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Bismuth vanadate ranks among the most promising photoanodes for photoelectrochemical water splitting. Nonetheless, slow charge separation and transport are key barriers to its photoefficiency. Here, we present a co-doping strategy that significantly improves the charge separation performance of BVO. Under standard one sun illumination, the Fe-N co-doped BVO photoanode (Fe-N-BVO) by N-coordinated Fe precursor reaches a record photocurrent density of 7.01 mA cm-2 at 1.23 V vs RHE after modified a surface co-catalyst. By contrast, much lower photocurrent density is obtained for the N-doped and Fe-doped BVO with separated N and Fe precursors. The detailed characterizations show that the high activity of the Fe-N-BVO is attributed to the enhanced photo-induced bulk charge separation and the accelerated surface water oxidation kinetics. XPS, EXAFS and DFT calculations clearly show that, instead of formation of deep trapping state in the individually doped BVO, the co-doping of Fe-N into BVO generates Fe-based electronic states just below the bottom of conduction band and N-derived states just above the top of valence band. Such modulations in electronic structure enable the efficient trap of the electrons and holes to enhance the separation of photo-induced carriers, but hinder the charge recombination originated from the deep trapping sites., (© 2024 Wiley‐VCH GmbH.)

Artificial photosynthesis, harnessing solar energy to convert CO 2 into hydrocarbons, presents a promising solution for climate change and energy scarcity. However, photocatalytic CO 2 reduction often terminates at the CO stage due to limited electron transfer capacity, hindering the formation of higher-energy hydrocarbons such as CH 4 . This study introduces, for the first time, an in-situ atmosphere regulation strategy, refined from molecular imprinting methodologies, using dynamically reacting molecules to precisely engineer photocatalytic surface sites for selective *CO adsorption and hydrogenation in CO 2 -to-CH 4 conversion. Specifically, the single-atom Cu catalyst (Cu-SA-CO) is prepared by anchoring single-atom Cu onto defective TiO 2 substrates (Cu-SA-CO) under a CO reduction atmosphere. Under illumination, the catalyst exhibited outstanding CH 4 selectivity (almost 100%) and productivity (58.5 µmol g -1  h -1 ). Mechanistic investigations reveal that the coordination environment of the Cu single atoms is significantly affected by dynamically reacting molecules (CO and *CH x O) during synthesis, leading to a Ti-Cu-O structure. The structure, with the synergistic interaction between Cu single atoms and oxygen defects, significantly enhances *CO adsorption and hydrogenation, thereby promoting the formation of methane. This work pioneers the use of dynamically reactive molecules as imprinted templates to tune photocatalytic CO 2 reduction selectivity, providing a novel avenue for designing efficient photocatalysts., (© 2024 Wiley‐VCH GmbH.)

In photocatalysis, the resulted heat by the relaxation of most of incident light no longer acts as the industrially favorite driving force back to the target photo-reaction due to more or less the negative relation between photocatalytic efficiency and temperature. Here, we reported a visible light-sensitized protocol that completely reversed the negatively temperature-dependent efficiency in photo-driven CO2 methanation with saturated water vapor. Uniform Pt/N-TiO2/PDI self-assembly material decisively injects the excited electron of PDI sensitizer into N-TiO2 forming Ti-H hydride which is crucially temperature-dependent nucleophilic species to dominate CO2 methanation, rather than conventionally separated and trapped electrons on the conductor band. Meanwhile, the ternary composite lifts itself temperature from room temperature to 305.2 °C within 400s only by the failure excitation upon simulated sunlight of 2.5 W/cm2, and smoothly achieves CO2 methanation with a record number of 4.98 mmol g-1 h-1 rate, compared to less than 0.02 mmol g-1 h-1 at classic Pt/N-TiO2/UV photocatalysis without PDI sensitization. This approach can reuse ~53.9% of the relaxed heat energy from the incident light thereby allow high-intensity incident light as strong as possible within a flowing photo-reactor, opening the most likely gateways to industrialization., (© 2024 Wiley‐VCH GmbH.)

Electrochemical reduction of CO 2 and nitrate offers a promising avenue to produce valuable chemicals through the using of greenhouse gas and nitrogen-containing wastewater. However, the generally proposed reaction pathway of concurrent CO 2 and nitrate reduction for urea synthesis requires the catalysts to be both efficient in both CO 2 and nitrate reduction, thus narrowing the selection range of suitable catalysts. Herein, we demonstrate a distinct mechanism in urea synthesis, a tandem NO 3 - and CO 2 reduction, in which the surface amino species generated by nitrate reduction play the role to capture free CO 2 and subsequent initiate its activation. When using the TiO 2 electrocatalyst derived from MIL-125-NH 2 , it intrinsically exhibits low activity in aqueous CO 2 reduction, however, in the presence of both nitrate and CO 2 , this catalyst achieves an excellent urea yield rate of 43.37 mmol ⋅ g -1  ⋅ h -1 and a Faradaic efficiency of 48.88 % at -0.9 V vs. RHE in a flow cell. Even at a low CO 2 level of 15 %, the Faradaic efficiency of urea synthesis remains robust at 42.33 %. The tandem reduction procedure was further confirmed by in situ spectroscopies and theoretical calculations. This research provides new insights into the selection and design of electrocatalysts for urea synthesis., (© 2024 Wiley-VCH GmbH.)

