Investigation on molybdenum carbide catalyst, its oxide precursor and its modifiers was performed using temperature programmed surface reaction (TPSR) technique, BET surface specific area and X-ray diffraction (XRD) measurement. The carbide catalyst and its modifiers were evaluated using microreactor apparatus. The evaluation result showed that the addition of nickel promoted the POM to syngas, the addition of copper exhibited weaker promotion at the initial stage, but it turned unfavorable to the POM to syngas hereafter. As for potassium doped catalyst, it was unfavorable to the POM. According to the characterizations, the effect of added metals on the carburization, especially under the condition of POM, was elucidated. (C) 2003 Elsevier B.V. All rights reserved.