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Shape-memory biomaterials, especially those stable against degradation, are attractive for applications in the biomedical fields, such as artificial bone scaffold material, artificial blood vessel ...

The direct transformation of external energy into mechanical work by the self-propelled motor inspires and promotes the development of miniaturized machines. Several strategies have been utilized to realize the self-driven motion, but in some cases multiple power sources are needed, and this would complicate the operation in diverse environments. In this regard, the dual-mode self-propelled system based on a single power source is highly desirable. In this work, single-light-actuated dual-mode propulsion at the liquid/air interface is realized by using flexible, superhydrophobic, and thermostable photothermal paper made from flexible ultralong hydroxyapatite nanowires, titanium sesquioxide (Ti2O3) particles, and poly(dimethylsiloxane) coating. The superhydrophobic surface enables the thermostable photothermal paper to float on the water surface spontaneously and significantly reduces the drag force. In the usual situation, the heat power produced by the photothermal effect is utilized to trigger the Marangoni propulsion. While the Marangoni effect is quenched in water containing the surfactant, the propulsion mode can be directly switched into the vapor-enabled propulsion mode by simply increasing the light power density. Particularly, the light-driven motion in a linear, curvilinear, or rotational manner can be realized by designing the self-propelled machines with appropriate shapes by using the processable photothermal paper. It is expected that the as-prepared dual-mode self-propelled, flexible, superhydrophobic, and thermostable photothermal paper-based devices have promising applications in various fields such as microrobots, biomedicine, and environmental monitoring.

Oxygen vacancy engineering is effective for improving the photoelectrochemical (PEC) performance of electrodes. However, such a protocol has not yet shown impressive success for ZnO photoanodes due...

Stimulus-responsive actuators that can respond to the external stimuli and convert external energy into dynamic movement behaviors are highly desired for many applications. Among various driving sc...

The frequent occurrence of oil spilling and industrial oily wastewater have serious negative effects on the marine ecosystem and human health. For this reason, high performance, effective, and cont...

Oriented, Crystalline Anatase TiO2 Nanorods on Transparent Conducting Electrodes Dong-Dong Qin,† Ying-Pu Bi,‡ Xin-Jian Feng, Wei Wang, Greg D. Barber, Ting Wang,† Yu-Min Song,† Xiao-Quan Lu,† and Thomas E. Mallouk* †Key Lab of Bioelectrochemistry and Environmental Analysis of Gansu, College of Chemistry and Chemical Engineering, The Northwest Normal University, Lanzhou, Gansu 730070, People’s Republic of China Department of Chemistry and Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, United States ‡National Engineering Research Center for Fine Petrochemical Intermediates, Lanzhou Institute of Chemical Physics, Chinese Acadamy of Sciences, Lanzhou, Gansu 730000, People’s Republic of China Suzhou Institute of Nano-Tech and Nano-Bionics (SINANO), Chinese Acadamy of Sciences, Suzhou, Jiangsu 215123, People’s Republic of China

The controlled growth of highly ordered, [211]-oriented FeOOH nanowire arrays on various substrates, such as Pt, W, Ti, and fluoride-doped tin oxide (FTO) glass, was achieved by a solvothermal method in aqueous acetonitrile solutions at 80-120 degrees C, following by annealing to form alpha-Fe2O3 nanowires with their [110] direction perpendicular to the substrate. Adjusting the reaction pH and temperature enables control of the nanowire length. In particular, the pH has a dramatic effect on the nanowire growth, with low pH resulting in the growth of longer wires because of the acid-catalyzed hydrolysis of acetonitrile. Photoactive hematite was prepared by diffusing Ti or Sn into the nanowires during thermal annealing. Processing parameters that influenced the photoelectrochemical performance of these nanowire arrays, including the annealing regime, temperature, and length of nanowires, are discussed in detail. The Ti- and Sn-doped one-dimensional [110)-oriented alpha-Fe2O3 nanowire arrays provide an effective pathway for electron transport, demonstrating increased photocurrents, up to 1.3 mA/cm(2) under air mass 1.5 global (AM 1.5G) illumination, in photoelectrochemical water oxidation.