We report a light-irradiation method to control the synchronous nucleation of a donor-acceptor (D-A) fluorophore for growing highly uniform single-crystalline microrods, which is in sharp contrast to the prevailing methods of restricting spontaneous nucleation and additionally adding seeds. The D-A fluorophore was observed to undergo photoinduced electron transfer to CrCl 3 , leading to the generation of HCl and the subsequent protonation of the D-A fluorophore. By intensifying photoirradiation or prolonging its duration, the concentration of protonated D-A fluorophores can be rapidly increased to a high supersaturation level. This results in the formation of a controlled number of nuclei in a synchronous manner, which in turn kickstart the epitaxial growth of protonated D-A fluorophores towards uniform single-crystalline microrods of controlled sizes. The light-regulated synchronous nucleation and uniform growth of microrods are a unique phenomenon that can only be achieved by specific Lewis acids, making it a novel probing method for sensitively detecting strong Lewis acids such as chromium chloride., (© 2024 Wiley-VCH GmbH.)

Photocatalytic conversion of CO 2 and H 2 O into fuels and oxygen is a highly promising solution for carbon-neutral recycling. Traditionally, researchers have studied CO 2 reduction and H 2 O oxidation separately, overlooking potential synergistic interplay between these processes. This study introduces an innovative approach, spatial synergy, which encourages synergistic progress by bringing the two half-reactions into atomic proximity. To facilitate this, we developed a defective ZnIn 2 S 4 -supported single-atom Cu catalyst (Cu-SA/D-ZIS), which demonstrates remarkable catalytic performance with CO 2 reduction rates of 112.5 μmol g -1  h -1 and water oxidation rates of 52.3 μmol g -1  h -1 , exhibiting a six-fold enhancement over D-ZIS. The structural characterization results indicated that the trapping effect of vacancy associates on single-atom copper led to the formation of an unsaturated coordination structure, Cu-S 3 , consequently giving rise to the Cu Zn 'V S ⋅⋅V Zn " defect complexes. FT-IR studies coupled with theoretical calculations reveal the spatially synergistic CO 2 reduction and water oxidation on Cu Zn 'V S ⋅⋅V Zn ", where the breakage of O-H in water oxidation is synchronized with the formation of *COOH, significantly lowering the energy barrier. Notably, this study introduces and, for the first time, substantiates the spatial synergy effect in CO 2 reduction and H 2 O oxidation through a combination of experimental and theoretical analyses, providing a fresh insight in optimizing photocatalytic system., (© 2023 Wiley-VCH GmbH.)

High-efficient photoelectrocatalytic direct ammonia oxidation reaction (AOR) conducted on semiconductor photoanodes remains a substantial challenge. Herein, we develop a strategy of simply introducing ppm levels of Cu ions (0.5-10 mg/L) into NH 3 solutions to significantly improve the AOR photocurrent of bare BiVO 4 photoanodes from 3.4 to 6.3 mA cm -2 at 1.23 V RHE , being close to the theoretical maximum photocurrent of BiVO 4 (7.5 mA cm -2 ). The surface charge-separation efficiency has reached 90 % under a low bias of 0.8 V RHE . This AOR exhibits a high Faradaic efficiency (FE) of 93.8 % with the water oxidation reaction (WOR) being greatly suppressed. N 2 is the main AOR product with FEs of 71.1 % in aqueous solutions and FEs of 100 % in non-aqueous solutions. Through mechanistic studies, we find that the formation of Cu-NH 3 complexes possesses preferential adsorption on BiVO 4 surfaces and efficiently competes with WOR. Meanwhile, the cooperation of BiVO 4 surface effect and Cu-induced coordination effect activates N-H bonds and accelerates the first rate-limiting proton-coupled electron transfer for AOR. This simple strategy is further extended to other photoanodes and electrocatalysts., (© 2023 Wiley-VCH GmbH.)

