Effects of varying amounts of Na on Pd/TiO2 for the direct synthesis of H2O2: Identification of the Pd dispersion and catalytic activity enhancement by changing the surface electronic states

Title
Effects of varying amounts of Na on Pd/TiO2 for the direct synthesis of H2O2: Identification of the Pd dispersion and catalytic activity enhancement by changing the surface electronic states
Authors
한상수Young-Hoon ChoGeun-Ho HanMyung-gi SeoKwan-Young Lee
Keywords
Palladium; Sodium addition; Alkali metal; Highly Pd dispersion; Titanium dioxide; Direct synthesis of hydrogen peroxide
Issue Date
2020-03
Publisher
Molecular catalysis
Citation
VOL 484, 110732
Abstract
Alkali elements have been applied as promoters of noble metals (e.g., Pd or Pt) to enhance their catalytic activities by changing the surface electronic states of the noble metals. In particular, the role of alkali elements is to improve the dispersion properties of the active metal. In this study, various amounts of the alkali element sodium (Na) were used as a promoter for a Pd/TiO2 catalyst. Importantly, the catalysts were synthesized to improve the selectivity and production rate of the direct synthesis of hydrogen peroxide (DSHP) by increasing the Pd dispersion and surface area by changing the surface electronic properties. After the addition of Na onto Pd/TiO2, the H2O2 production rates were generally higher than those for pure Pd/TiO2 due to the synergistic effects between the Pd and Na on the TiO2 support. Particularly, among the tested catalysts, the 0.5  wt.% Na-promoted Pd/TiO2 (PdNa(0.6)/TiO2) catalyst exhibited the highest H2 conversion rate (22 %) in the iso-Pd weight and the highest H2O2 selectivity (95.4 %) and production rate (785.9  mmol/gPdh) for the iso-H2 conversion test. Na provides electrons to the Pd species, leading to a change in the Pd dispersion. Furthermore, the surface electronic state of Pd changed with increasing amounts of Na, and thus, heavily influenced the H2O2 selectivity. Ultimately, PdNa(0.6)/TiO2 achieved the best selectivity as a H2O2 producing catalyst in this study.
URI
http://pubs.kist.re.kr/handle/201004/72661
ISSN
2468-8231
Appears in Collections:
KIST Publication > Article
Files in This Item:
There are no files associated with this item.
Export
RIS (EndNote)
XLS (Excel)
XML


qrcode

Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.

BROWSE