Sustainable hydrogen from bio-oil - Catalytic steam reforming of acetic acid as a model oxygenate

Studies were conducted with acetic acid (HAc) as model oxygenate for the design of active and stable catalysts for steam reforming of bio-oil. Pt/ZrO₂ catalysts were prepared by wet impregnation technique. The Pt/ZrO₂ catalysts showed high activities at initial time on stream, but lost its activity for steam reforming (H₂ production) rapidly. During HAc/H₂O reaction over Pt/ZrO₂, conversion was close to 100% and constant for 3 hr, however, yields of products changed with time. In the beginning (5 min), H₂ and CO₂ were the main products, CH₄ and CO were observed in small quantities. During HAc/H₂O reaction over ZrO₂ (without Pt), HAc conversion was close to 90%. The conversion of HAc and yields of the products were constant for 3 hr. However, no steam reforming activity (H₂ and CO) was observed, and only acetone and CO₂ were observed as products. Both Pt/ZrO₂ and ZrO₂ were very active for HAc conversion. However, H₂ and CO, i.e., steam reforming products, were produced only over Pt/ZrO₂ and not over ZrO₂. ZrO₂ showed acetone yields similar to those observed over Pt/ZrO₂ after 25 min time on stream. The presence of acetone in the product mixture and formation of deposits on ZrO₂ indicated a role for acetone in catalyst deactivation.