This study reports the design of a donor-acceptor (D-A) molecule with two fluorene units on each side of a benzothiadiazole moiety, which allows multiple intermolecular interactions to compete with one another so as to induce the evolution of the metastable 2D platelets to the stable 2D platelets during the self-assembly of the D-A molecule. Importantly, the living seeded self-assembly of metastable and stable 2D structures with precisely controlled sizes can be conveniently achieved using an appropriate supersaturated level of a solution of the D-A molecule as the seeded growth medium that can temporarily hold the almost-proceeding spontaneous nucleation from competing with the seeded growth. The stable 2D platelets with smaller area sizes exhibit higher sensitivity to gaseous dimethyl sulfide, illustrating that the novel living self-assembly method provides more available functional structures with controlled sizes for practical applications. The key finding of this study is that the new living methodology is separated into two independent processes: the elaborate molecular design for various crystalline structures as seeds and the application of a supersaturated solution with appropriate levels as the growth medium to grow the uniform structures with controlled sizes; this would make convenient and possible the living seeded self-assembly of rich 1D, 2D, and 3D architectures., (© 2023 Wiley-VCH GmbH.)

Herein we report the vital role of spin polarization in proton-transfer-mediated water oxidation over a magnetized catalyst. During the electrochemical oxygen evolution reaction (OER) over ferrimagnetic Fe 3 O 4 , the external magnetic field induced a remarkable increase in the OER current, however, this increment achieved in weakly alkaline pH (pH 9) was almost 20 times that under strongly alkaline conditions (pH 14). The results of the surface modification experiment and H/D kinetic isotope effect investigation confirm that, at weakly alkaline pH, during the nucleophilic attack of Fe IV =O by molecular water, the magnetized Fe 3 O 4 catalyst polarizes the spin states of the nucleophilic attacking intermediates. The spin-enhanced singlet O-H cleavage and triplet O-O bonding occur synergistically, which promotes the O 2 generation more significantly than the strongly alkaline case involving only spin-enhanced O-O bonding., (© 2023 Wiley-VCH GmbH.)

Herein, we fabricated a π-π stacking hybrid photocatalyst by combining two two-dimensional (2D) materials: g-C 3 N 4 and a Cu-porphyrin metal-organic framework (MOF). After an aerobic photocatalytic pretreatment, this hybrid catalyst exhibited an unprecedented ability to photocatalytically reduce CO 2 to CO and CH 4 under the typical level (20 %) of O 2 in the air. Intriguingly, the presence of O 2 did not suppress CO 2 reduction; instead, a fivefold increase compared with that in the absence of O 2 was observed. Structural analysis indicated that during aerobic pretreatment, the Cu node in the 2D-MOF moiety was hydroxylated by the hydroxyl generated from the reduction of O 2 . Then the formed hydroxylated Cu node maintained its structure during aerobic CO 2 reduction, whereas it underwent structural alteration and was reductively devitalized in the absence of O 2 . Theoretical calculations further demonstrated that CO 2 reduction, instead of O 2 reduction, occurred preferentially on the hydroxylated Cu node., (© 2023 Wiley-VCH GmbH.)

Prospects in light-driven water activation have prompted rapid progress in hydrogenation reactions. We describe a Ni 2+ -N 4 site built on carbon nitride for catalyzed semihydrogenation of alkynes, with water supplying protons, powered by visible-light irradiation. Importantly, the photocatalytic approach developed here enabled access to diverse deuterated alkenes in D 2 O with excellent deuterium incorporation. Under visible-light irradiation, evolution of a four-coordinate Ni 2+ species into a three-coordinate Ni + species was spectroscopically identified. In combination with theoretical calculations, the photo-evolved Ni + is posited as HO-Ni + -N 2 with an uncoordinated, protonated pyridinic nitrogen, formed by coupled Ni 2+ reduction and water dissociation. The paired Ni-N prompts hydrogen liberation from water, and it renders desorption of alkene preferred over further hydrogenation to alkane, ensuring excellent semihydrogenation selectivity., (© 2023 Wiley-VCH GmbH.)

The sluggish H 2 O oxidation kinetics on photoanodes severely obstructs the overall solar-to-energy efficiency of photoelectrochemical (PEC) cells. Herein, we find a 10 to 55-fold increase of photocurrent by conducting ammonia oxidation reaction (AOR) on hematite (α-Fe 2 O 3 ) photoanodes under near-neutral pH (9-11) and moderate applied potentials (1.0-1.4 V RHE ) compared to H 2 O oxidation. By rate law analysis and operando spectroscopic studies, we confirm the non-radical nucleophilic attack of NH 3 molecules on high-valent surface Fe-O species (e.g., Fe IV =O) and Fe-N species that produces NO x - and N 2 , respectively, which overwhelms the nucleophilic attack of H 2 O on surface Fe IV =O and contributes to a high Faradaic efficiency of above 80 % for AOR. This work reveals a novel non-radical nucleophilic attack strategy, which is significantly different from the conventional indirect radical-mediated AOR mechanism, for the rational design of high-performance AOR photoelectrocatalysts., (© 2022 Wiley-VCH GmbH.)

