Research On Hydrodeoxygenation Of M-cresol Over Pt/TiO₂

Biomass energy is a plentiful,renewable and clean energy resource.The bio-oils got by fast pyrolysis of biomass has much oxygen-containing compounds such as guaiacol,syringyl,phenol,anisole and cresol,etc.Bio-oils have such high oxygen contents resulting in poor property such as corrosive,low calorific value and viscosity etc,Therefore,the oxygen removal is an essential processing goal.Hydrodeoxygena-tion activity of phenolics over noble metal catalysts is excellent.The purpose of this work is to gain insights into the reaction mechanism of hydrodeoxygenation of phe-nolics over Pt/TiO₂ catalyst.The paper also investigated the effects on catalytic activ-ity and the properties of catalysts such as reduction temperature and the addition of CeO₂.In order to get the reaction pathways of m-cresol reaction,hydrodeoxygenation of m-cresol and intermediate products?such as MCHone,MCHol,MCHane and Tol?had been investigated over Pt/TiO₂ catalyst at 250 ^oC and ambient hydrogen pressure.Hydrodeoxygenation of m-cresol have two major reaction pathways?HYD path and DDO path?and the DDO path is predominant.The effect of reduction temperature on catalytic activity,the structures and properties of Pt/TiO₂ was investigated by various techniques such as XRD,TEM,BET,XPS,CO-TPD,NH₃-TPD,H₂-TPR etc.The re-action mechanism of m-cresol direct oxygenation was also studied by activities test combined with above characterization methods.The interaction of metal-support is benefit with increasing the activity of direct deoxygenation and promote the reduction of TiO₂.Elevated reduction temperature can promote the reduction Ti⁴⁺to Ti³⁺,which migrate to the surface of Pt atoms resulting in decreasing of exposed Pt atoms.There-fore,catalytic activity decrease with the reduction temperature increasing.The direct deoxygenation of m-cresol take place in metal-support interface,the oxygen vacancies located at metal-support interface can interact with oxygen in m-cresol to active C-O bond.Activated hydrogen needed for the fracture of the C-O bond was provided by Pt located at metal-support interface.The effects of catalyst Pt/TiO₂ decorated by CeO₂ on catalytic activity and the properties was also studied.The catalysts decorated by CeO₂ have higher Pt disper-sion and better catalyst stability,but the selectivity of Tol is decreased.