Recent progress of metals supported catalysts for hydrodeoxygenation of biomass derived pyrolysis oil

The production of alternative fuels is more than essential to the energy and transportation sectors. Biomass based oil generation through a pyrolysis process is one of the attempts to develop a sustainable way for energy production. One of the main concerns of pyrolysis oil is the undesired properties such as high oxygen level, acidic, viscosity and low heating value. The corrosiveness of pyrolysis oil is a threat to the existing transportation infrastructure and modern engines. For the past decade, research studies have been conducted to develop catalysts that can increase the pyrolysis oil quality through hydro-deoxygenation. From monofunctional, bifunctional with noble metals and non-noble metals to bimetallic catalysts (two metals and a support), hydro-deoxygenation has rapidly evolved in term of catalysts. This review paper studied and analyzed the progress of metals supported catalysts for hydro-deoxygenation of pyrolysis oil and its model compounds. Ru, Pt and Pd supported catalysts performed best among the noble metals supported catalysts. However, noble metals supported catalysts are expensive. Non noble metal such as Ni’s performance was comparable to Pt supported catalysts. Recently developed bimetallic catalysts were aimed to improve performance of hydrodeoxygenation at low cost. Nickel and Cobalt were widely used non-noble metals for bimetallic catalysts. •The evolution of catalysts for HDO of pyrolysis oil is reported.•Mono-functional, bifunctional, bimetallic and multi-metallic catalysts are discussed.•Non-noble metals based catalysts are preferred over noble metals based catalysts.•Ni based catalysts had the highest selectivity for hydrocarbons compounds.•Bimetallic supported catalysts are developed for reducing the overall cost.