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Hydrogen peroxide (H2O2) is a versatile oxidant that is clean, environmentally friendly and typically produced industrially via the anthraquinone oxidation (AO) method. As opposed to the highly polluting conventional ways, the visible light photocatalytic reaction is a viable method for achieving sustainable H2O2 generation. Herein, visible light active WO3–SnO2 nanocomposites (WSN) were synthesized through a facile process for H2O2 production. The nanoscale particles of WO3 and SnO2 exhibit crystalline and mesocrystalline states, respectively, in the composites and, which are uniformly dispersed and tightly bound, forming the unique heterostructures, providing strong visible light absorption and abundant substrate adsorption and reaction sites. The composite exhibited the highest apparent catalytic activity with a WO3 : SnO2 molar ratio of 1 : 1. Under visible light irradiation, the catalytic production of H2O2 by the composite is 30 times more efficient than that by its individual components. The n–n heterojunction formed by the combination of WO3 and SnO2 allows for the directional transfer of photogenerated electrons and holes, while SnO2 promotes the migration of electrons from the bulk to the surface of the catalyst, further enabling the spatial separation of the charge carriers and higher oxygen reduction efficiency of the catalyst. This work provides a new research idea for improving WO3-based photocatalysts for H2O2 production and also presents a new pathway for effective visible light-driven generation of H2O2. [ABSTRACT FROM AUTHOR]

A hierarchical CoS–nanoparticle/carbon nanofibrous composite composed of CoS nanoparticles conformably anchored on the carbon fibres was fabricated by using a natural cellulose substance (e.g., ordinary laboratory filter paper) as the scaffold as well as the carbon source, and was applied as a high-performance anodic material for lithium-ion batteries. The initial cellulose substance (filter paper) was first carbonized at 450 °C, and then treated by KOH at 800 °C to acquire the activated carbon fibres; thereafter, the CoS nanoparticles were deposited onto the activated carbon fibres through a hydrothermal process. Such a porous three-dimensional network structure of the resultant CoS/carbon nanofibrous material inherited from the original cellulose substance resulted in high lithium ion diffusion coefficient, fast electronic transport and fine pseudo-capacitive effect. The composite with 37.0 wt% of cobalt sulfide displayed a high initial specific capacity of 1137.3 mA h g−1 and a stable reversible capacity of 576.7 mA h g−1 after 200 cycles at a current density of 100 mA g−1. Owing to the high specific surface area and porous structure of the CoS–nanoparticle/carbon nanofibrous composite, it delivered superior electrochemical performance during the lithiation/delithiation progress when used as an anodic material for lithium-ion batteries. [ABSTRACT FROM AUTHOR]

Introducing the sophisticated morphologies and structures of natural substances into artificial materials provides a promising strategy for the fabrication of functional materials with tailored structures and functionalities. Herein, our recent advances achieved in the fabrication of hierarchically structured functional materials derived from natural cellulose substances (e.g., ordinary laboratory filter paper) for lithium-ion batteries are reviewed. The surface sol–gel process was employed to fabricate metal oxides (Sn, Ti, Fe, etc.), silica and silicon based nanocomposites by using the corresponding metal alkoxides as the precursors, which faithfully inherited the unique porous network structures of the initial cellulose substances. However, the nanomaterials synthesized as such are limited to the above-mentioned species due to the limitation of specific metal alkoxide precursors used. To break this limitation, specific polyoxometalate clusters were employed as the building blocks to be assembled onto the surfaces of cellulose nanofibres and eventually to obtain the corresponding molybdenum based nanomaterials with three-dimensional porous network structures and specific properties. These cellulose derived nanocomposites exhibit improved lithium storage capacities and cycling stabilities when applied as anodic materials for lithium-ion batteries, resulting from the unique hierarchically porous network structures inherited from the initial cellulose substance and the strong synergistic interactions among the components contained therein. [ABSTRACT FROM AUTHOR]

