On the solution combustion synthesis of copper based nanocatalysts for steam methanol reforming: Effect of precursor, ultrasound irradiation and urea/nitrate ratio

• Successfully synthesis of CuO/ZnO/Al2O3 by the solution combustion method.
• Effect of aluminium precursor between two alternatives: boehmite and aluminium nitrate.
• Enhancement of catalytic properties by ultrasonic mixing of primary gel.
• Reaching higher methanol conversion by utilizing ultrasound irradiation.
• Reaching higher hydrogen selectivity by utilizing urea/nitrate ratio = 1.

Steam reforming of methanol over CuO/ZnO/Al2O3 nanocatalysts synthesized by ultrasound assisted urea-nitrates combustion method was investigated. Four kinds of nanocatalysts were fabricated and their characteristic properties were studied by XRD, FESEM, PSD, BET, EDX and FTIR analyses. Their physicochemical properties proved that using boehmite instead of aluminium nitrate as the aluminium precursor leads to smaller crystallites and particles, better dispersion and more surface area and subsequently higher activity in the steam methanol reforming process. Furthermore, application of sonication for mixing of the primary gel of combustion method resulted in better dispersion of active phases, smaller and more homogeneous particles, higher methanol conversion and hydrogen production. Although enhancement of fuel/nitrates ratio increased dramatically the surface area of synthesized nanocatalysts but it had no significant effect for improving methanol conversion or hydrogen production. In a word, CZA-A-CU-UN1 had better physicochemical properties and catalytic performance for the steam methanol reforming process.

CuO/ZnO/Al2O3 nanocatalysts were synthesized by urea-nitrate combustion method. The nanocatalysts were characterized by XRD, FESEM, BET, EDX and FTIR analyses. Also their catalytic properties were studied by their utilization in steam methanol reforming process. Results show that boehmite as the aluminium precursor leads to smaller particles with higher specific surface area. Furthermore, application of ultrasound irradiation instead of conventional mixing for the preparation of primary gel in the combustion method increase the surface area and dispersion of active sites and decrease the particle size which result better catalytic performance. Finally, it was studied that lower urea/nitrates ratio leads to lower CO production as the undesired product.Figure optionsDownload high-quality image (198 K)Download as PowerPoint slide