多
Three compounds with nitrocarbazole frameworks were synthesized and their electrochemical reversibility as organic electrocatalysts was studied by cyclic voltammetry. The electrochemical reversibility and oxidation‐r...Three compounds with nitrocarbazole frameworks were synthesized and their electrochemical reversibility as organic electrocatalysts was studied by cyclic voltammetry. The electrochemical reversibility and oxidation‐reduction potential of the compounds were greatly affected by their substituents. The oxidation‐reduction potential of the compound with an electron‐donating group was negative, while that of the compound with an electron‐withdrawing group on the carbazole framework was positive. The electrocatalytic oxidation activities of the nitrocarbazole compounds were investigated through cyclic voltammetry and controlled potential electrolysis at room tem‐perature. The electrocatalysts showed excellent selectivity for p‐methoxybenzyl alcohol, converting it to the corresponding aldehyde through electro‐oxidation with just 2.5 mol%of the electrocata‐lysts presented. The electrocatalysts maintained their excellent electroredox activity following re‐cycling.展开更多
Anode electro-catalysts for direct dimethyl-ether fuel cell (DDFC), Pt/C, PtRu/C (1∶1) and PtSn/C (3∶2), were prepared by chemical impregnation-reductio n method with formaldehyde as the reductant. DME electro-oxida...Anode electro-catalysts for direct dimethyl-ether fuel cell (DDFC), Pt/C, PtRu/C (1∶1) and PtSn/C (3∶2), were prepared by chemical impregnation-reductio n method with formaldehyde as the reductant. DME electro-oxidation and adsorptio n at Pt electrode and Pt electro-catalysts were investigated by Cyclic Voltammet ry(CV), Quasi-steady state polarization and Gas Chromatography(GC). CV showed th at there were two current peaks of DME electro-oxidation at Pt electrode around 0.8V (vs RHE); DME was adsorbed at Pt electrode more weakly and slowly than oxyg en, methanol, even hydrogen; the onset potential of DME oxidation was 50mV less than that of methanol, and DME peak potential 110 mV lower, thus more advantageo us for using in fuel cells than methanol. GC showed that small amount of HCHO wa s generated during DME electro-oxidation. The mechanism of DME electro-oxidation was proposed. Among the three electro-catalysts (Pt/C, PtRu/C and PtSn/C), Pt a lloy catalysts, especially PtRu/C, showed a higher performance toward DME electr o-oxidation, as in the case of methanol. Temperature experiments showed that bot h DME electro-oxidation and adsorption on Pt and Pt alloy catalysts were favored with increased temperature.展开更多
The performance of electrocatalytic oxygen reduction on Mo-Ru-X (X=S, Se, Te) was investigated. The catalysts were synthesized by the carbonyl complexes decomposition method. The activities of the catalysts were measu...The performance of electrocatalytic oxygen reduction on Mo-Ru-X (X=S, Se, Te) was investigated. The catalysts were synthesized by the carbonyl complexes decomposition method. The activities of the catalysts were measured by potentiodynamic and AC impedance. The micro-structures and compositions were characterized by XRD, TEM and EDS. Transmission electron microscopy (TEM) measurements reveal that the catalyst material is of amorphous Ru cluster chalcogenides in the nanoscale range. The electrochemical experiments show that the activity of Mo-Ru-Se is the highest, and peak current density is 3.32 mA·cm-2. However, Mo-Ru-Se is sensitive to methanol in methanol-containing electrolyte, and the activity decreased with the increasing of methanol concentration. The activity of Mo-Ru-S is poorer than Mo-Ru-Se, the peak current density is 2.80 mA·cm-2, the behavior of methanol effect on the activity is similar to Mo-Ru-Se. The tolerant-methanol performance of Mo-Ru-Te is the best in the three, but activity is not high, peak current density is 2.69 mA·cm-2 only.展开更多
基金supported by National Science and Technology Major Project (2017YFB0102900)the National Natural Science Foundation of China (21633008, 21433003, U1601211, 21733004)+1 种基金Jilin Province Science and Technology Development Program (20150101066JC, 20160622037JC, 20170203003SF, 20170520150JH)Hundred Talents Program of Chinese Academy of Sciences and the Recruitment Program of Foreign Experts (WQ20122200077)
文摘Transition metal and nitrogen co-doped carbon(M–N/C) catalysts are recognized as the most prospective alternatives for platinum-based electro-catalysts towards oxygen reduction reaction(ORR) in polymer electrolyte fuel cells. Recently, significant progress has been achieved in the identification and regulation of active sites of this kind of catalysts. In this mini review,we summarize the techniques and strategies to identify active sites in M–N/C catalysts, the main debates on active sites types, the measurement method for active site density, the reactivity descriptors for M–N/C catalysts, and directions to the design of ORR M–N/C catalysts.
