Urea Photosynthesis inside Polyelectrolyte Capsules:  Effect of Confined Media

Abstract

The influence of the restricted volume of poly(styrene sulfonate)/poly(allylamine hydrochloride) capsules of different size (2.2, 4.2, and 8.1 microm) on the TiO2-assisted photosynthesis of urea from inorganic precursors (CO2 and NO(3-)) in aqueous solution was demonstrated. Poly(vinyl alcohol) was employed as electron donor to facilitate the photosynthetic process. Decreasing the size of the confined microvolume of polyelectrolyte capsules accelerates the NO(3-) photoreduction, which is a limiting stage of the urea photosynthesis and, correspondingly, increases the efficiency of urea production. The highest yield of urea photosynthesis (37%) was achieved for Cu-modified TiO2 nanoparticles encapsulated inside 2.2 microm poly(styrene sulfonate)/poly(allylamine hydrochloride) capsules.

A surface science perspective on TiO2 photocatalysis

“…Papers are emerging in the field which have examined specialized synthetic processes using TiO 2 as a photocatalyst. Examples include selective formation of certain biomolecules [1815][1816][1817], carbemide formation [1818], Cl 2 production [1819], cross-linking in fibers [1820,1821], epoxidation and selective oxidation reactions [926,929,1021,1598,[1822][1823][1824][1825][1826][1827], ozone formation [1828], hydrogen peroxide production [1486,1829,1830], selective isomerization reactions [986], nitro group addition [1831,1832], polymerization processes [1833][1834][1835][1836], urea formation [1837,1838] and a variety of other miscellaneous processes [925,1368,[1839][1840][1841][1842][1843][1844][1845][1846]. The photooxidation of alkenes to generate epoxides has been explored in the cases of several molecules, including 1-hexene [1823], 1-decene: [1823,1...…”

Facile method for preparing organic/inorganic hybrid capsules using amino-functional silane coupling agent in aqueous media

“…Utilization of spatially confined microenvironment formed by microcapsules is of great interest for design of effective microreactors for various reactions such as nanoparticle synthesis [1], photosynthesis [2] and biosynthesis [3]. Many techniques for preparing microcapsules have been developed using a variety of organic polymers including polyelectrolytes [4,5], synthetic polymers [6,7] and polypeptides [8,9] because these polymer characteristics dominate capsule properties such as capsule size, shell thickness, permeability and rigidity.…”

Scalable Synthesis of Chestnut‐ Bur‐like Magnetic Capsules Loaded with Size‐Controlled Mono‐ or Bimetallic Cores

“…[1,2] If such a capsule reactor is given an inside core, referred to as a core/shell capsule, it is possible that novel properties could be conferred on the resulting capsule, based on the nature of the core material. Such hollow capsules functionalized with movable cores have novel properties and have been explored by several groups.…”

“…The composition of the bimetallic core in the hematite shell was controlled by varying the reaction order and concentrations of metal precursors. The order of synthesis of metal Nps within the PEMPRs is denoted as (1), (2), and (3) (see Table 1). …”