RSC Advances
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2019
·Vol. 9
·期 72
·42236-42244
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IF 3.049
Limeng Yang,Zhigang Shao
The development of low-cost, efficient and stable electrocatalysts for the oxygen reduction reaction (ORR) is desirable but remains a great challenge. We report a convenient and efficient synthesis approach of highly dispersed Fe–Nx catalysts for ORR. Typically, Fe–Zn-ZIF (zeolitic imidazolate frameworks) nanocrystals cast as precursor and graphene as supports, highly dispersed Fe–Nx species were fabricated with PVP (polyvinyl pyrrolidone) as surfactant via pyrolysis. With the help of graphene and surfactant, the agglomeration of iron particles has been avoided during pyrolysis, and the size and morphology of ZIF particles intercalating into the graphene layers can be regulated precisely as well. The amount of Fe–Nx active sites in C-rGO-ZIF catalyst arrived 4.29%, which is obviously higher than most monodispersed non-precious metal catalysts reported. The obtained C-rGO-ZIF catalyst exhibits a high onset potential of 0.89 V and a half-wave potential of 0.77 V, which is only 30 mV away from Pt/C in acidic media. The active sites of the catalyst was characterized and found to be the highly dispersed Fe–Nx species, large and accessible specific surface area of graphene and abundant active nitrogen atoms. When the C-rGO-ZIF catalyst was applied in the cathode of fuel cell, the power density can reach up to 301 mW cm−2, which highlights a practical application potential on small power supplies.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ChemPlusChem
·
2025
·
IF 2.8
Chunqiu Zhao,Qiang Chang,Fu Yin,Guowei Niu,Chenghua Zhang,Dan Liu,Bhekie B. Mamba,Alex T. Kuvarega
Graphical To enhance the catalytic performance of Zn−NC in the hydrogenation of CO to dimethyl ether, highly dispersed bimetallic catalysts are synthesized through the pyrolysis different metal-doped ZIF. The incorporation of secondary metals (Mn, Fe, Co, Ni, Cu) leads to distinct variations in catalytic performance. Among them, the introduction of Cu significantly improves catalytic activity. Highly dispersed bimetallic atomic-scale catalysts have garnered significant attention in syngas conversion filed due to the synergistic effects of the precisely structured bimetallic site, which facilitate the effective activation of CO. Despite their potential, synthesizing these catalysts to meet the specific application requirements remains challenging. Herein, various bimetallic catalysts were synthesized through the pyrolysis of the bimetallic ZIF precursors which were prepared by in situ doping of different metals (Mn, Fe, Co, Ni and Cu) into the ZIF-8 structure. In the presence of a highly dispersed and highly loaded Zn, the doping content in the ultimate second metallic catalysts varied between 0.15–1.20 wt % for different metals. The catalysts were systematically characterized using XRD, BET, TEM, XPS, Raman, ICP, and H 2 -TPD techniques. Among them, the Zn−NC regulated with Cu or Ni exhibited superior catalytic performance. Notably, the Cu−Zn−NC catalyst showed the highest activity, achieving a CO conversion of 32.8 % and optimal DME selectivity approaching 95.2 % in CO hydrogenation reactions. These enhanced performance metrics were attributed to the synergetic effects of bimetallic components. The incorporation of Cu not only preserved the original Zn−N structure but also preserved the catalytic performance unchanged. This preparation strategy is expected to filter out new research targets to use in diverse catalytic applications.
研究领域:
催化化学
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材料科学
·
能源化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2019
·
IF 14.229
Lijun Yang,Lei Zhang
Cost-effective transition metal-carbon-based hybrids have been widely dedicated to water splitting. Herein, a new three dimensional N-enriched holey carbon layers encapsulated bimetallic phosphides (CoNiP@CN) was synthesized by in situ growth, pyrolysis and phosphorization of CoNi mixed zeolite imidazole frameworks (ZIFs)@ZIF-8 films on Ni foam. CoNiP@CN/NF exhibited smaller overpotentials, lower charge transfer resistance and considerable stability for electrocatalysis. The better performance was attributed to the high conductivity of bimetallic phosphides and N-doped porous carbon, the maximum utilization of active sites on 3D conductive substrate and the protection of bimetallic phosphides by N-doped carbon layers. As an integrated high-performance non-noble electrocatalyst for overall water splitting, the CoNiP@CN/NF requires only 1.59 V@30 mA cm −2 in alkaline solution, which is comparable to many other non-noble metal catalysts. This work highlights the construction highly efficient transition metal-carbon-based electrocatalyst derived from well-defined ZIF precursor, promoting the development of low-cost non-noble metal hybrids in energy chemistry.
研究领域:
材料科学
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电化学
·
能源化学
✓ 已验证
产品关联
DOI
高影响因子
Nano Research
·
2020
·Vol. 13
·期 9
·2420-2426
·
IF 8.183
Luo Ergui,Wang Chen,Li Yang,Wang Xian,Gong Liyuan,Zhao Tuo,Jin Zhao,Ge Junjie,Liu Changpeng,Xing Wei
Fe/N/C material is the most competitive alternative to precious-metal catalysts for oxygen reduction. In view of the present consensus on active centers, further effort is directed at maximizing the density of single Fe atoms. Here, the imperfections in commonly used doping strategy of Fe for the synthesis of zeolitic imidazolateframework (ZIF)-derived Fe/N/C catalysts are revealed. More importantly, a strikingly improved catalyst is obtained by a ‘second pyrolysis’ method and delivers a half-wave potential of 0.825 V (vs. RHE) in acidic media. The strong confinement effect of carbonaceous host accounts for the formation of dense single-atom sites and thus the high activity. Our findings will potentially facilitate future improvement of M/N/C catalysts.
研究领域:
材料科学
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催化化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2023
·
IF 9.9
Hao Xu,Lihui Xiao,Peixia Yang,Xiangyu Lu,Lilai Liu,Dan Wang,Jinqiu Zhang,Maozhong An
Zeolitic imidazole framework (ZIF)-derived iron–nitrogen-carbon (Fe N C) materials are expected to be high-efficiency catalysts for oxygen reduction reaction (ORR). However, increasing the density of active sites while avoiding metal accumulation still faces significant challenges. Herein, solvent environment engineering is used to synthesize the Fe N C containing dense Fe-N x moieties by adjusting the solvent during the ZIF precursor synthesis process. Compared with methanol and water/methanol, the aqueous media can provide a more moderate Fe content for the ZIF precursor, which facilitates the construction of high-density Fe-N x sites and prevent the appearance of iron-based nanoparticles during pyrolysis. Therefore, the Fe N C(C) nanocubes synthesized in an aqueous media have the highest single atom Fe loading (0.6 at%) among the prepared samples, which presents excellent oxygen reduction properties and durability under alkaline and acidic conditions. The advantage of Fe N C(C) is proven in Zn-air batteries, with outstanding performance and long-term stability.
研究领域:
材料科学
·
电化学
·
能源科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
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