Anatase phase titanium dioxide (titania) is a potential anodic material for lithium-ion batteries (LIBs), although a serious drawback is its low electrical conductivity. As an attempt to address this issue, a new hierarchically structured nanotubular anatase-titania/indium-tin-oxide (titania/ITO) composite was fabricated. Nanotubular structured anatase titania with a tube wall thickness of ca. 10 nm was firstly synthesized by employing a natural cellulose substance (ordinary laboratory filter paper) as the structural template, and a thin layer of ITO with a thickness of ca. 15 nm composed of fine ITO crystallites (particle sizes ca. 5 nm) was deposited by means of a solvothermal process. When this composite was utilized as an anodic material for LIBs, it delivered a high initial discharge capacity of 1773.4 mA h g−1 and a stable discharge capacity of 298.6 mA h g−1 after 120 charge/discharge processes cycled at 1 C. The unique hierarchical structure of the composite reduced the diffusion length for both electronic and ionic transport, improved the electrode–electrolyte contact area, and enhanced the accommodation of volume expansion and constriction during the lithium ion insertion/extraction process. Hence, improved electrochemical performances such as high reversible capacity, good rate performance and high cycling stability were achieved. [ABSTRACT FROM AUTHOR]

Photosystem II (PSII), as the only enzyme to catalyze the light-induced water oxidation reaction in the natural photosynthesis system, is introduced to fabricate artificial solar conversion systems with an intensive photo-to-current efficiency to convert solar energy into electrical power. In this research, we report a hybrid photo-bioelectrochemical system consisting of PSII isolated from spinach leaves that is co-assembled in nanotubular indium–tin oxide (ITO) multilayer films pasted on the commercial ITO substrate as a photoanode, which presents enhanced photocurrent responses as high as 2.4 μA cm−2 (mediator-free) and 39 μA cm−2 (with mediator) under white light irradiation (λ ＜ 800 nm) using a xenon lamp as the light source. In this photoanode system, the three-dimensional (3D) hierarchical porous nanotubular ITO film was synthesized through a layer-by-layer (LBL) self-assembly process using a natural cellulose substance (e.g., filter paper) as a template. The specific structure, and good optical and electrical properties of the hierarchical nanotubular ITO allow for an increased protein loading as high as 166 pmol PSII cm−2 and an enhanced photocurrent by about 78 times compared with the bare PSII photoanode. This biomimetic template fabrication method of ITO materials with unique morphologies and desirable properties provides an effective assembly strategy for PSII-based hybrid photoanode systems for solar energy conversion. [ABSTRACT FROM AUTHOR]

A bio-inspired nanofibrous silicon/carbon composite composed of a thin silicon layer consisting of fine silicon nanocrystallites conformally coated on carbon nanofibers was prepared by employing a natural cellulose substance (e.g. ordinary laboratory filter paper) as both a scaffold and a carbon source. The current synthetic method results in much more uniform and complete silicon coating on the carbon nanofibers. And the thickness of the silicon layer in the composite can be facilely controlled. When used as an anode material for lithium-ion batteries, the composite showed improved electrochemical performances due to the three-dimensional porous network structure of the carbon fiber scaffold and the thin silicon layer. Such a silicon/carbon composite with 25.7 wt% of silicon content and a silicon layer with a thickness of ca. 40 nm exhibited good cycling stability with a specific capacity of 750.6 mA h g−1 after 150 charge/discharge cycles at a current density of 100 mA g−1. Further coating of an additional carbon layer or depositing silver nanoparticles onto the surfaces of the silicon/carbon nanofibers resulted in much more improved electrochemical performances, and specific capacities of 775.3 and 1018.7 mA h g−1 were delivered by the corresponding composites resulting after 150 cycles at 100 mA g−1, respectively. [ABSTRACT FROM AUTHOR]

