Catalytic Conversion of CO₂ to Value‐Added Products under Mild Conditions

Abstract

The catalytic synthesis of multi-carbon alcohols (MCA, C n H 2n + 1 OH, n ! 3) and higher hydrocarbons from CO 2 and H 2 under low or even ambient temperature are realized for the first time over a prepared bimetallic catalyst composed of nanoparticles of Pt and Ru supported on Fe 3 O 4 (RuÀPt/Fe 3 O 4 ). At 40 8C, the selectivity for alcohols, MCA, and higher hydrocarbons reached 77.1 %, 4.5 %, and 19.5 %, respectively, while that for methane was only 3.4 % (carbon based). As revealed by isotope tracer experiments using O 18 labeled water, in the hydrogenation of CO 2 over RuÀPt/Fe 3 O 4 , MCA could form by catalytic hydrolysis of alkyl, a novel reaction pathway enabling the formation of MCA at low temperature, which is different from the previously reported one based on CO insertion at high temperature. It was discovered that in RuÀPt/Fe 3 O 4 , both Ru and Pt nanoparticles played catalytic roles in the reduction of CO 2 to CH x species and the carbon-carbon coupling reaction to form alkyl, while the catalytic hydrolysis of formed long-chain alkyl occurred on Pt nanoparticles. CO 2 is a cheap, nontoxic, and abundant carbon source. The rising concentration of CO 2 in the atmosphere has been causing serious problems such as the greenhouse effect and ocean acidification. Therefore, the conversion of surplus CO 2 to hydrocarbon or oxygenated hydrocarbon is a significant subject. [1][2][3][4][5][6][7][8][9][10][11][12][13] The development of new catalytic systems capable of realizing the conversion of CO 2 to multi-carbon products (hydrocarbons or alcohols) at low or even ambient temperature is an attractive subject because such systems will not only provide high value products by consuming CO 2 , but also avoid over-emission of CO 2 in the conversion process. MCA with 3-8 carbon atoms are not only liquid fuels but also widely used as fine chemicals or solvents in producing pharmaceuticals, polymers, surfactants, detergents, paints, and printing inks. [14][15][16] The conversion of CO 2 and H 2 to multi-carbon compounds (CCMC) should be an ideal CO 2 conversion route, and H 2 can be manufactured in a large scale from renewable energy sources, including solar energy, hydropower and biomass.Pioneering efforts have been made to create catalytic systems for the conversion of CO 2 to multi-carbon compounds. It was reported that higher hydrocarbons could be synthesized from CO 2 and H 2 at high temperature over some heterogeneous catalysts. Song reported a FeÀCo bimetallic catalyst which could catalyze the reaction of CO 2 with H 2 to produce higher hydrocarbons with a selectivity of 69 % and a small amount of MCA at 300 8C. [17] Recently, Ge and Sun prepared an efficient catalyst Na-Fe 3 O 4 /HZSM-5 which can catalyze hydrogenation of CO 2 to produce hydrocarbons containing 78 % of gasoline-range (C 5 -C 11 ) ones at a CO 2 conversion of 22 % at 320 8C. [18] Sun et al. reported that a bifunctional catalyst composed of indium oxide (In 2 O 3 ) and zeolites could catalyze the reaction of CO 2 with H 2 to produce gasoline-r...

Metal Nanoclusters Synthesized in Alkaline Ethylene Glycol: Mechanism and Application

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“…In the past two decades, this strategy has been widely applied and developed, and important achievements have been made in the preparation of structurally controllable catalysts and the exploration of the relationship between structure and catalytic performance [ 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 ]. Based on the unprotected metal and alloy nanoclusters, catalysts with a high activity level, high selectivity and excellent stability for a variety of important chemical reactions have been developed [ 14 , 16 , 22 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 ].…”

Highly selective synthesis of multicarbon compounds by carbon dioxide hydrogenation over Pt nanocrystals anchoring Ru clusters

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Ultra-low temperature carbon (di)oxide hydrogenation catalyzed by hybrid ruthenium–nickel nanocatalysts: towards sustainable methane production

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