Study On Ca-promoted Ni-based Catalysts For Hydrogen Production Via Auto-thermal Reforming Of Acetic Acid

As a clean energy,hydrogen can be regarded as an alternative energy of fossil energy,and can be obtained from alcohols,biomass and cellulose.Bio-oil is a raw carbon-neutral material for hydrogen production,and can be produced from fast pyrolysis of biomass.In this article,the typical component of bio-oil,acetic acid,was chosen as the feed for hydrogen production.To address the endothermicity of reforming process,auto-thermal reforming?ATR?of acetic acid?AC?was adopted with oxygen in feed and tested for hydrogen production.Catalysts of La_2-xCa_xNiO₄±? perovskite and Ca_xNi_yAl_zO_? layered double hydroxides?LDHs?were prepared to address issues of oxidation,sintering and carbon deposition during ATR process.Ca-doped La_2-xCa_xNiO_4±? catalysts were prepared via sol-gel method.The activity test results showed that La₂NiO_4±? and Ca₂NiO_3±? catalysts were obviously deactivated;The LaCaNiO_4±? catalyst presented a stable activity: the AC conversion was about 100 % and the hydrogen yield remained stable near 2.80 mol-H₂/mol-AC.The characterization results indicated that the LaCaNiO_4±? catalyst withperovskite structurewas obtained;Partial substitution of La by Ca was proved helpful for the stability of Ni particles and resistance to carbon deposition.Ca_xNi_yAl_zO_?-LDHs catalyst was prepared by co-precipitation method,and compared with Ni_xAl_yO_? and Ni_x/Ca_yAl_zO_? catalysts.The characterization results indicated that Ca_2.45Ni_0.55AlO_4.5-LDHs catalyst was prepared via co-precipitation method;Alkaline support of CaO was benificial to constrain carbon deposition and Ca₁₂Al₁₄O₃₃ carrier increased the stability of Ni particles.During ATR process,the Ca_2.45Ni_0.55AlO_4.5 catalyst showed stability with high resistance to oxidation,and carbon deposition,and produced a better catalytic performance: the AC conversion was about 100 % and the hydrogen yield remained stable near 2.75 mol-H₂/mol-AC.