Potential of papaya seeds as a heterogenous catalyst in biodiesel synthesis

A biomass based low-cost catalyst production has been attempted. This study evaluated papaya seeds as the catalyst precursor for biodiesel synthesis. Dried papaya seed powder was calcined at 500°C for 3 hours to produce papaya seed ash. Then, papaya seed ash was applied as catalyst for transesterification of palm oil and methanol. Catalyst load and reaction time was varied. Papaya seed ash was analyzed by SEM-EDX and biodiesel physical properties was analyzed according to the European standards (EN 14214). SEM-EDX results indicated that papaya seed ash contains a number of minerals such as K2O, MgO and CaO which can function as catalysts in biodiesel synthesis. The produced biodiesel also met European standards. Highest biodiesel yield of 95.6% was obtained for reaction temperature of 60°C, reaction time of 2 hours, catalyst load of 2%, methanol to oil ratio of 12:1. Preliminary research revealed that PSA may be applied as a catalyst in biodiesel synthesis.

Catalysts Containing Transition Metals on Nitrogen and Carbon Structures for Hydrogen Production through Saltwater Electrolysis

When hydrogen is produced by electrolysis the possibility of water stress in some populations and scarcity of precious metals for catalyst production are seen as future barriers. The use of non-precious metal catalysts allied to direct saltwater splitting reduce the pressure on scarce resources. Here, four Metal-Nitrogen-Carbon (M-N-C) catalysts were synthesized with metal salts of Co, Fe, Ni and FeNi, with 1,5-diaminonhaptalene as N-C source. These catalysts were compared with a blank N-C without metal and a Pt/C commercial catalyst. Tests were conducted in electrolyte solution 0.5 M of H2SO4 and 0.5 M of NaCl. Results showed limited activity towards Hydrogen Evolution Reaction (HER) compared with Pt/C and other non precious metal catalysts. Nevertheless, points out trends for better catalyst synthesis as improved activity of FeNi catalyst in acidic media and saltwater.

Recent Advances in Producing Sugar Alcohols and Functional Sugars by Engineering Yarrowia lipolytica

The sugar alcohols and functional sugars have wide applications in food, pharmaceutical, and chemical industries. However, the smaller quantities of natural occurring sugar alcohols and functional sugars restricted their applications. The enzymatic and whole-cell catalyst production is emerging as the predominant alternatives. The properties of Yarrowia lipolytica make it a promising sugar alcohol and functional sugar producer. However, there are still some issues to be resolved. As there exist reviews about the chemical structures, physicochemical properties, biological functions, applications, and biosynthesis of sugar alcohols and/or functional sugars in Y. lipolytica, this mini review will not only update the recent advances in enzymatic and microbial production of sugar alcohols (erythritol, D-threitol, and xylitol) and functional sugars (isomaltulose, trehalose, fructo-oligosaccharides, and galacto-oligosaccharides) by using recombinant Y. lipolytica but also focus on the studies of gene discovery, pathway engineering, expanding substrate scope, bioprocess engineering, and novel breeding methods to resolve the aforementioned issues.

Precise Catalyst Production for Carbon Nanotube Synthesis with Targeted Structure Enrichment

The direct growth of single-walled carbon nanotubes (SWCNTs) with a narrow distribution of diameter or chirality remains elusive despite significant benefits in properties and applications. Nanoparticle catalysts are vital for SWCNT synthesis, but how to precisely manipulate their chemistry, size, concentration, and deposition remains difficult, especially within a continuous production process from the gas phase. Here, we demonstrate the preparation of W6Co7 alloyed nanoparticle catalysts with precisely tunable stoichiometry using electrospray, which remain solid state during SWCNT growth. We also demonstrate continuous production of liquid iron nanoparticles with in-line size selection. With the precise size manipulation of catalysts in the range of 1–5 nm, and a nearly monodisperse distribution (σg < 1.2), an excellent size selection of SWCNTs can be achieved. All of the presented techniques show great potential to facilitate the realization of single-chirality SWCNTs production.

Precise Catalyst Production for Carbon Nanotube Synthesis with Targeted Structure Enrichment

The direct growth of single-walled carbon nanotubes (SWCNTs) with a narrow distribution of diameter or chirality remains elusive despite significant benefits in properties and applications. Nanoparticle catalysts are vital for SWCNT synthesis, but how to precisely manipulate their chemistry, size, concentration, and deposition remains difficult, especially within a continuous production process from the gas-phase. Here, we demonstrate the preparation of W6Co7 alloyed nanoparticle catalysts with precisely tunable stoichiometry using electrospray, which remain solid state during SWCNT growth. We also demonstrate continuous production of liquid iron nanoparticles with in-line size selection. With the precise size manipulation of catalysts in the range of 1-5 nm, and a nearly monodisperse distribution (&sigma;g &lt; 1.2), an excellent size selection of SWCNT can be achieved. All of the presented techniques show great potential to facilitate the realization of single-chirality SWCNT production.

Precise Catalyst Production for Carbon Nanotube Synthesis with Targeted Structure Enrichment

The direct growth of single-walled carbon nanotubes (SWCNTs) with a narrow distribution of diameter or chirality remains elusive despite significant benefits in properties and applications. Nanoparticle catalysts are vital for SWCNT synthesis, but how to precisely manipulate their chemistry, size, concentration, and deposition remains difficult, especially within a continuous production process from the gas-phase. Here, we demonstrate the preparation of W6Co7 alloyed nanoparticle catalysts with precisely tunable stoichiometry using electrospray, which remain solid state during SWCNT growth. We also demonstrate continuous production of liquid iron nanoparticles with in-line size selection. With the precise size manipulation of catalysts in the range of 1-5 nm, and a nearly monodisperse distribution (&sigma;_g &lt; 1.2), an excellent size selection of SWCNT can be achieved. All of the presented techniques show great potential to facilitate the realization of single-chirality SWCNT production.