Constructing heterostructures have been demonstrated as an ideal strategy for boosting charge separation on plasmonic photocatalysts, but the detailed interface charge transfer mechanism remains elusive. Herein, that authors fabricate plasmonic Au and metal-organic frameworks (MOFs, NH 2 -MIL-125 and MIL-125 used in this work) heterostructures and explore the interface charge transfer mechanism by in situ electron paramagnetic resonance (EPR) spectroscopy and electrochemical measurements. The plasmon-excited hot electrons on Au can transfer across the Au/MOF interface and be captured by the coordinatively unsaturated sites of secondary building units (Ti 8 O 8 (OH) 4 cluster) of the MOF structure, and the plasmon-excited hot holes on Au tend to transfer to and be trapped at the functionalized organic ligand (1,4-benzenedicarboxylate-NH 2 ). The spatially separated hot electrons and holes exhibit boosted the photocatalytic activity for chromium (VI) reduction and selective benzyl alcohol oxidation. This work illustrates the advantage of the versatile functionalization of MOF structures enabling molecular-level manipulation of interface charge transfer on plasmonic photocatalysts., (© 2022 Wiley-VCH GmbH.)

Regulating the distribution of reactive oxygen species generated from H 2 O 2 activation is the prerequisite to ensuring the efficient and safe use of H 2 O 2 in the chemistry and life science fields. Herein, we demonstrate that constructing a dual Cu-Fe site through the self-assembly of single-atomic-layered Cu 5 nanoclusters onto a FeS 2 surface achieves selective H 2 O 2 activation with high efficiency. Unlike its unitary Cu or Fe counterpart, the dual Cu-Fe sites residing at the perimeter zone of the Cu 5 /FeS 2 interface facilitate H 2 O 2 adsorption and barrierless decomposition into ⋅OH via forming a bridging Cu-O-O-Fe complex. The robust in situ formation of ⋅OH governed by this atomic-layered catalyst enables the effective oxidation of several refractory toxic pollutants across a broad pH range, including alachlor, sulfadimidine, p-nitrobenzoic acid, p-chlorophenol, p-chloronitrobenzene. This work highlights the concept of building a dual catalytic site in manipulating selective H 2 O 2 activation on the surface molecular level towards efficient environmental control and beyond., (© 2022 Wiley-VCH GmbH.)

The design of sensor array members with synchronous fluorescence and photostability is crucial to the reliable performance of sensor arrays in multiple detections and their service life. Herein, a strategy is reported for achieving synchronous fluorescence and photostability on two coassemblies fabricated from carbazole-based energy donor hosts and a photostable energy acceptor. When a small number of the same energy acceptors are embedded into two carbazole-based energy donor hosts, the excitation energy of the donors can be efficiently harvested by the acceptors through long-range exciton migration and Förster resonance energy transfer (FRET) to achieve synchronous fluorescence and photostability in both coassemblies. More intriguingly, the synchronous photostability substantially improves the multiple discrimination capacity (e.g., 10 times more discriminations of TNT in two coassemblies have been achieved compared to the sensor array comprising two individual donor assemblies) and the working lifetime of the sensor array. The concept of optical synchronization (i.e., emission and photostability) of sensor array members can be extended to other sensor arrays for the steady multiple detection of certain hazardous chemicals., (© 2021 The Authors. Advanced Science published by Wiley-VCH GmbH.)

In this work, photostable coassemblies from a nonphotostable fluorene oligomer (the energy donor) and a photostable oligomer (the energy acceptor) are fabricated. Long-range exciton migration over a net distance of about 370 energy-donor molecules to energy acceptors is demonstrated in such coassemblies. The fast and long energy migration allows harvesting of the excitation energy of energy donors by embedding a small number of energy acceptors for photostability enhancement. Importantly, embedding a small number of energy acceptors in coassemblies causes a negligible negative influence on the electron donation of energy donors that are desired in practical applications. The advantages of the coassemblies fabricated, that is, high photostability without disrupting the electron donation of energy donors, are well illustrated in fluorescence detection of trace explosives where prolonged working life and improved detection capacity are achieved., (© 2020 Wiley-VCH GmbH.)

