2D Trimetal-organic framework derived metal carbon hybrid catalyst for urea electro-oxidation and 4-nitrophenol reduction
Yun, Sivalingam Gopi, Silambarasan Perumal, Ebtesam M. Al Olayan, Ohoud D. AlAmri, Abeer S. Aloufi, Murugavel Kathiresan, Kyusik . 2021
Because of the abundance of transition metals, their enhanced electrochemical/chemical efficiency onpar with the benchmark catalysts, long-term stability, etc., the expansion of transition metal/metaloxide-based electrocatalysts for oxygen evolution, urea oxidation reactions and 4-nitrophenol reductionbecomes indispensable. In particular, the abundant availability along with improved electrochemicalperformance is crucial for fuel cell applications when it comes to large scale commercialization. In thiswork, we report the synthesis of a trimetallic metal-organic framework based on Ni, Co and Zn using BTCas a linker and the preparation of its metal oxide - carbon composites at different temperatures, 600, 700and 800C (TM-MOF-600, TM-MOF-700, and TM-MOF-800) by carbonization under an inert atmo-sphere. The PXRD pattern of TM-MOF complemented well with the simulated XRD patterns of CoeNi-BTC MOF as well as Zn-BTC MOF, whereas the PXRD pattern of the carbonized samples indicated thepresence of three types of metal oxides i.e., CoO, NiO, and ZnO. TEM indicated spherical morphology ofTM-MOF, upon calcination, an irregular agglomeration occurred and the average particle size was foundto be 60e110 nm. The as-prepared TM-MOF and its carbon composites were tested for their electro-catalytic as well as catalytic activities towards oxygen evolution, urea oxidation and 4-nitrophenolreduction reactions. Electrochemical results indicate the better performance of TM-MOF-800 in both OER and UOR reactions with an onset potential of 1.66 V (OER) and 1.37 V (UOR) at a current density of10 mA cm2. The long-term stability of these catalysts under alkaline conditions indicates excellentstability. Besides, the urea electrolyzed products were analyzed by gas chromatography to get clear in-sights on the formed products. Catalytic reduction of 4-nitrophenol in the presence of excess NaBH4showed excellent conversion to 4-amino phenol in short duration.
Mannan oligosaccharide is one of the major components of the yeast cell wall. In the present study, the produc- tion, characterization, and bioactivity of yeast mannan were investigated.
Background Rodentolepis nana (syn. Hymenolepis nana), the most common cyclophyllid tapeworm infecting rodents, is a well-studied gastrointestinal parasite in mice and belongs to the family…