Coordination unsaturated structure of titanium sulfate promoting the carbon chain growth for dimethyl ether oxidation
Xiujuan Gao,
Faen Song,
Xiaoxing Wang,
Junfeng Zhang,
Qi Yang,
Yunxing Bai,
Qike Jiang,
Xingchen Liu,
Tao Zhang,
Yizhuo Han,
Yisheng Tan,
Qingde Zhang
Affiliations
Xiujuan Gao
State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001, China
Faen Song
State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001, China
Xiaoxing Wang
State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001, China; Corresponding authors.
Junfeng Zhang
State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001, China
Qi Yang
State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001, China; University of Chinese Academy of Sciences, Beijing 100049, China
Yunxing Bai
State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001, China; University of Chinese Academy of Sciences, Beijing 100049, China
Qike Jiang
Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China; Dalian National Laboratory for Clean Energy, CAS, Dalian 116023, China
Xingchen Liu
State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001, China
Tao Zhang
State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001, China; Corresponding authors.
Yizhuo Han
State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001, China
Yisheng Tan
State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001, China
Qingde Zhang
State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001, China; Dalian National Laboratory for Clean Energy, CAS, Dalian 116023, China; Corresponding author at: State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001, China.
Polyoxymethylene dimethyl ethers (DMMx, CH3O(CH2O)xCH3, x = 1–8) are appealing oxygenated chemicals with potential applications mainly used as sustainable fuels and solvents. The growth of longer C-O chain for direct oxidation of dimethyl ether (DME) to DMMx is especially important, but the construction of the acid sites with different strengths and matched redox sites faces great difficulties. Herein, the gradient acidity and enhanced oxidizability have been successfully created by regulating coordination structure of titanium sulfate (Ti(SO4)x). The formation of a higher proportion of weak-medium acid sites and appropriate redox sites over a Ti(SO4)x/activated carbon (AC) catalyst with nitrogen treatment significantly promotes the synthesis of larger molecules, with DMM2–3 selectivity up to 42.2%. Combined with the characterizations, designed experiments and theoretical calculations, the configurations of Ti(SO4)x and their local chemical environment are revealed. The different distortions of Ti(SO4)x structure in nitrogen atmosphere result in the various coordination unsaturated Ti atoms located at the center of polyhedral, which is the main reason for the gradient acidity distribution and enhanced oxidative property.
