Hydrogen production through catalytic supercritical water gasification: Energy and char formation assessment

•H2 production and solid char formation through catalytic SCWG of biomass are studied.•The Gibbs minimization concept is modified to optimize catalyst impact in the process.•The basic model cannot predict the coal’s char formation at 750 °C and 24.55 MPa.•The energy consumption per hydrogen production holds a minimum value of 828.6 °C.•A higher CGE causes larger gas yields and smaller solid char content.