Current plasmonic photocatalysts are mainly based on noble metal nanoparticles and rarely work in the infrared (IR) light range. Herein, cost-effective Bi 2 O 3-x with oxygen vacancies was formed in situ on commercial bismuth powder by calcination at 453.15 K in atmosphere. Interestingly, defects introduced into Bi 2 O 3-x simultaneously induced a localized surface plasmon resonance (LSPR) in the wavelength range of 600-1400 nm and enhanced the adsorption for CO 2 molecules, which enabled efficient photocatalysis of CO 2 -to-CO (ca. 100 % selectivity) even under low-intensity near-IR light irradiation. Significantly, the apparent quantum yield for CO evolution at 940 nm reached 0.113 %, which is approximately 4 times that found at 450 nm. We also showed that the unique LSPR allows for the realization of a nearly linear dependence of photocatalytic CO production rate on light intensity and operating temperature. Finally, based on an IR spectroscopy study, an oxygen-vacancy induced Mars-van Krevlen mechanism was proposed to understand the CO 2 reduction reactions., (© 2020 Wiley-VCH GmbH.)

Real-time, high signal intensity, and prolonged detection is challenging because of the rarity of fluorophores with both high photostability and luminescence efficiency. In this work, new donor-acceptor (D-A) molecules for overcoming these limitations are reported. A hybridized local and an intramolecular charge-transfer excited state is demonstrated to afford high photoluminescence efficiency of these D-A molecules in solution (≈100%). The twisted molecular structure and bulky alkyl chains effectively suppress π - π and dipole-dipole interactions, enabling high luminescence efficiency of 1 and 2 in the solid state (≈94% and 100%). Furthermore, two D-A aggregates exhibit high photostability as evidenced by 4% and 8% of the fluorescence decreasing after 6 h of continuous irradiation in air, which is in sharp contrast to ≈95% of fluorescence decreasing in a reference compound. Importantly, with these molecules, ultrasensitive detection of sulfur mustard (SM) with a record limit of 10 ppb and selective detection of SM in complex matrices are achieved., Competing Interests: The authors declare no conflict of interest., (© 2021 The Authors. Advanced Science published by Wiley‐VCH GmbH.)

The light-driven crawling of a molecular crystal that can form three phases, (α, β, and γ) is presented. Laser irradiation of the molecular crystal can generate phase-dependent transient elastic lattice deformation. The resulting elastic lattice deformation that follows scanning irradiation of a laser can actuate the different phases of molecular crystal to move with different velocity and direction. Because the γ phase has a large Young's modulus (ca. 26 GPa), a force of 0.1 μN can be generated under one laser spot. The generated force is sufficient to actuate the γ-formed molecular crystals in a wide dimensional range to move longitudinally at a velocity of about 60 μm min -1 , which is two orders of magnitude faster than the α and β phases., (© 2020 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The controlled formation of complex and functional 1-, 2-, and 3D hierarchical assemblies from molecular building blocks represents a key current challenge. Herein, we report the use of a seeded growth approach for a series of perylenediimide-based molecules (PDIs 1-4) to access otherwise inaccessible self-assembly pathways that yield complex hierarchical structures. The key to the new approach is to use hetero-seeds which possess a different composition and morphology from that of the molecular building block. For example, a nanotube seed (from PDI 3) and a microribbon seed (from PDI 4) were found to initiate different self-assembly pathways for PDI 1, which normally assembles to yield nanocoils. This led to the formation of unprecedented 3D scroll-like and scarf-like hierarchical nanostructures, respectively. Also, the hetero-seeds from PDI 3 initiate hidden self-assembly pathways of PDI 2 to generate 1D tubular heterojunctions. Significantly, this new strategy offers new opportunities to create emergent and functional hierarchical and complex structures from small molecule precursors., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Manipulating the self-assembly pathway is essentially important in the supramolecular synthesis of organic nano- and microarchitectures. Herein, we design a series of photoisomerizable chiral molecules, and realize precise control over pathway complexity with external light stimuli. The hidden single-handed microcoils, rather than the straight microribbons through spontaneous assembly, are obtained through a kinetically controlled pathway. The competition between molecular interactions in metastable photostationary intermediates gives rise to a variety of molecular packing and thereby the possibility of chirality transfer from molecules to supramolecular assemblies., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Despite many advances in the development of artificial systems with helical twist motions or deformations, obtaining materials that can undergo continuous twist movements upon an energy input remains a great challenge. In this work, a continuous twist movement of microribbons driven by scanning laser irradiation, a process that a twist generates initially at one end of the microribbon and is continuously transmitted to the other end and then kept twisting, is reported. Key factors to the achievement of this movement are the fabrication of elastic microribbons that possess relatively low elastic modulus and diagonal photoinduced π-stacking distortion relative to the microribbon long axis. Furthermore, the scanning laser irradiation is required to drive the π-stacking distortion with the spatiotemporal coordination for the continuous twist movement of microribbons. These findings may be extended to the achievement of other sophisticated continuous movements of microscale systems., (© 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Visible light has risen to become a very important facilitator for selective radical reactions enabled by well-cognized photocatalysts. The renaissance of visible-light photocatalysis on this matter partly relies on integrating it with other fields of catalysis. In parallel, 2,2,6,6-tetramethylpiperidin N-oxide (TEMPO), a quintessential persistent radical, has a wide range of uses owing to its exceptional redox behavior, which gives rise to its latest prominence in catalysis. Therefore, integrating the catalysis of TEMPO with photocatalysis to perform visible-light-induced selective reactions becomes a very convenient marriage of merits. In this context, the integration of different types of photocatalysts, including metal complexes, metal-free organic dyes, and semiconductors, with TEMPO for outstanding organic transformations will be summarized. To expand further the catalytic repertoire, the integration of TEMPOH analogues such as NHPI (N-hydroxyphthalimide) and NHS (N-hydroxysuccinimide) with photocatalysis will also be discussed. Hopefully, these advances will pave the way for more breakthroughs by integrating TEMPO and its analogues with photocatalysis to lead to a valuable blueprint for visible-light-induced selective organic transformations., (© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

