CuZn catalysts HMF Lewis acids NMR acidic clays alditol amination aqueous phase biochar-supported metal catalysts biofuel production biofuels biomass biomass conversion biomass valorization biorefinery calcination atmosphere calcination temperature carbohydrates carbon nanotubes catalytic materials catalytic transfer hydrogenation citronellal ethylene glycol heterogeneous and homogeneous catalysts heterogeneous catalysis hybrid materials hydrogen donors hydrogenolysis hydrothermal carbonization lignin