Mg-containing Cu/Zn/Al industrial catalysts for methanol synthesis have been widely used in coal industry. The objective of this work is to investigate the influence of precipitation methods and Mg addition on the performance of Cu/Zn/Al/Mg methanol synthesis catalyst. A series of Cu_0.6Zn_0.3Al_0.1Mg_x catalysts (x: 0-0.04) were prepared by co-precipitation and fractional-precipitation methods, respectively. The catalyst samples were characterized with various methods including XRD, TG-MS, XPS, SEM, TEM/EDS, N₂ physisorption and N₂O chemisorption. Results show that Mg improved the BET surface area and Cu dispersion of the catalysts prepared by co-precipitation, while the corresponding catalytic activity decreased with the addition of Mg. Fractional precipitation could facilitate the Cu substitution by Zn in the subcarbonate precursor, and eliminate the negative effect caused by Mg addition. Though the formation of Mg-Al hydrotalcite was unfavorable, the catalysts obtained with fractional precipitation demonstrated better catalytic performances than those prepared by co-precipitation method. It is suggested that fractional-precipitation method is more suitable than co-precipitation for preparing the Cu/Zn/Al/Mg methanol synthesis catalyst.

用于甲醇合成的含镁Cu / Zn / Al工业催化剂已广泛用于煤炭工业。这项工作的目的是研究沉淀方法和添加Mg对Cu / Zn / Al / Mg甲醇合成催化剂性能的影响。通过共沉淀法和分步沉淀法分别制备了一系列Cu _0.6 Zn _0.3 Al _0.1 Mg _x催化剂（x：0-0.04）。用各种方法对催化剂样品进行表征，包括XRD，TG-MS，XPS，SEM，TEM / EDS，N ₂物理吸附和N ₂O化学吸附。结果表明，Mg改善了共沉淀法制备的催化剂的BET表面积和Cu分散度，而相应的催化活性随Mg的添加而降低。少量沉淀可以促进次碳酸盐前体中的Zn取代Cu，并消除因添加Mg引起的负面影响。尽管不利地形成了Mg-Al水滑石，但与共沉淀法制备的催化剂相比，分步沉淀法制得的催化剂具有更好的催化性能。有人提出，分步沉淀法比共沉淀法更适合制备Cu / Zn / Al / Mg甲醇合成催化剂。