A complex two-dimensional (2D) hierarchical heterostructure was fabricated by a sequential two-dimensional seeded self-assembly, which consisted of laterally grown nanotubes from one perylene monomer and terminally elongated nanocoils from a similar perylene monomer on microribbon seeds from a third perylene. Because the nanotube and nanocoil monomers can form kinetically trapped off-pathway aggregates to prevent self-nucleation and have similar molecular organizations to different facets of the seeds, the nanotube and nanocoil monomers preferentially nucleate and grow on the seed sides and terminal ends, respectively, to form a complex 2D hierarchical heterostructure. The strategy used in this work can be extended to fabricate other complex nanoarchitectures from small molecules., (© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

In aqueous TiO 2 photocatalytic hydroxylation of weakly polar aromatics, a series of inverse H/D KIEs of 0.7-0.8 were observed, which is different than the normal H/D kinetic isotope effects (KIEs) usually observed for polar aromatics. This result indicated that the oxidation started by photo-induced h vb + can be the rate-determining step., (© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

HO-adduct radicals have been investigated and confirmed as the common initial intermediates in TiO 2 photocatalysis and Fenton degradations of water-insoluble aromatics. However, the evolution of HO-adduct radicals to phenols has not been completely clarified. When 4-d-toluene and p-xylene were degraded by TiO 2 photocatalysis and Fenton reactions, respectively, a portion of the 4-deuterium or 4-CH 3 group (18-100 %) at the attacked ipso position shifted to the adjacent position of the ring in the formed phenols (NIH shift; NIH is short for the National Institutes of Health, to honor the place where this phenomenon was first discovered). The results, combined with the observation of a key dienyl cationic intermediate by in situ attenuated total reflectance FTIR spectroscopy, indicate that, for the evolution of HO-adduct radicals, a mixed mechanism of both the carbocation intermediate pathway and O 2 -capturing pathway occurs in both aqueous TiO 2 photocatalysis and aqueous Fenton reactions., (© 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

An air-stable copper-phenylacetylide nanobelt is synthesized and applied in organic pollutants elimination under visible light. Its versatile activity and reusability indicate it is a promising photocatalyst, arising from a band gap of 2.3 eV and the energetically favored electron transfer processes. The tunable structures and properties endow copper-based coordination polymers a prosperous prospect., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Novel direction-controlled movements of microribbons self-assembled from perylene diimide molecules are reported on various hydrophobic surfaces under scanning laser irradiation. A "dynamic exciton charge model" is developed to elucidate the underlying mechanism. The findings provide an innovative strategy for the design of microscale systems capable of continuous and directional movement driven by light., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Novel, chiral-selective linear nanotubular heterojunctions were achieved by living supramolecular polymerization of perylenediimide (PDI) derivatives. We demonstrate that the chiral seed can effectively bias achiral PDI molecules to polymerize on its ends in the identical helical sense. More interestingly, the chiral seed can bias the opposite enantiomers to grow expitaxially from its ends even in excess amounts relative to the seed. Furthermore, we demonstrate that the biasing effect of the chiral seed on the opposite enantiomer is not dependent on the length of the chiral seed but is related to the intrinsic length of the elongated nanotube from the opposite enantiomer. The fabrication of chiral-selective nanotubes was achieved by application of the unique biasing effect of the chiral seed in living supramolecular self-assembly., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Highly fluorescent bilayer-walled and monolayer-walled nanotubes are assembled from elaborately designed asymmetric perylene diimide (PDI) molecules. The diameter of bilayer-walled nanotubes increases with the size of the branched substituents at the meta-position of the phenyl moiety of PDI molecules, whereas that of monolayer-walled nanotubes remains unchanged regardless of the size of branched substituents., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

