Efficient and stable supercritical-water-synthesized Ni-based catalysts for supercritical water gasification

Abstract

Catalyst sintering problem hinders the development of effective supercritical water gasification (SCWG) at milder supercritical water (SCW) temperature for gas fuel production from wet biomass resources. Herein, we prepared a series of supported Ni catalysts by hydrothermal synthesis method particularly operated at the SCW region, and studied the activity and property stability of these newly developed catalysts for SCWG. Supporting materials studied for Ni include ZrO2, Ce-promoted ZrO2, Al2O3, Mg-promoted Al2O3, active carbon and carbon nanotube, and the supercritical water synthesis (SCWS) was conducted at 500 °C, 23 MPa in batch reactor using metallic nitrates as starting feed. SCWG results and catalyst characterization (XRD, SEM-EDS, N2 adsorption/desorption and TGA) confirmed the high activity, superiorly stable crystalline structure and pore structure, and excellent regeneration ability of the SCWS-prepared catalysts (especially Ni/MgO-Al2O3) for SCWG reactions, showing that SCWS is a promising method to develop active and stable catalyst for SCWG process.