基金supported by the Special Program for the National Basic Research Program of China(973 Program,2012CB722604)~~
文摘Three compounds with nitrocarbazole frameworks were synthesized and their electrochemical reversibility as organic electrocatalysts was studied by cyclic voltammetry. The electrochemical reversibility and oxidation‐reduction potential of the compounds were greatly affected by their substituents. The oxidation‐reduction potential of the compound with an electron‐donating group was negative, while that of the compound with an electron‐withdrawing group on the carbazole framework was positive. The electrocatalytic oxidation activities of the nitrocarbazole compounds were investigated through cyclic voltammetry and controlled potential electrolysis at room tem‐perature. The electrocatalysts showed excellent selectivity for p‐methoxybenzyl alcohol, converting it to the corresponding aldehyde through electro‐oxidation with just 2.5 mol%of the electrocata‐lysts presented. The electrocatalysts maintained their excellent electroredox activity following re‐cycling.
文摘Anode electro-catalysts for direct dimethyl-ether fuel cell (DDFC), Pt/C, PtRu/C (1∶1) and PtSn/C (3∶2), were prepared by chemical impregnation-reductio n method with formaldehyde as the reductant. DME electro-oxidation and adsorptio n at Pt electrode and Pt electro-catalysts were investigated by Cyclic Voltammet ry(CV), Quasi-steady state polarization and Gas Chromatography(GC). CV showed th at there were two current peaks of DME electro-oxidation at Pt electrode around 0.8V (vs RHE); DME was adsorbed at Pt electrode more weakly and slowly than oxyg en, methanol, even hydrogen; the onset potential of DME oxidation was 50mV less than that of methanol, and DME peak potential 110 mV lower, thus more advantageo us for using in fuel cells than methanol. GC showed that small amount of HCHO wa s generated during DME electro-oxidation. The mechanism of DME electro-oxidation was proposed. Among the three electro-catalysts (Pt/C, PtRu/C and PtSn/C), Pt a lloy catalysts, especially PtRu/C, showed a higher performance toward DME electr o-oxidation, as in the case of methanol. Temperature experiments showed that bot h DME electro-oxidation and adsorption on Pt and Pt alloy catalysts were favored with increased temperature.
文摘The performance of electrocatalytic oxygen reduction on Mo-Ru-X (X=S, Se, Te) was investigated. The catalysts were synthesized by the carbonyl complexes decomposition method. The activities of the catalysts were measured by potentiodynamic and AC impedance. The micro-structures and compositions were characterized by XRD, TEM and EDS. Transmission electron microscopy (TEM) measurements reveal that the catalyst material is of amorphous Ru cluster chalcogenides in the nanoscale range. The electrochemical experiments show that the activity of Mo-Ru-Se is the highest, and peak current density is 3.32 mA·cm-2. However, Mo-Ru-Se is sensitive to methanol in methanol-containing electrolyte, and the activity decreased with the increasing of methanol concentration. The activity of Mo-Ru-S is poorer than Mo-Ru-Se, the peak current density is 2.80 mA·cm-2, the behavior of methanol effect on the activity is similar to Mo-Ru-Se. The tolerant-methanol performance of Mo-Ru-Te is the best in the three, but activity is not high, peak current density is 2.69 mA·cm-2 only.