TiO2 photoredox catalysis has recently attracted much interest for use in performing challenging organic transformations under mild reaction conditions. However, the reaction scheme is hampered by the fact that TiO2 can only be excited by UV light of wavelengths λ shorter than 385 nm. One promising strategy to overcome this issue is to anchor an organic, preferably metal-free dye onto the surface of TiO2. Importantly, we observed that the introduction of a catalytic amount of the redox mediator TEMPO [(2,2,6,6-tetramethylpiperidin-1-yl)oxyl] ensured the stability of the anchored dye, alizarin red S, thereby resulting in the selective oxidation of organic sulfides with O2. This result affirms the essential role of the redox mediator in enabling the organic transformations by visible-light photoredox catalysis., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

In contrast to the widely used bottom-up strategy for preparing various complex nanostructures, the top-down strategy is rarely applied to generate complex nanostructures. This study reports the use of a unique combination of bottom-up and top-down processes for the time-resolved stepwise fabrication of novel photoconductive nanotubes from elaborately designed asymmetric perylene diimide molecules., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The hole-driving oxidation of titanium-coordinated water molecules on the surface of TiO2 is both thermodynamically and kinetically unfavorable. By avoiding the direct coordinative adsorption of water molecules to the surface Ti sites, the water can be activated to realize its oxidation. When TiO2 surface is covered by the H-bonding acceptor F, the first-layer water adsorption mode is switched from Ti coordination to a dual H-bonding adsorption on adjacent surface F sites. Detailed in situ IR spectroscopy and isotope-labeling studies reveal that the adsorbed water molecules by dual H-bonding can be oxidized to O2 even in the absence of any electron scavengers. Combined with theoretical calculations, it is proposed that the formation of the dual H-bonding structure can not only enable the hole transfer to the water molecules thermodynamically, but also facilitate kinetically the cleavage of O-H bonds by proton-coupled electron transfer process during water oxidation., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

An efficient redox reaction between organic substrates in solution and photoinduced h(+) vb /e(-) cb on the surface of photocatalysts requires the substrates or solvent to be adsorbed onto the surface, and is consequentially marked by a normal kinetic solvent isotope effect (KSIE ≥ 1). Reported herein is a universal inverse KSIE (0.6-0.8 at 298 K) for the reductive dehalogenation of aromatic halides which cannot adsorb onto TiO2 in a [D0 ]methanol/[D4 ]methanol solution. Combined with in situ ATR-FTIR spectroscopy investigations, a previously unknown pathway for the transformation of these aromatic halides in TiO2 photocatalysis was identified: a proton adduct intermediate, induced by released H(+) /D(+) from solvent oxidation, accompanies a change in hybridization from sp(2) to sp(3) at a carbon atom of the aromatic halides. The protonation event leads these aromatic halides to adsorb onto the TiO2 surface and an ET reaction to form dehalogenated products follows., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