The fabrication of artificial photosynthetic systems to convert solar energy into electrical power is of great importance to meet human needs for energy; photosystem II (PSII), the core enzyme for water splitting in natural solar energy conversion processes can be introduced for this purpose. However, there remain significant challenges in the facile preparation of such semi-artificial photoanode systems with enhanced photocurrent responses. Herein we report a hybrid photoanode system consisting of PSII from spinach integrated into an indium-tin oxide electrode modified with nanotubular titania that is synthesized by using cellulose paper as a scaffold. This electrode provides a well-defined hierarchical nanostructure for protein loading, and the fine titania nanocrystals facilitate electron transfer from PSII to the electrode. The resulting semiconductor–protein hybrid photo-bioelectrochemical system enhances direct electron transfer (1.3 μA cm−2) and mediated electron transfer (10.6 μA cm−2) photocurrents. [ABSTRACT FROM AUTHOR]

A bio-inspired nanofibrous polypyrrole/silicon composite derived from natural cellulose substance was synthesized. Due to its unique porous network structure and PPy coating on the silicon fibres, it showed improved reversible capacity, cyclability and rate capability upon long-term charge/discharge cycling when employed as an anode material for lithium-ion batteries. [ABSTRACT FROM AUTHOR]

Deposition of silver nanoparticles (Ag-NPs) onto the surfaces of titania/carbon nanocomposite fibres, which were fabricated by employing a natural cellulose substance (commercial laboratory filter paper) as both the scaffold and carbon source, resulted in a new nanofibrous ternary Ag-NP/titania/carbon composite material, which was employed as an anode material for lithium ion batteries, which showed improved electrochemical performances compared with titania, carbon and titania/carbon hybrid counter materials. For such a composite with 22.48 wt% of silver and Ag-NPs with the size of 5–10 nm, the initial discharge capacity was 1323 mA h g−1 at a current density of 100 mA g−1, and it showed a stable capacity of 320 mA h g−1 after 150 charge–discharge cycles. It was found that the electrochemical performances of the anode material got better with the increase of the silver content in the composites. Due to the enhanced electric conductivity caused by the silver nanoparticles, as well as the unique three-dimensional cross-linked network structure of the composite, the anode performances in terms of the capacity, cycling stability and rate capacity are significantly improved. [ABSTRACT FROM AUTHOR]

We have developed an approach to duplicate the structure of a natural cellulose substance (commercial laboratory filter paper) with titanium metal. A nanometer precise anatase titania replica of filter paper was converted into alpha phase (hcp) titanium by a calciothermic reduction process using calcium chloride as a molten salt. The resulting fibrous titanium metal consists of hierarchical structured fine titanium fibres as duplicates of the cellulose fibres of the initial filter paper. [ABSTRACT FROM AUTHOR]

The non-toxic and biocompatible cellulose possesses nonspecific binding properties for many protein molecules. But its abundant inter- and intra-molecular hydrogen bonds induce spontaneous self-assembly of cellulose into a random fibrous morphology and cellulose film coating is usually just available for two-dimensional flat substrates, which severely limits its protein adsorption performance. In this study, direct self-assembly of an ultrathin cellulose film on hybrid polyelectrolyte multilayer pre-coated pore surfaces of an anodic aluminum oxide membrane was achieved through the dissolution and precipitation of cellulose from N-methylmorpholine oxide solution. Each pore channel surface pre-coated with a uniform polyelectrolyte hybrid layer (thickness ∼5.0 nm) was covered by a cellulose film (∼15.0 nm) consisting of dense cellulose nanoparticles with a diameter of 5.5 ± 1.4 nm. The three-dimensional porous structure of the aluminum oxide membrane was well-preserved and micrometre-long flexible nanotubes with an average outer diameter of ∼200 nm were obtained after further aluminum oxide template dissolution treatment in an acidic environment. Moreover, the cellulose film coated pore channel surfaces presented sufficient hydrogen bonds and exhibited a high adsorption capacity rate of ∼1.45 mg m−2 for superoxide dismutase. This facile cellulose deposition approach enabled ultrathin cellulose film coating on three-dimensional structured substrates for enhanced adsorption performance for protein molecules. [ABSTRACT FROM AUTHOR]

