Co在超细Mo-Co-K催化剂合成低碳醇中的作用

采用BET、XPS和TPD表征手段对超细Mo-Co-K催化剂的织构、表面结构和吸附行为进行了研究，结合催化剂的合成低碳醇性能，论证了Co在超细Mo-Co-K催化剂合成低碳醇中的作用。Co的加入提高了催化剂合成低碳醇的活性和选择性，同时也提高了催化剂的比表面并促进了微孔的形成，催化剂的催化性能与其织构之间呈现出很好的顺变关系。Co对催化剂中可能作为合成低碳醇活性中心的低价Mo物种的电子结合能值影响较小。Co的加入降低了H2和CO在催化剂表面的强吸附中心的吸附强度，从而有利于合成低碳醇反应的发生。研究结果表明，Co仅仅是作为结构助剂，通过调变催化剂的织构和催化剂表面的H2及CO的强吸附中心而影响其合成低碳醇性能的。

STUDY ON THE ROLE OF Co IN ULTRAFINE Mo-Co-K CATALYSTS FOR THE SYNTHESIS OF HIGHER ALCOHOLS

Ultrafine Mo-Co-K catalysts were characterized by BET,XPS and TPD techniques in this paper. By comparing the characterization results with the catalytic performance for higher alcohol synthesis of the catalysts,the role of Co in ultrafine Mo-Co-K catalysts for the synthesis of higher alcohols was studied. The addition of Co into ultrafine Mo-K catalyst enhanced the activity and selectivity to higher alcohols of the catalyst, on the other hand,the addition of Co enhanced the specific surface area of the catalyst and promoted the formation of smaller pores. The catalytic performance of the catalysts correlated with their texture very well, and the above two tendency showed an excellent corresponding relationship. The electron binding energy of lower valence Mo species which might act as the active sites of higher alcohol synthesis was affected by Co less obviously. The addition of Co into ultrafine Mo-K catalyst diminished the adsorption strength of H_2 and CO on the strong adsorption sites of the catalyst,which might improve the reaction of higher alcohol synthesis. The results showed that Co acted only as a structure promoter in the catalysts and affected the catalytic performance by changing the texture and strong adsorption centers for H_2 and CO of the catalysts.