CHEMICAL ENGINEERING JOURNAL
·
2017
·
IF 6.216
Lu Lin,Haiou Liu,Xiongfu Zhang
MOFs-based yolk-shell composites are newly-presented but promising catalysts in the area of catalysis. In this work, a kind of unique rattle-type Pd/ZnO@hollow ZIF-8 yolk-shell catalyst is developed via a ZnO-template approach, in which there exist two processes of both ZnO-induced ZIF-8 formation and ZnO dissolution. Of prime importance is that ZnO was selected as the sacrificial template since it can not only be etched in the solution of ligands but also assist the formation of compact ZIF-8 shell by providing nucleation sites via linker activation. It is also proposed that sufficient amount of Zn(NO 3 ) 2 ·6H 2 O and 2-methylimidazole added in the growth solution of ZIF-8 should accelerate the outward growth of ZIF-8 layer as well as dissolution of ZnO. This way, the final construction of Pd/ZnO@hollow ZIF-8 yolk-shell materials is achieved. Compared to the Pd/ZnO counterparts, Pd/ZnO@hollow ZIF-8 rattle-type catalysts demonstrate a promoted behavior in terms of size-selectivity for the liquid hydrogenations of alkenes due to the outer ZIF-8 shell acting as a molecular sieve. It can also protect the catalytically active Pd NPs from poisoning and leaching, giving rise to an excellent stability. Moreover, the yolk-shell catalysts manifest a better activity beyond their core-shell counterparts since the presented interior hollow space between core and shell is likely to expose more active surfaces to reactants.
研究领域:
催化化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
DALTON TRANSACTIONS
·
2024
·
IF 3.5
Guandong Wang,Yizhi Yin,chenfeng Lin,Shixiong Min,Jinfu Ma
In pursuit of highly active zinc-air battery (ZAB) catalysts, nitrogen doping has proven key to enhancing carbon-based non-metallic catalysts' performance in the oxygen reduction reaction (ORR). This study employed a novel method to synthesize variously sized ZnO materials coated with ZIF-8. Notably, smaller particle sizes correlated with reduced activation energy. ZnO-12, the smallest variant, fully carbonized at 800°C, resulting in zinc ion evaporation and the formation of an amorphous carbon nano-hollow structure, ZIF8/ZnO-12. This material showcased remarkable ORR properties, with an onset potential of 0.9 V (vs. RHE) and a Tafel slope of 71.4 mV dec-1, surpassing the benchmark Pt/C catalyst and exhibiting excellent stability. Moreover, in ZAB tests, ZIF8/ZnO-12 achieved a specific capacity of 816 mAh g-1, outperforming Pt/C. DFT calculations indicate that under alkaline conditions, nitrogen-doped carbon materials containing adsorbed oxygen and doped oxygen exhibit lower catalytic activation energy for the ORR, which is beneficial for accelerating the ORR. This research provides valuable insights into designing more efficient carbon-based non-metallic catalysts for ZABs.
研究领域:
材料科学
·
电化学
·
催化科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
MICROPOROUS AND MESOPOROUS MATERIALS
·
2016
·
IF 3.349
Xiaojun He,Zide Liu,Hao Ma,Nan Zhang,Moxin Yu,Mingbo Wu
Shell-like hierarchical porous carbons (SHPCs) were prepared from petroleum pitch by a nano-ZnO-template strategy coupled with in-situ KOH activation technique. The as-made SHPCs feature interconnected thin carbon shells and abundant short hierarchical pores, which are favorable for both the rapid transfer of electrons and ions during the charge-discharge process. The SHPCs made under optimal conditions show a specific surface area up to 2646 m 2 g −1 . As electrodes for supercapacitors , SHPCs exhibit a high specific capacitance up to 296 F g −1 at 0.05 A g −1 in 6 M KOH electrolyte, good rate performance remaining at 237 F g −1 at 20 A g −1 and a good cycle stability with over 96.5% capacitance retention after 5000 cycles. This work suggests a facile strategy for high-efficiency synthesis of SHPCs from petroleum pitch as electrode materials for supercapacitors and other energy stotage devices.
研究领域:
材料科学
·
能源存储技术
✓ 已验证
DOI
高影响因子
JOURNAL OF POWER SOURCES
·
2016
·
IF 6.333
Xiaojun He,Xiaojing Li,Hao Ma,Jiufeng Han,Hao Zhang,Chang Yu,Nan Xiao,Jieshan Qiu
3D interconnected graphene nanocapsules (GNCs) were prepared from diverse aromatic hydrocarbons by a nano-ZnO-template strategy coupled with in-situ KOH activation technique. The as-made graphene networks feature thin carbonaceous shells with well-balanced micropores and mesopores. Such 3D porous networks provide freeways for good electron conduction , short pores for ion fast transport, and abundant micropores for ion adsorption. As the electrodes in supercapacitors , the unique 3D GNCs show a high capacitance of 277 F g −1 at 0.05 A g −1 , a good rate performance of 194 F g −1 at 20 A g −1 , and an excellent cycle stability with over 97.4% capacitance retention after 15000 cycles in 6 M KOH electrolyte. This synthesis strategy paves a universal way for mass production of 3D graphene materials from diverse aromatic hydrocarbon sources including coal tar pitch and petroleum pitch for high performance supercapacitors as well as support and sorbent .
研究领域:
材料科学
·
能源存储与转换
✓ 已验证
DOI
高影响因子
CHEMISTRY-A EUROPEAN JOURNAL
·
2019
·Vol. 26
·期 6
·1306-1313
·
IF 5.16
Muhammad Sohail Riaz,Siwei Zhao,Chenlong Dong,Shuying Nong,Yantao Zhao,Muhammad Javed Iqbal,Fuqiang Huang
Graphical Selenized and phosphorized cobalt-nickel oxide microcubes formed by a novel strategy using a sacrificial ZnO spherical template are employed as an oxygen evolution reaction (OER) electrocatalyst. The selenized samples manifest desirable and robust OER performance, with comparable overpotential at 10 mA cm −2 (312 mV) as RuO 2 (308 mV) and better activity when the current reaches 13.7 mA cm −2 . Oxygen electrocatalysis is of remarkable significance for electrochemical energy storage and conversion technologies, together with fuel cells, metal-air batteries, and water splitting devices. Substituting noble metal-based electrocatalysts by decidedly effective and low-cost metal-based oxygen electrocatalysts is imperative for the commercial application of these technologies. Herein, a novel strategy is presented to fabricate selenized and phosphorized porous cobalt-nickel oxide microcubes by using a sacrificial ZnO spherical template and the resulting microcubes are employed as an oxygen evolution reaction (OER) electrocatalyst. The selenized samples manifest desirable and robust OER performance, with comparable overpotential at 10 mA cm −2 (312 mV) as RuO 2 (308 mV) and better activity when the current reaches 13.7 mA cm −2 . The phosphorized samples exhibit core–shell structure with low-crystalline oxides inside amorphous phosphides, which ensures superior activity than RuO 2 with the same overpotential (at 10 mA cm −2 ) yet lower Tafel slope. Such a surface doping method possibly will provide inspiration for engineering electrocatalysts applied in water oxidation.
研究领域:
材料科学
·
电化学
·
能源存储与转换
·
催化
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）