Ru-based core-shell catalyst and its preparation method and use in methane oxidation reforming preparation of synthetic gas

Abstract

The invention discloses a catalyst for methane partial-oxidation preparation of synthetic gas. Ruthenium oxide or nickel-ruthenium oxide nanoparticles are synthesized and then are coated with SiO2 so that a core-shell structure is formed, and the core-shell structure undergoes in-situ reduction so that ruthenium oxide or nickel-ruthenium oxide core particles are reduced into metal ruthenium or nickel-ruthenium dimetal and a core-shell metal catalyst with a microcapsule structure is obtained. The microcapsule structure is conducive to reactant molecule enrichment, adsorption on the catalyst surface and activation. The catalyst is used for methane partial-oxidation preparation of synthetic gas, has high catalyst activity, a methane conversion rate greater than 95%, CO / H2 selectivity greater than 90% or a methane conversion rate greater than 90%, and CO / H2 selectivity greater than 95%. After consecutive reaction for 10 days, a conversion rate and selectivity are not reduced and thus the catalyst for the object reaction has high efficiency and good stability. The invention discloses a preparation method of the Ru-based core-shell catalyst.

Description

technical field [0001] The invention relates to a Ru-based core-shell structure catalyst and its application in methane oxidation reforming to produce synthesis gas. Background technique [0002] The production and application of syngas plays an extremely important role in the chemical industry. As an important chemical raw material, it can be used to produce chemicals such as methanol, formic acid, liquid fuel, and dimethyl ether. Methanol produced from synthesis gas is a very important large-tonnage organic chemical product. Since the rise of oil prices in the 1970s, the concept of carbon-chemistry has been proposed. It can be said that syngas is an important raw material to replace traditional petrochemicals, but the investment and production costs in the process of syngas preparation account for about 50% or even more of the natural gas conversion and the entire utilization process, so the research and development of natural gas to syngas The new process of synthetic ...

AI Technical Summary

Problems solved by technology

However, in practical applications, nickel-based catalysts are easily oxidized to nickel oxide and deactivated. At the same time, sintering and carbon deposition are still the main problems restricting the practical application of nickel catalysts.

[0007] Based on the analysis of the above process and related catalysts, it can be seen that although the Pt and Rh components in noble metal catalysts have high activity and slight deactivation, these two metals are very expensive and have limited resources.

Although the initial activity of the Ni component in the non-noble metal catalyst is good, the catalyst deactivates quickly

Therefore guiding idea of ​​the present invention is based on following three points: (1) select Ru component in noble metal, so far the research that this metal component is applied to this target reaction is very little, and its price is then obviously lower than Pt, Rh, but In terms of chemical nature, it has the characteristics similar to Pt and Rh metals, with less carbon deposition and slow deactivation; (2) Ni components are selected from non-noble metals, which have high initial activity but are easy to deactivate, so they are combined with Ru components are combined to form a bimetallic catalyst, which is expected to have high activity and good anti-deactivation ability, especially to improve anti-coking and anti-sintering ability; (3) methane oxygen reforming or methane partial Oxidation is a high-temperature reaction, and the reaction temperature is usually 600-800 ° C. Metal particles, especially nano-sized metal particles, are very easy to aggregate and grow (sintering of metal active components), which significantly reduces the catalyst activity.

Images