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Water-gas shift (WGS) reaction is an important process for industrial hydrogen production. The side reaction of methanation often causes unavoidable loss of H2 along with this reaction. Here, we report a Rh1/TiO2 single-atom catalyst (SAC) with appreciable loading of 0.37 wt %, which exhibited an overall CO conversion of ∼95% but without any methanation at 300°C, even under CO2- and H2-rich WGS stream. The specific activity of this SAC was around four times higher than that of cluster catalyst, which meanwhile suffered from unfavorable methanation. It was found that Rh single atoms promoted the formation of more oxygen vacancies on the TiO2 support to activate H2O to generate H2 and prohibited the dissociation of H2 compared with Rh clusters, leading to the enhanced activity and selectivity for WGS. © 2016 American Institute of Chemical Engineers AIChE J, 63: 2081-2088, 2017 [ABSTRACT FROM AUTHOR]

Layered double hydroxides (LDHs) are promising materials for the preparation of novel drug delivery matrices. To reveal the interaction between LDHs and polymers, a series of pH‐sensitive sodium alginate/layered double hydroxides (SA/LDHs) hybrid beads were prepared using the simple surface crosslinking method. The SA/LDHs hybrid beads were characterized by FTIR, XRD, and SEM to study their structure and the role that LDHs play. Swelling behaviors in various aqueous solutions and drug loading as well as controlled release behavior of the SA/LDHs hybrid beads were also investigated by using diclofenac sodium (DS) as the model drug to reveal the effects of introduced LDHs. The results indicate that the positively charged LDHs layers are adsorbed on the negatively charged SA polymer chains through electrostatic interaction and act as inorganic crosslinkers in the three‐dimensional network. In addition, a small part of DS molecules intercalate into layers of LDHs through an anion exchange process. The electrostatic interaction between LDHs and SA has restricted movability of the SA polymer chains, and then slows down swelling and dissolution rates of the SA/LDHs hybrid beads in aqueous solutions. The electrostatic interaction and the intercalation of DS into layers of LDHs have also improved the entrapment efficiency (EE) and controlled release behavior of SA/LDHs hybrid beads for DS. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 2010 [ABSTRACT FROM AUTHOR]

The aim of the present work was to investigate the swelling behavior and in vitro release of nifedipine from alginate–chitosan hydrogel beads. Structure and surface morphology of the hydrogel were characterized by FTIR and SEM, respectively. Alginate–chitosan mixed beads and alginate–chitosan coated beads were prepared by ionic gelation method. The swelling ability of the beads and in vitro release of nifedipine in simulated gastric fluid (pH 1.5) and different phosphate buffer solutions (pH 2.5, 5.0, 6.8, 7.4, and 8.0) were found to be dependent on the presence of the polyelectrolyte complex between chitosan and alginate. The amount of nifedipine released from the mixed beads at pH 1.5 was relatively low (42%), whereas this value approached to 99% at pH 6.8. In comparison with the mixed beads, the released nifedipine from the coated beads was minimal at pH 1.5 (18%), whereas ∼99% nifedipine was released at pH 6.8. The results suggested that the coated beads can hold drug better at low pH than the mixed beads and show excellent pH sensitivity. Therefore, the alginate–chitosan coated beads could be a suitable polymeric carrier for drug delivery in the intestinal tract. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2008 [ABSTRACT FROM AUTHOR]