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Photoelectrochemical (PEC) nanomaterials are critical to producing clean oxygenation or value-added chemical production by utilizing sustainable solar energy, but are always limited by simultaneous integration of architectural engineering and electronic regulation in one structure. Directed by density functional theory (DFT) calculations and finite element analysis (FEA), the bio-inspired ivy-like Fe2O3 heterostructures with enriched oxygen defects on TiO2 nanofibers are designed for boosting PEC performances. Ivy-like Fe2O3 photo-sheets remarkably enhanced the light harvesting by multiple light-mater interactions. The oxygen vacancies on Fe2O3 photo-sheets could aid the photons catching and promote the reactivity at active sites. More importantly, demonstrated by a well-designed dynamic observation, the abundant tip-edges within ivy-like Fe2O3 photo-sheets enabled the surface of heterostructure with hydrophilic and aerophobic properties. The functionalized surface allowed the rapid desorption of produced bubbles and thus ensured a high density of unoccupied active sites for electrolyte accessing. Featured by these attributes, the Fe2O3@TiO2 nanofibers delivered an excellent photocurrent of 40.8 mA/mg, high donor density (1.2 × 1018 cm−3), and rapid oxygen production rate (1 mmol/(L·h)). This work demonstrates a new strategy on nano-structural design for enhancing light-harvesting and making a hydrophilic/aerophobic surface on low-dimensional oxide nanomaterial, holding great potential on designing high-performance PEC devices for producing survival source gas, carbon-neutral fuel, and valued-chemicals. [ABSTRACT FROM AUTHOR]

Structural optimization and surface engineering of photocatalysts are considered as promising approaches to improve their performances effectively. The precise control of morphology and compositions during synthesis of photocatalysts is important but yet challenging. In this work, without any aid of surfactant, urchin-like reduced graphene oxide/sodium titanate (RGO/Na2Ti3O7) microspheres were fabricated by a facile, one-pot hydrothermal reaction with good reproducibility. Both microsized and nanosized graphene oxide sheets can serve as catalysts of manipulating the growth kinetics of urchin-like Na2Ti3O7 microspheres by accelerating nucleation while inhibiting Ostwald ripening. The coupling of hierarchical Na2Ti3O7 with RGO significantly enhanced photoelectrochemical and photocatalytic performances under visible-light irradiation. The steady-state photocurrent density of RGO/Na2Ti3O7-based photoanode was 13.6 times higher than those based on pristine Na2Ti3O7, thanks to the narrowed bandgap, enhanced light harvesting, and effective electron transfer. The surfactant-free RGO/Na2Ti3O7 microspheres were further demonstrated as photocatalysts endowed with photothermal effect enhanced photocatalytic activity. Toward H2 generation by hydrolysis of ammonia borane, the maximum hydrogen production rate of RGO/Na2Ti3O7 reached 2.73 times higher than that of Na2Ti3O7, mainly due to the excellent photothermal efficiency up to 67.2% (higher than that of noble metal, e.g., Au dumbbell-like structure). It is believed that our understanding and reliable strategy could be extendable to construct new photocatalysts and systems toward effective solar energy harvesting and utilizations. [ABSTRACT FROM AUTHOR]

Photocatalyst-assisted degradation of organic pollutants, which exhibits a novel strategy for solar-energy utilization, possesses enormous potential in various applications. Extending the light-absorption range in the spectrum of sunlight and improving light-conversion efficiency are always primary issues to enhance the catalytic performance of these photocatalysts. Herein, a new structure of gold-nanorod-decorated TiO2 rambutan-like microspheres is designed, which exhibits superior photocatalytic ability toward Rhodamine B in the range of visible light due to the 3D distribution of the TiO2 branches on the surface of the microspheres, which prompts the multireflection of photons. The absorption rate of photons is thereby tremendously enhanced. This is beneficial for the generation of hot electrons originating from the localized surface plasmonic resonance of Au nanorods, which can be used to both initiate the reaction and produce the photothermal effect. Hot electrons generated by a single Au nanorod in microspheres to initiate the degradation reaction can be as high as 2.5 times of those in the nanowires' counterpart. Moreover, the heating power of a single Au nanorod in microspheres reaches up to 4.4 times higher than that in nanowires, which further accelerates the degradation rate. The reaction pathway of visible-light-assisted RhB degradation catalyzed by Au/TiO2 microspheres goes through an initial N-deethylation process instead of the complete cycloreversion catalyzed by pure TiO2 microspheres under UV irradiation. This strategy of structure design for improved photon absorption, which achieves high degradation rate and photothermal effect, is promising for the development of novel photocatalysts. [ABSTRACT FROM AUTHOR]

• The surface uniformity of substrate was optimized toward sinter-resistant catalyst. • TiO 2 nanofibers were decorated with well-defined rutile nanorods as substrate. • 3 nm-Pt NPs were stabilized under sinter-promoting situations over 600 °C. • Pt NPs on the nanorods-decorated-TiO 2 nanofibers were active for soot oxidation. One of the most urgent concerns for supported catalysts is to enhance their thermal stability against sintering upon high temperatures (above 300 °C). In this work, we decorated the rough surface of TiO 2 nanofibers with a sheath of rutile nanorods to improve their surface uniformity and explored them as new reliable substrates to stabilize Pt nanoparticles without capping shell. During preparation, the surface-initiated grain growth facilitates the decorated TiO 2 crystals to transform into rutile nanorods, exposing rutile {1 1 1} and {1 1 0} facets. With the presence of TiO 2 nanofibers, these rutile nanorods were finely confined against coalescence and reconstruction upon 700 °C, offering reliable supports for stabilizing metal nanoparticles. Therefore, the diminished driving force for sintering enables the whole catalyst system to withstand temperatures up to 500 °C at an oxidative atmosphere. After calcination at 500 °C, the Pt on rutile nanorods-decorated-TiO 2 nanofibers exhibited nearly 3-times higher reaction rate constant (27.8 s−1·g−1·L−1) toward hydrogenation of 4-nitrophenol over those on unmodified TiO 2. Moreover, such a thermally stable catalyst was active for the oxidation of soot particulates, decreasing the conversion temperature and maintaining a small Pt size of 6.99 nm after the sinter-promoting exothermic oxidation. [ABSTRACT FROM AUTHOR]