Study On Co-based Catalysts For Hydrogen Production Via Auto-thermal Reforming Of Acetic Acid

Hydrogen is a clean energy carrier that can be obtained from fossil fuel?nature gas and coal?reforming ractions,which will result in additional emissions of greenhouse gases.As a carbon-netural energy source,biomass is a renewable energy carrier,which has attracted extensive attention,and can be decomposed via fast-pyrolysis to produce bio-oil.Acetic acid?HAc?is one of the major components in bio-oil,and has often been tested as a model compoud for hydrogen production via fixed-bed reactors,fluidised bed reactors and spouted bed rectors.In this article,HAc was selected as a model component of bio-oil and tested in auto-thermal reforming?ATR?of HAc.CoZnAl catalysts with layered double hydroxide precursor stucture?CoZnAl-LDHs?and mesoporous Co/ZrO₂ catalyst were prepared to solve issues of oxidation,sintering,and carbon deposits in the ATR process.The effects of ZnO and preparation methods on the structure and properties of the catalyst were inverstigated via a series of characterizations.The CoZnAl-LDHs catalysts and ZC0A catalyst were prepared by co-precipition and impregnation methods,respectively.The activity test results showed that ZC1A,ZC6A and ZC0A catalysts were obviously deactivated,while ZC4A catalyst presented higher activity and stability:the HAc converstion was about 100%and the hydrogen yield remained stable near 3.01 mol-H₂/mol-HAc.The characterization results indicated that the catalyst prcuresor of LDHs structure was obtained via co-precipition method;the increase of Zn content was helpful to improve specific surface area(S_BET)and reduction of cobalt species,which may explain improvement in catalytic activity,stability,anti-sintering and anti-coking.The 10Co-Al-S and 10Co-Zr-S catalysts were prepared by the evaporation-induced self-assembly method,while the 10Co-Zr-C and 10Co/Zr-I catalysts were prepared via impregnation and coprecipitation methods,respectively.The 10-h ATR test showed that the 10Co-Zr-S catalyst produced a high catalytic performace:the HAc converstion was about 100%and the hydrogen yield remained stable near 2.95mol-H₂/mol-HAc.The characterization results indicated that evaporation-induced self-assembly method was beneficial to the formation of higher S_BET,ordered crystal and morphology;the stability of Co nanoparticle can be attributed the"confinement effect"by mesoporous framework;higher dispersity and thermal stability.