English

Ga-doped Cu/γ-Al₂O₃ bifunctional interface sites promote the direct hydrogenation of CO₂ to DME

• Xiaorui Chen ^1, ,
• Xuan Luo ^1, ,
• Tongming Su ^1, ,
• Xinling Xie ^1, ,
• Liuyun Chen ^1, ,
• Yuejing Bin ^2, ,
• Zuzeng Qin ^{1, ,} ,
• Hongbing Ji ^{1, 3,}

• 1.

  School of Chemistry and Chemical Engineering, Guangxi University, Nanning 530004, Guangxi Zhuang Autonomous Region, China

• 2.

  College of Biological and Chemical Engineering, Guangxi University of Science and Technology, Liuzhou 545005, Guangxi Zhuang Autonomous Region, China

• 3.

  Zhejiang Green Petrochemical and Light Hydrocarbon Transformation Research Institute, Zhejiang University of Technology, Hangzhou 310014, Zhejiang Province, China

Corresponding author: Zuzeng Qin, Email: qinzuzeng@gxu.edu.cn

• Received Date: 05 May 2025
  Accepted Date: 24 June 2025
  Revised Date: 21 June 2025
  Available Online: 15 October 2025
• Fund Project:

  the National Natural Science Foundation of China 

  the Guangxi Key Research and Development Program 

Abstract: The reaction of CO₂ catalytic hydrogenation to dimethyl ether (DME) usually relies on a Cu-containing metal oxide/molecular sieve system; however, the migration of copper species to molecular sieves is unavoidable during the reaction, leading to the loss of Cu⁰ sites and acidic sites. In this work, a Cu/x%Ga-γ-Al₂O₃ bifunctional catalyst was synthesized via the coprecipitation method. Ga was doped into the γ-Al₂O₃ lattice at a low concentration, forming interfacial active sites with surface Cu⁰ species to achieve the hydrogenation of CO₂ to DME. Experimental studies combined with Density functional theory (DFT) calculations demonstrate that the catalyst remains stable for 180 h and that the Ga-doped Cu/γ-Al₂O₃ interface sites exhibit catalytic effects on CO₂ hydrogenation to CH₃OH and CH₃OH dehydration to produce DME. The doping of Ga increases the specific surface area of the catalyst, reduces the particle size of Cu⁰, enhances the number of acidic and basic sites on the catalyst, and promotes the adsorption of H₂ and CO₂. In addition, a new reaction pathway for DME synthesis was proposed. This work removes the dehydrated component of a traditional Cu-based bifunctional catalyst, enabling two reactions to occur at the same active sites, thus providing a new strategy for the design of novel dimethyl ether synthesis bifunctional catalysts.

Key words:
• Bifunctional catalyst
•  /  CO₂ hydrogenation
•  /  DME synthesis
•  /  Interface
•  /  Ga-doped
•  /  DFT calculation

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