Orientation controlled photogenerated carriers on self-supporting CdS/Ni₃S₂ paper toward photocatalytic hydrogen evolution and biomass upgrading

The appropriate regulation of band structure is an effective strategy in constructing efficient photocatalytic systems. Present photocatalytic system mainly employs powder photocatalysts, which makes their recovery reliant on expensive separation processes and severely limits their industrial application. Herein, we constructed a novel CdS/Ni₃S₂ heterostructure using free-standing and flexible nickel fiber paper as the matrix. The regulated energy band structure achieves effective electron–hole separation. The as-synthesized flexible photocatalyst exhibits considerable photocatalytic activity toward the H₂ evolution reaction under visible-light irradiation, with an H₂ production rate of 5.63 μmol·cm⁻² ·h⁻¹ (14.1 mmol·g⁻¹_cat· h⁻¹ according to the catalyst loading content). Additionally, the otherwise-wasted excited holes simultaneously drive organic transformations to yield value-added organic products, thus markedly improving the photocatalytic H₂ evolution rate. Such a photocatalytic system is scaled up further, where a self-supported 20 cm × 25 cm sample achieves a champion H₂ production rate of 60–80 μmol·h⁻¹ under practical sun irradiation. This newly developed self-supported photocatalyst produces opportunities for practical solar H₂ production with biomass upgrading.