Controlling oxygen in biomass-to-energy chemistry: catalytic pathways from lignocellulosic oxygenates to renewable fuels and energy carriers

Lignocellulosic biomass is a renewable but oxygen-rich feedstock, whereas high-density fuels demand molecules of lower oxygen content, greater stability, and infrastructure compatibility; the central problem is therefore the catalytic control of oxygen chemistry. This review reorganizes biomass-to-energy catalysis around four molecular operations—oxygen removal, redistribution, retention, and functional upgrading—integrating experimental, computational, and reactor-scale evidence. Selective C–O and C–C scission through photocatalysis, hydrodeoxygenation, and tandem catalysis, enabled by multifunctional, bifunctional, and defect-engineered catalysts, converts platform oxygenates into fuel-range hydrocarbons and energy carriers; solvent environment, acid–base balance, and site proximity govern selectivity, while coking and transport limitations constrain stability. The competitiveness of biomass energy depends on molecularly selective control of oxygen, achieved through rational catalyst design, mitigation of deactivation, and integration of pretreatment, conversion, upgrading, and reactor engineering.