| The consumption of coal, oil and other fossil fuels is increasing, then fossil fuels are depleting with the development of society and economy, thus, we need to explore some new type of energy to substitute traditional fossil energy. As a clean and efficient liquid fuel, ethanol has received widespread attention. There are many methods for ethanol synthesis, one of the most potential ways is catalytic conversion from syngas which is derived from coal. It is propitious to the sustainable development of energy requirements of China. Ethanol synthesis from syngas has opened a new way in clean coal technology development. It has broad market prospects, strategic significance and far-reaching effects on improving energy security of our country. In our previous work, it has been found that Cu/Zn/Al catalyst prepared by complete liquid-phase method used for methanol synthesis has a certain capacity of ethanol synthesis. In this paper, the catalytic performance and the structure of Cu/Zn/Al catalyst modified by ethylene glycol, triethylamine and pH are investigated. The catalysts are characterized by XRD, TPR, NH3-TPD, BET and XPS. The main research conclusions are listed as follows:1. The change of ethylene glycol concentration, the addition of triethylamine and the adjusting of pH value have great influence on the catalysts performance. When the ethylene glycol concentration reaches 21%, the CO conversion reaches 34%, the ethanol selectivity reaches 10%.2. When Cu and Cu2O are highly dispersed in the catalyst, it is propitious to the ethanol synthesis. The synthesis of ethanol not only need high content of Cu+species, but also need the appropriate ratio between Cu+ and Cu0 species.3. If a high temperature reduction peak exists in the H2-TPR profile, it means Cu species has strong interaction with zinc or aluminum species. In this condition the ethanol selectivity will be higher, but when a great amount of Cu species is reduced and the high temperature reduction peak disappears, the ethanol selectivity will decrease.4. When a little amount of weak acid sites and medium strong acid sites exist in the catalyst, the activity and ethanol selectivity will increase.5. The smaller specific surface area of catalyst is not beneficial for ethanol synthesis. |
