水热条件下催化还原CO2生成甲酸的优化研究

摘要

Catalytic reduction of CO2 into formic acid was investigated through hydrothermal reactions with Al as reducer and Ni/Cu as catalysts.A thermodynamic analysis was carried out to evaluate four potential reaction path-ways of CO2 hydrothermal reduction.It was found that the most feasible pathway was as follows:HCO3-+2,H≒HCOO-+H2O,and active H atom was the best existence state of reduced hydrogen.The influences on formic acid product and carbon conversion efficiency of molar ratios of Ni/Al,Cu/Al and Al/C,reaction time and temperature were investigated in Al-Ni and Al-Cu reaction systems.It was proved experimentally that the carbon conversion efficiency during CO2reduction into formic acid with Cu catalyst was higher than that with Ni cata-lyst.The carbon conversion efficiency was 29.1%, during CO2reduction into formic acid at 300,℃ for 120 min when the molar ratio of Al/Cu/NaHCO3was 8:8:1.%采用金属Al为还原剂,金属Ni和Cu为催化剂,研究了水热条件下CO2催化转化生成甲酸的特性.针对水热还原CO2可能存在的4个反应途径进行热力学分析,计算表明,水热条件下反应途径HCO3-+2H≒HCOO-+H2O在热力学上最易进行,还原氢的最佳存在形态为活性H原子.考察了铝镍和铝铜水热反应体系中Ni/Al摩尔比、Cu/Al摩尔比、Al/C摩尔比、反应时间和温度等对产物甲酸浓度和碳转化率的影响,实验表明,Cu催化剂水热转化CO2生成甲酸的碳转化率优于Ni催化剂,当Al/Cu/NaHCO3的3组分摩尔比为8:8:1、温度300,℃、反应120,min时,水热还原CO2生成甲酸的碳转化率为29.1%,.