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Photocatalytic hydrogen production is a promising route to the provision of sustainable and green energy. However, the excess addition of traditional electron donors as the sacrificial agents to consume photogenerated holes greatly reduces the feasibility of this approach for commercialization. Herein, considering the abundant hydroxyl groups in cellulose, the major component of biomass, we adopted glucose (a component unit of cellulose), cellobiose (a structure unit of cellulose) and dissolving pulp (a pretreated cellulose) as electron donors for photocatalytic hydrogen production over a TiO2-Au-CdS material. The well-designed ternary TiO2-Au-CdS possesses a hierarchical three-dimensional ordered macroporous (3DOM) structure, which not only benefits light harvesting but can also facilitate mass diffusion to boost the reaction kinetics. As expected, the fabricated photocatalyst exhibits considerable hydrogen production from glucose (645.1 μmol·h−1·g−1), while the hydrogen production rates gradually decrease with the increased complexity in structure from cellobiose (273.9 μmol·h−1·g−1) to dissolving pulp (79.7 μmol·h−1·g−1). Other gaseous components such as CO and CH4 are also produced, indicating the partial conversion of biomass during the photoreforming process. This work demonstrates the feasibility of sustainable hydrogen production from biomass by photoreforming with a rational photocatalyst design. [ABSTRACT FROM AUTHOR]

Photocatalytic water splitting for hydrogen production has been widely recognized as a promising strategy for relieving the pressure from energy crisis and environmental pollution. However, current efficiency for photocatalytic hydrogen generation has been limited due to a low separation of photogenerated electrons and holes. p-n heterojunction with a built-in electric field emerges as an efficient strategy for photocatalyst design to boost hydrogen evolution activities due to a spontaneous charge separation. In this work, we investigated the effect of different preparation methods on photocatalytic hydrogen production over NiO-TiO2 composites. The results demonstrated that a uniform distribution of NiO on a surface of TiO2 with an intimate interfacial interaction was formed by a sol-gel method, while direct calcination tended to form aggregation of NiO, thus leading to an uneven p-n heterojunction structure within a photocatalyst. NiO-TiO2 composites fabricated by different methods showed enhanced hydrogen production (23.5 ± 1.2, 20.4 ± 1.0 and 8.8 ± 0.7 mmolh−1g−1 for S1-20%, S2-20% and S3-10%, respectively) as compared with pristine TiO2 (6.6 ± 0.7 mmolh−1g−1) and NiO (2.1 ± 0.2 mmolh−1g−1). The current work demonstrates a good example to improve photocatalytic hydrogen production by finely designing p-n heterojunction photocatalysts. [ABSTRACT FROM AUTHOR]