The reversible self-assembly of ferritin molecules into stable size-tailored ferritin microspheres was achieved in 1-octanol, and microrods consisting of ferritin microspheres were prepared by the porous polycarbonate membrane templated deposition of these ferritin microspheres. [ABSTRACT FROM AUTHOR]

Uniform ultrathin titania/chitosan composite films were coated on the cellulose microfibril bundles of natural cellulose substance (common commercial filter paper) by a layer-by-layer self-assembly process. Relying on the strong chelating ability of chitosan for metal ions, silver ions were abundantly adsorbed on the titania/chitosan composite film coated cellulose substance and were thereafter in situ reduced to silver nanoparticles (Ag-NPs) under UV irradiation. As such, hybrid cellulose/titania/chitosan/Ag-NP composite materials were obtained, which feature the same hierarchically fibrous structure as the initial cellulose substance. Meanwhile, the hybrid fibres in the composite materials exhibit a cable-like core–shell structure, displaying a cellulose microfibril bundle core as well as a nanometer-thick titania/chitosan/Ag-NP composite film shell with Ag-NPs (4–20 nm in diameter) well distributed. The antibacterial activities of the titania/chitosan/Ag-NP composite film coated cellulose materials were evaluated against both Gram-positive and Gram-negative bacteria, and the materials as such disinfected almost all the inoculated bacteria due to the intrinsic biocidal effect of titania composition, positively charged chitosan component and high loading content of Ag-NPs with small sizes, showing excellent antibacterial activities. [ABSTRACT FROM AUTHOR]

Hierarchical nanofibrous titania–carbon composite material deposited with silver nanoparticles derived from a natural cellulose substance (filter paper) was designed and fabricated. ICP-MS analysis showed that the content of deposited silver nanoparticles is as high as (9.5 ± 0.1) wt%, and TEM observation revealed that the deposited silver nanoparticles are uniform with small sizes (∼5 nm). The antibacterial activity of the hierarchical nanofibrous titania–carbon composite material deposited with silver nanoparticles was tested against both Gram-positive and Gram-negative bacteria and the material exhibited high inactivation of bacteria due to the synergistic effect of porous carbon nanofibres, anatase titania ultrathin film coating and high loading content of silver nanoparticles with small sizes. [ABSTRACT FROM AUTHOR]

Free-standing microtubes with diameters of 250–300 nm composed of polystyrene microspheres were fabricated by a facile self-assembly approach templated with porous alumina membranes. A polycation (polyethyleneimine, PEI) layer was deposited onto the surfaces of the alumina membrane channels to change the surface charge from negative to positive, and polystyrene microspheres whose surface was modified with carboxyl groups were subsequently immobilized onto the channel walls in basic solution through electrostatic interaction. Successive annealing of the sample was carried out to make the adjacent polystyrene microspheres coalesce slightly, and after dissolving the alumina membrane, free-standing latex microtubes were obtained. [ABSTRACT FROM AUTHOR]

Cellulose materials with photo-reversible wettability were prepared by self-assembling of 7-[(trifluoromethoxyphenylazo)-phenoxy] pentanoic acid (CF3AZO) monolayer onto titania ultrathin film pre-coated nanofibre surfaces of commercial laboratory filter paper. The as-prepared CF3AZO monolayer modified filter paper approached superhydrophobicity, and it transited to extremely hydrophilic state after being exposed to UV light (λ= 365 nm) irradiation, and the original surface wettability recovered after dark storage. The conformational transformation of the photo-sensitive CF3AZO molecules during UV irradiation and dark storage was related to the reversible wettability. A titania gel layer deposited on the nanofibre surfaces of filter paper, compared with silica gel layer, was more active for assembly of CF3AZO molecules, and the hydroxyl moieties implanted on the surface of titania gel layer during UV irradiation and their substitution by oxygen in the dark demonstrated a synergic effect on tailoring surface wettability. [ABSTRACT FROM AUTHOR]

