Significance and influence of various promoters on Cu‐based catalyst for synthesizing methanol from syngas: a critical review

Abstract

Methanol synthesis from syngas is an effective method for producing fuel additives, oxygenated fuels, and other chemicals. Several promoted catalytic systems have been tested for the synthesis of methanol. Catalysts based on noble metals are extremely active in generating methanol from syngas. However, sintering, poisoning, and related expenses accounted for the switch to Cu-based catalysts. The promotion of Cu-based catalysts, even with small doses of an effective promoter, resulted in a considerable change in product selectivity. A suitable promoter is required for Cu-based catalysts used in the synthesis of methanol because it significantly impacts the electronic, geometric, or acid/base surface properties, which in turn affect the catalyst's activity and selectivity. It also significantly impacts the interactions between the catalyst's active ingredients. However, the interactions between the active component and the promoter can be adjusted or influenced by appropriate support. The present paper primarily focuses on several promoters in the copper-based catalyst for synthesizing methanol from syngas. We briefly deliberated on the need for copper-based catalysts for methanol synthesis, their reaction and mechanism, the reasons for promoter addition concerning their role and influence, the importance of CO 2 addition in feed synthesis gas and their impact on the catalyst. This paper mainly highlights the selectivity and activity of various promoted Cu-based catalysts, although different reaction parameters are the cause of promotion and inhibition in the catalyst. The effects of reaction conditions, including pressure, temperature, gas hourly space velocity (GHSV), and syngas composition, are briefly reported. This paper also comprehensively compares the effects of adding various promoters in small amounts to copper-based catalysts. This review intends to be illustrative rather than exhaustive.

Theoretical Study on the Structures and Stabilities of CunZn3O3 (n = 1–4) Clusters: Sequential Doping of Zn3O3 Cluster with Cu Atoms

“…Cu-based catalysts have played important roles in industry, such as in electrocatalytic reduction of CO 2 , methanol steam reforming and water gas shift reaction [1][2][3][4]. But at the same time, Cu-based catalysts have suffered some restrictions, such as thermal instabilities and low selectivity [1,2].…”

“…Cu/ZnO catalysts are among the commonly used Cu-based catalysts, in which Cu usually acts as the main active component and ZnO plays the dual role of promoter and support [6]. Specifically, Cu 2+ ions would be reduced to the active Cu 0 /Cu + species, and the addition of ZnO would increase copper dispersion and reducibility, which are related to enhanced catalytic activity [3,7]. Despite great progress, the interaction of the active copper component with other additives, as well as the reaction mechanisms on Cu-based catalysts, are still controversial due to the complexity of the surface [5].…”