Preparation And Catalytic Behavior Of Structured High Dispersed Cu-based Catalysts On Steam Reforming Of Dimethyl Ether

Environmental pollution and energy crisis have become global issues in the process of human development which can’t be ignored. Among the numerous coping strategies, efficient and clean hydrogen energy technology has received extensive attention from domestic and overseas researchers. Because dimethyl ether is high hydrogen content, non-toxic, easy storage and transportation, the steam reforming of dimethyl ether process (DME SR) is considered as one of the most promising technologies. Meanwhile, the porous anodic alumina (PAA) as a new integration support, with excellent heat and mass transfer abilities and plasticity, has been pursuing in catalytic field.In this study, firstly, the electrochemical method was applied to remove the barrier layer to improve its conductivity. By studying the changes of pH. systemic current and alumina content at the cathode over time, it was found that the electrochemical reaction process of eliminating PAA barrier layer had three stages. By studying the effects of KC1, NaCl, KNO3 solutions on conductivity of PAA support, it was obtained that continued dissolution of barrier layer by the enriching OH- ions at the cathode is the key to enhance PAA’s conductivitySubsequently, X-Cu/EC-γ-AI2O3/Al catalysts prepared on conductive PAA by electroplating method were studied to alleviate the sintering of Cu in DME SR. Different additives were selected to improve the stability of Cu, the result showed Ni-Cu> Ce-Cu Zr-Cu catalysts. By investigating the process conditions of electroplating for supporting Ni, it was showed Ni100-Cu (2 min, a current density of 100 A/m2) exhibited the best stability:DME conversion remained 100% and H2 yield kept above 75% within 62 h at 400℃. According to the characterizations from XRD, N2O-TPR, H2-TPR on Ni-Cu catalysts, the results showed that because of the addition of Ni, reduction temperature of CuO was reduced, dispersion and specific surface area of Cu were increased, which ultimately improved the anti-sintering capacity of Cu at high temperature in DME SR.Finally, new supporting methods for preparing high dispersed catalysts with low loading on plate-type PAA were developed, namely ultrasonic impregnation, electroless plating and electroplating methods.The effects of different process conditions on the distribution and loading of the active ingredients, and the catalytic activities of catalysts in DME SR were investigated. Ultrasonic impregnation could be used to prepared catalysts with small particles. Metal was loaded directly and effectively by electroless plating. But it was difficult to control the deposition velocity and the coating was fragile. Electroplating on conductive PAA was an easy and efficient method with promosing applications.