Gold Nanoparticles on Nanosheets Derived from Layered Rare-Earth Hydroxides for Catalytic Glycerol-to-Lactic Acid Conversion

Abstract

Layered rare-earth hydroxides (LREHs), as a series of special lamellar compounds having a similar structure to layered double hydroxides (LDHs), are becoming a new type of catalyst materials. In this study, we have prepared a series of uniform LREH (RE = Y, La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, and Tm) nanosheets through a reverse-microemulsion method. After deposition–precipitation of HAuCl4 and calcination, supported Au catalysts (denoted as Au/LREO) were subsequently obtained. The catalytic properties of all the derived Au/LREO catalysts were evaluated by aerobic conversion of glycerol to lactic acid under mild conditions (90 °C, 1 atm). Among these catalysts, Au/LPrO displays the best performances, including the highest glycerol conversion, lactic acid, and C3 product selectivity. Both the catalytic activities and the characterizations of the structure of Au/LREO indicate that the kind of rare-earth ions plays a key role in determining the Au particle size and its valence state and reducibility, which are the important factors correlated with the catalytic activities in glycerol conversion. In fact, the three features of gold particles, the extra-small size (∼3 nm), high content of Au0 species, and high reducibility, are the essential prerequisites for achieving the superior catalytic performance of Au/LPrO.

Effect of Fe(III) Modification on the Phosphorus Removal Behavior of Ce(III) Carbonate Adsorbents

“…Wang et al utilized coprecipitation of iron oxide and ceria to improve the adsorption performance. Compared with cerium oxide, the layered structure of cerium carbonate possesses cerium active sites that are easily accessible for the phosphate adsorption process. Enhancement in the adsorption effect could be achieved by exploiting alternative doping elements …”

A review of the catalytic conversion of glycerol to lactic acid in the presence of aqueous base

“…Layered rare-earth hydroxide (LREH, RE = Y, La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, and Tm) nanosheets were used as supports for the gold(0) nanoparticles. 53 The LREH nanosheets supported gold(0) nanoparticles were prepared by the deposition–precipitation of HAuCl 4 and calcination and denoted as Au/LREO. The highest glycerol conversion (68.2%) with the highest LA selectivity (66.8%) was obtained using Au/LPrO among Au/LREO catalysts at 90 °C for 14 h under aerobic conditions.…”

Combined dehydrogenation of glycerol with catalytic transfer hydrogenation of H2 acceptors to chemicals: Opportunities and challenges

“…Furthermore, low reaction temperature can also significantly inhibit C–C bond cleavage by alkalis, thus good selectivity of C 3 products. Selective oxidation of glycerol to LA is generally carried out with the promotion of various noble metal and some non-noble metal catalysts (e.g., Au, Pt, Pd, and polyoxometalate ) ( Shen et al, 2010 ; Lakshmanan et al, 2013 ; Xu et al, 2013 ; Cho et al, 2014 ; Purushothaman et al, 2014 ; Zhang et al, 2016a ; Zhang et al, 2016b ; Arcanjo et al, 2017 ; Tao et al, 2017 ; Zhang et al, 2017 ; Douthwaite et al, 2020 ; Evans et al, 2020 ; Tao et al, 2020 ; Torres et al, 2021 ; Wang et al, 2021 ). In the first important advances, Shen et al (2010) reported that the bimetallic Au–Pt catalysts exhibit excellent performances with a high yield of 86% in the presence of alkali and O 2 at 90°C.…”