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Hydrogen generation from biomass materials: challenges and opportunities

In this review, various processes for conversion of ligno(hemi)cellulosic biomass into hydrogen gas are comprehensively reviewed in terms of two main groups, namely (1) thermochemical processes [pyrolysis, catalytic pyrolysis, different gasification, co‐gasification, supercritical water gasification (SCWG)] and (2) biochemical‐cum‐biological conversions, along with electrolytic and photolytic processes. This review depicts much about the thermochemical processes for hydrogen production and its utilization via pyrolysis of biomass, gasification, gasification combined with pyrolysis, supercritical water (fluid‐gas) extraction, steam reforming (SR), auto thermal reforming (ATR), dry reforming (DR), liquid phase reforming (LPR), aqueous‐phase reforming (APR), and partial oxidation (POX) of renewable carboxylates such as bioethanol, acetic acid, phenol, glycerol, carbohydrates, different water‐soluble sugars, and bio‐oil, which are some of the areas to be explored for widespread awareness of hydrogen usage. Biomass‐based hydrogen production systems are emphasized and discussed in terms of their energetic and exergetic aspects with the help of reaction mechanisms. Different oxygenate compounds as derived from biomass with their potential catalyst tested by several literature studies and potential methods are then summarized. WIREs Energy Environ 2015, 4:139–155. doi: 10.1002/wene.111