The development and characterization of Ni-Cu/Al₂O₃ catalyst for hydrogen production via multi-fuel reforming

• Main Author: Khzouz, Marcin
• Published: University of Birmingham 2014
• Subjects: 660; TP Chemical technology
• Online Access: https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.633325

Developing a catalyst that accepts a wide range of fuels for hydrogen production is an important design aspect for the successful multi-fuel reformer. This thesis aims to synthesize and evaluate Ni-Cu/Al\(_2\)O\(_3\) catalysts for methanol and methane steam reforming. Detailed characterizations of catalysts, as well as the role of the bimetallic nature of Ni-Cu metals on the catalytic reaction are presented and discussed. A series of Ni\(_x\)-Cu\(_y\)/Al\(_2\)O\(_3\) catalysts with various metals loadings (x= 10, 7, 5, 3 and 0% weight and y= 0, 3, 5, 7 and 10%, respectively) were prepared. The temperature programed reduction revealed that bimetallic catalysts displayed a new hydrogen uptake peak compared with monometallic metal catalyst and this was attributed to NiCuO reduction. The X-ray diffraction patterns indicated Ni\(_x\)Cu\(_1\)\(_-\)\(_x\)O phase formation. The methanol steam reforming was evaluated over the prepared catalysts over the range of temperatures 225-325°C in a fixed bed reactor. It was found that bimetallic Ni-Cu had a strong influence on the amount of CO\(_2\) and CO by controlling the water gas shift reaction and decomposition reaction. The highest amount of hydrogen produced among the other prepared catalysts was 2.2 mol/mol-CH3OH for 5%Cu-5%Ni at 325°C. Low temperature methane steam reforming at 500-700°C was investigated. The synergetic effect between Cu and Ni metals was also investigated, showing that Cu provides a stabilizing effect by forming Ni-Cu alloy and controlling the catalyst structure. The 7%Ni-3%Cu revealed the highest conversion of 71.1% methane and produced the maximum amount of hydrogen at 2.4 mol/mol-CH4 among the other prepared catalysts at 600°C and S/C of 3. The bimetallic reacted Ni-Cu catalysts revealed less carbon selectivity (0.9% for 5%Ni-5%Cu) compared to 10%Ni (4.6%) catalyst at 600°C.