A hierarchical luminescent cellulose sheet was fabricated viaself-assembly of cadmium selenide (CdSe) nanoparticles capped with trioctylphosphine oxide (TOPO) and 1-hexadecylamine (HDA) onto ultrathin titania film pre-coated cellulose nanofibres of bulk natural cellulose substance (common commercial filter paper). Each cellulose nanofibre of the filter paper was firstly coated with nanometre-thick titania film by means of the surface sol–gel process, followed by alternative deposition of self-assembled layers of stearic acid (SA) and TOPO/HDA capped CdSe nanoparticles, giving a filter paper/titania/SA/(CdSe/SA) composite luminescent sheet possessing stable and well-defined green fluorescence. SEM and TEM observations showed that the resulting luminescent sheet retained the hierarchical structures and morphologies of the initial cellulose substance; meanwhile, the CdSe nanoparticles were anchored on the nanofibre surfaces within SA thin layers through the hydrophobic interaction between the alkyl chains of the surface ligands of CdSe nanoparticles and SA molecules. UV-vis and photoluminescence spectra indicated that the resulting luminescent sheet showed similar characteristic absorption and emission properties as those of the original CdSe nanoparticles. The current approach provides a facile shortcut to fabricate bulk luminescent materials that inherit the mechanical behaviour of cellulose substances and simultaneously possess designed luminescent properties. [ABSTRACT FROM AUTHOR]

Hierarchical nanotubular TiN was prepared by magnesiothermic reduction of titania replicas of a cellulose substance (filter paper), which possessed high surface area (31.4 m(2) g(-1)), and was demonstrated to be a promising electrode material due to its electrochemical performances.

Hierarchical nanotubular rutile titania material was fabricated by facile flame burning of ultrathin titania gel film coated cellulose nanofibres of commercial cellulose substance (filter paper), which possesses efficient photocatalytic performance for degradation of organic dye (methylene blue) under ultraviolet irradiation., (This journal is © The Royal Society of Chemistry 2011)

Bio-inspired superparamagnetic hierarchical material which possesses significant thermal stability and superparamagnetic property was fabricated by core reconstruction of silica thin film coated ferritin molecules that were immobilized on the surface of natural cellulose nanofibres of common commercial filter paper.

Immobilization of ruthenium dye or mercaptosilane monolayer onto metal oxide ultrathin film pre-coated cellulose nanofibres of natural cellulose substances yielded colorimetric sensing materials with high sensitivity and selectivity as well as good reversibility, and trapping materials with high efficiency for detection and adsorption of Hg(2+) ions in aqueous media.

Nanofibrous platinum sheets with a thickness of one to a few tens of nanometres were prepared over the submicron pores of polymer substrates by using long and rigid cadmium hydroxide nanostrands as templates, and these free-standing sheets gave metallic conductivity that varied greatly with the thickness.

Latex nanoparticles were packed inside nanometer-thick titania/polymer composite nanotubules templated by porous alumina membrane, to give free-standing particle-in-tubing "micro-beanpods" after removal of the template membrane.

Astonishingly uniform polypyrrole nanocoating on morphologically complex cellulosic substances was achieved without disrupting the hierarchical network structures of individual cellulose fibers by means of polymerization-induced adsorption.

A synthetic method that can fine tune the amount of chemically accessible organic functional groups on the pore surface of MCM-41 type mesoporous silica nanosphere (MSN) materials has been developed by electrostatically matching various anionic organoalkoxysilanes with the cationic cetyltrimethylammonium bromide micelles in a base-catalyzed condensation reaction of tetraethoxysilane.

A hierarchical hybrid of gold nanoparticles and titania nanotubes with high metal loading was prepared by a one-pot approach using a natural cellulosic substance as template. Gold nanoparticles were uniformly anchored onto titania nanotubes, and particle fusion at high temperature was suppressed by surface coating with an ultrathin titania layer.

An ultrathin titania film with molecular-sized cavities was synthesized by treating a ca. 8 nm thick (TiO2)3(dendrimer)(TiO2)2 sandwich film with activated oxygen gas.