Au‐Promoted Pt nanoparticles supported on MgO / SBA ‐15 as an efficient catalyst for selective oxidation of glycerol

The Influence of Different Morphologies of Black TiO2 Supported Pt Catalysts on the Catalytic Oxidation of Glycerol

The increased production of biodiesel has resulted in a corresponding rise in glycerol (GLY) production. The glycerol oxidation reaction is characterized by mild reaction conditions and relatively simple products, making it a widely utilized method for glycerol conversion and one of the most promising industrial approaches. In this study, we prepared black titanium dioxide-supported platinum catalysts with different morphology. Different catalysts were synthesized by altering the morphology of the support and the reduction temperature of the support, which exhibited distinct activities and performance in the catalytic oxidation of glycerol to glyceric acid under alkali-free conditions. The evaluation of the catalysts revealed that when flaky black titanium dioxide (F-B-TiO2) is employed as a support, the catalyst Pt/F-B-TiO2 (600 °C), reduced at 600 °C, demonstrates the best catalytic performance. Characterization results indicate that the Ti3+ content in the flaky (F-B-TiO2) support is higher compared to other morphologies. Additionally, at a calcination temperature of 600 °C, the Pt° content is maximized among the synthesized catalysts. Based on the experimental and characterization results, the catalytic performance is collaboratively influenced by the presence of Ti3+ and Pt0.

Mechanistic Insights into Glycerol Oxidation to High-Value Chemicals via Metal-Based Catalysts

The oxidation of glycerol offers a valuable route for producing high-value chemicals. This review provides an in-depth analysis of the current advancements and mechanistic insights into novel metal-based catalysts for glycerol oxidation. We discuss the catalytic roles of both precious metals (e.g., Pt, Pd, Au), noted for their high efficiency and selectivity, and cost-effective alternatives, such as Ni, Cu, and Fe. Bimetallic and metal oxide catalysts are highlighted, emphasizing synergistic effects that enhance catalytic performance. This review elucidates the key mechanism involving selective adsorption and oxidation, providing detailed insights from advanced spectroscopic and computational studies into the activation of glycerol and stabilization of key intermediates, including glyceraldehyde and dihydroxyacetone. Additionally, selective carbon-carbon bond cleavage to yield smaller, valuable molecules is addressed. Finally, we outline future research directions, emphasizing the development of innovative catalysts, deeper mechanistic understanding, and sustainable process scale-up, ultimately advancing efficient, selective, and environmentally friendly catalytic systems for glycerol valorization.

Stable and Active Au Catalyst Supported on CeMnO3 Perovskite for Selective Oxidation of Glycerol

The selective oxidation of glycerol holds promise to transform glycerol into value-added chemicals. However, it remains a big challenge to achieve satisfactory selectivity toward the specific product at high conversion due to the multiple reaction pathways. Here, we prepare a hybrid catalyst via supporting Au nanoparticles on CeMnO₃ perovskite with a modest surface area, achieving promoted conversion of glycerol (90.1%) and selectivity of glyceric acid (78.5%), which are much higher than those of CeMnO_x solid-solution-supported Au catalysts with larger surface area and other Ce-based or Mn-based Au catalysts. The strong interaction between Au and CeMnO₃ perovskite facilitates the electron transfer from the B-site metal (Mn) in the CeMnO₃ perovskite to Au and stabilizes Au nanoparticles, which results in the enhanced catalytic activity and stability for glycerol oxidation. Valence band photoemission spectral analysis reveals that the uplifted d-band center of Au/CeMnO₃ promotes the adsorption of the glyceraldehyde intermediate on the catalyst surface, which benefits further oxidation of glyceraldehyde into glyceric acid. The flexibility of the perovskite support provides a promising strategy for the rational design of high-performance glycerol oxidation catalysts.

Single Metal Atoms Embedded in the Surface of Pt Nanocatalysts: The Effect of Temperature and Hydrogen Pressure

Embedding energetically stable single metal atoms in the surface of Pt nanocatalysts exposed to varied temperature (T) and hydrogen pressure (P) could open up new possibilities in selective and dynamical engineering of alloyed Pt catalysts, particularly interesting for hydrogenation reactions. In this work, an environmental segregation energy model is developed to predict the stability and the surface composition evolution of 24 Metal M-promoted Pt surfaces (with M: Cu, Ag, Au, Ni, Pd, Co, Rh and Ir) under varied T and P. Counterintuitive to expectations, the results show that the more reactive alloy component (i.e., the one forming the strongest chemical bond with the hydrogen) is not the one that segregates to the surface. Moreover, using DFT-based Multi-Scaled Reconstruction (MSR) method and by extrapolation of M-promoted Pt nanoparticles (NPs), the shape dynamics of M-Pt are investigated under the same ranges of T and P. The results show that under low hydrogen pressure and high temperature ranges, Ag and Au—single atoms (and Cu to a less extent) are energetically stable on the surface of truncated octahedral and/or cuboctahedral shaped NPs. This indicated that coinage single-atoms might be used to tune the catalytic properties of Pt surface under hydrogen media. In contrast, bulk stability within wide range of temperature and pressure is predicted for all other M-single atoms, which might act as bulk promoters. This work provides insightful guides and understandings of M-promoted Pt NPs by predicting both the evolution of the shape and the surface compositions under reaction gas condition.