SiO2-Modified Pt/Al2O3 for Oxidative Dehydrogenation of Ethane: A Preparation Method for Improved Catalytic Stability, Ethylene Selectivity, and Coking Resistance

The Cooperation of Pd center and Lewis Acid Sites to Achieve High Selectivity Towards Kinetic Carbonate Product for Oxidative Carbonylation Reaction

Dimethyl carbonate and dimethyl oxalate are competitive products of the carbonylation reaction of methyl nitrite (MN) under Pd-based catalysts. The chemo-selectivity is influenced not just by the thermodynamic constraints of reaction conditions but also by the electronic structures of catalysts. Lewis acid sites are extensively employed to modulate the electronic structures of Pd active sites for kinetic carbonate production, but their precise role remains unclear. Herein, we employed a combination of reaction kinetic, in situ DRIFTS experiments and DFT calculation, unveiling the indispensable role of Lewis acid sites in activating MN and facilitating the transfer of *OCH3 species, which is the key to obtain the kinetic carbonate outcome. The molecular understanding reveals the cooperation of Pd center and Lewis acid sites in directing selectivity towards carbonate product, which enables the rational design of higher-performance catalysts.

Oxidative Dehydrogenation of Ethane with CO2 over Mo/LDO Catalyst: The Active Species of Mo Controlled by LDO

A series of the layered double oxides supported molybdenum oxide catalysts were synthesized and evaluated in the oxidative dehydrogenation of ethane with CO2 (CO2-ODHE). The 22.3 wt% Mo/LDO catalyst delivered a 92.3%selectivity to ethylene and a 7.9% ethane conversion at relatively low temperatures. The molybdenum oxide catalysts were fully characterized by XRD, BET, SEM, TEM, UV–vis, Raman TG, and XPS. Isolated [MoO4]2− dominated on the surface of the fresh 12.5 wt% Mo/LDO catalyst. With the increase of the Mo content, the Mo species transformed from [MoO4]2− to [Mo7O24]6− and [Mo8O26]4− on the 22.3 wt% and 30.1 wt% Mo/LDO catalysts, respectively. The redox mechanism was proposed and three Mo species including [MoO4]2−, [Mo7O24]6−, and [Mo8O26]4− showed quite different functions in the CO2-ODHE reaction: [MoO4]2−, with tetrahedral structure, preferred the non-selective pathway; [Mo7O24]6−, with an octahedral construction, promoted the selective pathway; and the existence of [Mo8O26]4− reduced the ability to activate ethane. This work provides detailed insights to further understand the relationship between structure–activity and the role of surface Mo species as well as their aggregation state in CO2-ODHE.

Supported Pt-Cu bimetallic catalysts: preparation and synergic effects in their catalytic oxidative degradation of aniline

Catalytic Fenton oxidation is an effective way to remove organic pollutants in water, and the performance of the catalyst is a key issue for the competiveness of this method. In this work, various supported bimetallic Pt–Cu catalysts were prepared by different impregnation methods and their performances for catalytic Fenton oxidation of aniline in water were investigated. In the different impregnation methods employed, factors including the reduction method of the metal precursor, type of catalytic support, and loading of metal were investigated. The effect of different reduction methods on actual loadings of the active components on the supported Pt–Cu catalysts showed the order of (i) H₂ reduction > (ii) liquid phase methanal reduction. Meanwhile, compared with the monometallic catalysts, the Pt–Cu alloy phase (mainly in the form of PtCu₃) was generated and the specific surface area was significantly reduced for the bimetallic catalysts. In the process of Fenton catalytic oxidation of aniline, it was found that most of the prepared catalysts had a certain catalytic activity for H₂O₂ accompanied with aniline degradation. It was found that Pt_0.5Cu_1.5/AC (where AC denotes activated carbon) exhibited superb catalytic activity compared with all other prepared catalysts. In particular, aniline was almost completely mineralized in a neutral solution (500 mg L⁻¹ aniline, 0.098 mol L⁻¹ H₂O₂) after 60 min at 50 °C using Pt–Cu/AC (Pt: 0.5%, Cu: 1.5%). The characterization results showed that the Pt and Cu components were rather evenly distributed on the AC support for this catalyst. More importantly, there was an obvious synergic effect on the supported bimetallic catalyst between the Pt and Cu components for the catalytic oxidation of aniline.

An AC supported Pt–Cu catalyst prepared with a new methanal reduction method was found to be quite effective for catalytic Fenton oxidation of aniline in water. The Pt and Cu components showed a synergic effect for the catalytic process.

Oxidative dehydrogenation of ethane: catalytic and mechanistic aspects and future trends

Ethane oxidative dehydrogenation (ODH) is an attractive, low energy, alternative route to reduce the carbon footprint for ethene production, however, the commercial implementation of ODH processes requires catalysts with improved selectivity.

Preparation, characterization and catalytic performance of rod-like Ni–Nb–O catalysts for the oxidative dehydrogenation of ethane at low temperature

Improved catalytic performance as well as stability over Ni–Nb–O catalysts by hydrothermal method.