Photocatalytic reforming of pinewood (Pinus ponderosa) acid hydrolysate for hydrogen generation

Dilute acid hydrolysis of milled Pinus ponderosa (pinewood) was performed in a high-temperature high-pressure 300 ml SS316 Parr reactor to produce sacrificial electron donors for downstream photocatalytic H2 generation. Samples of the hydrolysate withdrawn at regular time intervals were analysed for total organic carbon (TOC), sugars and organic compounds. The influence of acid type (HCl, H2SO4, and HNO3) and its concentration, temperature, residence time and biomass loading on pinewood hydrolysis and release of the glucose and xylose sugars (GX) was investigated. Maximum GX sugar yield was obtained with 1 v/v% HCl hydrolysis of 6.66 wt% pinewood slurry at 180 °C for 120 min. The hydrolysate was treated with activated charcoal (AC) and photoreformed for H2 generation using 1% Pt/TiO2 catalyst. Under optimized reaction conditions, 8 consecutive photocatalytic cycles of the hydrolysate produced cumulative yield of 19.9 ml H2/g pinewood, which is 26 mol% of GX observed in the hydrolysate.