Catalytic conversion of CO_2 into chemicals and fuels is an alternative to alleviate climate change and ocean acidification.The catalytic reduction of CO_2 by H_2 can lead to the formation of various products:carbon monoxide,carboxylic acids,aldehydes,alcohols and hydrocarbons.In this paper,a comprehensive thermodynamics analysis of CO_2 hydrogenation is conducted using the Gibbs free energy minimization method.The results show that CO_2 reduction to CO needs a high temperature and H_2/CO_2 ratio to achieve a high CO_2 conversion.However,synthesis of methanol from CO_2 needs a relatively high pressure and low temperature to minimize the reverse water-gas shift reaction.Direct CO_2 hydrogenation to formic acid or formaldehyde is thermodynamically limited.On the contrary,production of CH_4 from CO_2 hydrogenation is the thermodynamically easiest reaction with nearly 100%CH4 yield at moderate conditions.In addition,complex reactions with more than one product are also calculated in this work.Among the considered carboxylic acids(HCOOH,CH_3COOH and C_2H_5COOH),propionic acid dominates in the product stream(selectivity above 90%).The same trend can also be found in the hydrogenation of CO_2 to aldehydes and alcohols with the major product of propionaldehyde and butanol,respectively.In the process of CO_2 hydrogenation to alkenes,low temperature,high pressure,and high H_2 partial pressure favor the CO_2 conversion.C_4H_6 is the most thermodynamically favorable among all considered alkynes under different temperatures and pressures.The thermodynamic calculations are validated with experimental results,suggesting that the Gibbs free energy minimization method is effective for thermodynamically understanding the reaction network involved in the CO_2 hydrogenation process,which is helpful for the development of high-performance catalysts. Catalytic conversion of CO_2 into chemicals and fuels is an alternative to alleviate climate change and ocean acidification. The catalytic reduction of CO_2 by H_2 can lead to the formation of various products: carbon monoxide, carboxylic acids, aldehydes, alcohols and hydrocarbons. , a comprehensive thermodynamics analysis of CO_2 hydrogenation is conducted using the Gibbs free energy minimization method. The results show that CO_2 reduction to CO needs a high temperature and H_2 / CO_2 ratio to achieve a high CO_2 conversion. How, synthesis of methanol from CO_2 needs a relatively high pressure and low temperature to minimize the reverse water-gas shift reaction. Direct CO 2 hydrogenation to formic acid or formaldehyde is thermodynamically limited. On the contrary, production of CH_4 from CO_2 hydrogenation is the thermodynamically easiest reaction with nearly 100% CH4 yield at moderate conditions. addition, complex reactions with more than one product are also calculated in this w The same trend can also be found in the hydrogenation of CO_2 to aldehydes and alcohols with the major product of org.Among the considered carboxylic acids (HCOOH, CH_3COOH and C_2H_5COOH), propionic acid dominates in the product stream propionaldehyde and butanol, respectively.In the process of CO 2 hydrogenation to alkenes, low temperature, high pressure, and high H_2 partial pressure favor the CO_2 conversion. C_4H_6 is the most thermodynamically favorable among all alkynes under different temperatures and pressures. thermodynamic calculations are validated with experimental results, suggesting that the Gibbs free energy minimization method is effective for thermodynamically understanding the reaction network involved in the CO 2 hydrogenation process, which is helpful for the development of high-performance catalysts.