Effect of Preparation Method on the Performance of Cu−Mn−(La)−Zr Catalysts for CO₂ Hydrogenation to Methanol

Abstract

A series of CuÀ MnÀ (La)À Zr catalysts with molecular ratios of 6 : 3 : (0.35) : 1 was synthesized by sol-gel (CMLZÀ S), co-precipitation (CMLÀ CP, CMLZÀ CP) and hydrothermal (CMLZÀ H) methods, respectively. The effects of the Mn and La on the activity of catalysts were investigated. It was found that the addition of La promoted the formation of the medium basic sites. Mn acted as an electronic promotor that transfer electrons through redox reactions, causing other metals to exhibit different valence states, thus promoting the adsorption and activation of H 2 and CO 2 . At a certain temperature, methanol selectivity decreased in the order of CMLZÀ H > CMLZÀ S > CMLZÀ CP > CMZÀ CP. The selectivity of methanol is correlated with the distribution of basic sites. For the CMLZÀ H catalyst, the highest percentage of moderate basic sites facilitated the activation of CO 2 , resulting in the highest selectivity of methanol. The CO 2 conversion was correlated with the Cu specific surface area.

Effect of Ni content on Cu–Mn/ZrO2 catalysts for methanol synthesis from CO2 hydrogenation

“…25 In addition to Mn 2 O 3 , another minor peak might be assigned to the diffraction of a coppermanganese composite oxide. 26 For reduced catalysts (Fig. 2b), diffraction peaks corresponding to Cu 2 O (PDF#65-3288) at 2θ = 36.5°, 42.5°a nd 61.5°, as well as Cu (PDF#04-0836) at 2θ = 43.3°, 50.5°a nd 74.1°, were observed.…”

“…The α peak at around 200 °C indicated the desorption of atomic hydrogen on the surface of the Cu metal, while the β peak at about 300 °C might derive from the bulk-phase Cu species with strong H 2 adsorption. 26,40 Additionally, CMNZ-0.01 exhibited the lowest desorption temperature among the catalysts, suggesting the easy desorption of adsorbed H 2 . The total H 2 desorption was found to be higher for all Ni-containing catalysts compared to the CMZ catalyst due to the improved hydrogenation activation capability from surface copper and nickel.…”

“…25 In addition to Mn 2 O 3 , another minor peak might be assigned to the diffraction of a copper–manganese composite oxide. 26…”

CO2heterogeneous hydrogenation to carbon-based fuels: recent key developments and perspectives

“…266 Wang et al also investigated the effect of the preparation method on the performance of Cu–Mn–(La)–Zr catalysts for CO 2 hydrogenation to methanol. 267 The catalysts prepared via the sol–gel and co-precipitation methods had a larger Cu specific surface area, thus exhibiting higher CO 2 conversion. In contrast, the catalysts prepared via the hydrothermal method had more oxygen vacancies, exhibiting higher CH 3 OH conversion.…”

Electrocatalytic and Photocatalytic CO2 Methanation: From Reaction Fundamentals to Catalyst Developments

“…[3] To address the challenge, carbon capture and utilization (CCU) technology, which aims to capture and convert CO 2 into valuable products, has been considered a viable strategy to reduce CO 2 emissions and provide new economic opportunities. [4] Among the fuel products (such as CO, [5] CH 4 , [6] CH 3 OH, [7] HCOOH, [8] and low-carbon olefins [9] ) related to CO 2 conversion, methane (CH 4 ) is an ideal choice due to its high energy density, easy compressibility and storage, and potential application as a substitute for non-renewable natural gas. [10] Compared to non-renewable energy sources such as fossil fuels, electricity can be produced via renewable energies such as wind, solar, and hydropower.…”