Low-Temperature Direct Catalytic Hydrothermal Conversion of Biomass Cellulose to Light Hydrocarbons over Pt/Zeolite Catalysts

Direct catalytic hydrothermal conversion of cellulose to C₃+C₄ hydrocarbons at a low temperature (443 K) over a Pt/zeolite catalyst without hydrogen or other expensive reagents was investigated. Pt supported on NH₄ ⁺-form ultra-stable Y-type (NH₄-USY) zeolite catalyst, which showed the highest activity among the tested Pt/zeolite catalysts, has appropriate acidity and a suitable active Pt site. The C₃+C₄ hydrocarbon yield reached 14.5 C-% during the reaction over the Pt/NH₄-USY catalyst at 443 K after 72 h of the reaction. Results showed that the acid strength of the zeolite support was an important factor affecting the cellulose decomposition activity. Because of their structural sensitivity, Pt/zeolite catalysts with Pt particles larger than 5 nm, including Pt/NH₄-USY catalyst, showed higher TOF values than catalysts with Pt particles smaller than 5 nm.