固体氧化物电解池（solidoxideelectrolysiscells，SOEC、共电解H2O-C02是减少C02排放和进行可再生能源转化储存的潜在有效途径之一。该文开展了SOEC共电解H2O-CO2实验研究，在产物中发现甲烷气体生成。不同原料气配比条件下的共电解实验结果表明，SOEC共电解H2O-CO2电化学性能介于电解水蒸气和电解C02之间。增加工作电压和反应气体中C02的分压有利于提高产物中CH4的浓度，逆向水气变换反应是CO生成的主要途径。与H2-CO在SOEC阴极的反应产物组成相比，H2O-C02共电解产物中H2浓度非常低，据此推测产物CH4主要由H20和C02在Ni催化剂表面原位电化学转化生成。“,”Co-electrolysis of H20-CO2 in solid oxide electrolysis cells is one of the efficient ways to reduce CO2 emission and to store renewable power. H20-CO2 co-electrolysis performance in a solid oxide electrolysis button cell was tested. Methane composition was discovered in the reduction product gas. The results indicate that the electrochemical performance of H20-CO2 coelectrolysis reaction is between those of steam electrolysis and CO2 electrolysis, and CO is primarily produced via reverse water gas shift reaction. The concentration of methane in reduction product can be raised by increasing operating voltage or increasing CO2 concentration in inlet gas. Different with direct H2-CO methanation, little H2 can be found in H20-CO2 coelectrolysis product. A reaction pathway of CH4 production via in-situ H20-CO2 electrochemical conversion on the Ni catalyst surface is proposed.