A light-induced giant lateral or longitudinal morphological change in layered microribbons is reported. This morphological change originates from the directional sliding of the stacking layers with respect to one another between their polar surfaces, into which the photoexcited intermolecular non-bonded distortion is translated. Upon exposure to an electron beam, the laterally displaced layers slide back to their original positions., (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Core-shell TiO2 microspheres possess a unique structure and interesting properties, and therefore, they have received much attention. The high-energy facets of TiO2 also are being widely studied for the high photocatalytic activities they are associated with. However, the synthesis of the core-shell structure is difficult to achieve and requires multiple-steps and/or is expensive. Hydrofluoric acid (HF), which is highly corrosive, is usually used in the controlling high-energy facet production. Therefore, it is still a significant challenge to develop low-temperature, template-free, shape-controlled, and relative green self-assembly routes for the formation of core-shell-structured TiO2 microspheres with high-energy facets. Here, we report a template- and hydrofluoric acid free solvothermal self-assembly approach to synthesize core-shell TiO2 microspheres covered with high-energy {116}-facet-exposed nanosheets, an approach in which 1,4-butanediamine plays a key role in the formation of nanosheets with exposed {116} facets and the doping of nitrogen in situ. In the structure, nanoparticle aggregates and nanosheets with {116} high-energy facets exposed act as core and shell, respectively. The photocatalytic activity for degradation of 2,4,6-tribromophenol and Rhodamine B under visible irradiation and UV/Vis irradiation has been examined, and improved photocatalytic activity under visible light owing to the hierarchical core-shell structure, {116}-plane-oriented nanosheets, in situ N doping, and large surface areas has been found., (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Titanium dioxide with surface-loaded palladium (Pd-TiO2) was able to easily remove all ten bromine atoms from decabromodiphenyl ether (BDE209) within 1 h under the irradiation of sunlight or an artificial light source. By contrast, fewer than three bromine atoms were eliminated on the pristine TiO2 even with prolonged irradiation (5 h). During the photocatalytic debromination, moreover, the formed BDE intermediates exhibited a significant difference between the Pd-TiO2 and pristine TiO2 systems, and much less position selectivity for the debromination on Pd-TiO2 was observed than that on the pristine TiO2 surface. For another polybrominated diphenyl ether (BDE15), pristine TiO2 was incapable of its photocatalytic reduction, whereas the loading of Pd enabled its debromination to diphenyl ether within 20 min. In addition, an evident induction period appeared in the photocatalytic debromination of BDE15 on Pd-TiO2. The experiments imply that the Pd-cocatalyzed effect changes significantly the photocatalytic reductive debromination pathways., (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Epoxidation of olefins with H2O2 is one of the most important reactions in organic synthesis. We found that anatase TiO2 can be a good catalyst for the epoxidation of cyclooctene with H2O2 at room temperature. However, the catalyst deactivated quickly in the presence of excess amount of H2O2 because of the formation of inactive side-on Ti-η(2)-peroxide species on the surface of TiO2, the presence of which was confirmed by isotope-labelled resonance UV Raman spectroscopy and kinetics studies. Interestingly, the epoxidation reaction could be dramatically accelerated under irradiation of UV light with λ≥350 nm. This phenomenon is attributed to the photo-assisted removal of the inactive peroxide species, through which the active sites on the surface of anatase TiO2 are regenerated and the catalytic epoxidation of cyclooctene with H2O2 is resumed. This finding provides an alternative for sustained epoxidation reactions on TiO2 at room temperature. Moreover, it also has significant implications on the deactivation pathway and possible solutions in Ti-based heterogeneous catalysis or photocatalysis., (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The degradation behaviours of five straight-chain dicarboxylic acids (from ethanedioic acid to hexanedioic acid) were compared in aqueous TiO2-based photocatalysis. When all other conditions were identical, the degradation rates were found to fluctuate regularly with the parity of the number of carbon atoms. Dicarboxylic acids with an even number of carbon atoms (e-DAs) always degraded more slowly than those acids with an odd number of carbon atoms (o-DAs). This unusual fluctuation in the reactivity for the degradation of dicarboxylic acids by TiO2-based photocatalysis is very closely related to the different pre-coordination modes of the acids with the photocatalyst. Attenuated total reflection FTIR (ATR-FTIR) of e-DAs labelled with (13)C showed that both carboxyl groups of the acid coordinate to TiO2 through bidentate chelating forms. In contrast, only one carboxyl group of the o-DAs coordinated to TiO2 in a bidentate chelating manner, whereas the other formed a monodentate binding linkage. The bidentate chelating form with bilateral symmetric coordination did not favour degradation. Isotope-labelling experiments were performed with (18)O2 to observe the different ways in which incorporated oxygen entered the initial decarboxylated products of e- and o-DAs. For the degradation of butanedioic acid, (45.9±0.5) % of the oxygen in the formed propanedioic acid came from H2O, whereas for pentanedioic acid, (97.4±0.2) % of the oxygen in the formed butanedioic acid came from H2O. Our results demonstrate that in TiO2-based photocatalysis, the reactivity of active species, such as ·OH/h(vb)(+), is far from non-selective and that the attacks of these active species on organic substrates are significantly affected by the coordination patterns of the substrates on the TiO2 surface., (Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Let's facet it: TiO(2) mesocrystals (MCs; see figure) enclosed by (101) and (001) facets can be synthesized by a facile green approach and the ratio of (101)/(001) can be tuned simply by adjusting the solvothermal periods. The photocatalytic activity of TiO(2) MCs exposing high proportions of (101) facets possess higher photocatalytic activity than those with lower facets; this can be attributed to the synergistic effect of Ti(3+) and the (101)/(001) facet ratio., (Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Imines are important intermediates for the synthesis of fine chemicals, pharmaceuticals, and agricultural chemicals. Selective oxidation of amines into their corresponding imines with dioxygen is one of the most-fundamental chemical transformations. Herein, we report the oxidation of a series of benzylic amines into their corresponding imines with atmospheric dioxygen as the oxidant on a surface of anatase TiO(2) under visible-light irradiation (λ>420 nm). The visible-light response of this system was caused by the formation of a surface complex through the adsorption of a benzylic amine onto the surface of TiO(2). From the analysis of products of specially designed benzylic amines, we demonstrated that a highly selective oxygenation reaction proceeds via an oxygen-transfer mechanism to afford the corresponding carbonyl compound, whose further condensation with an amine would generate the final imine product. We found that when primary benzylic amines (13 examples), were chosen as the substrates, moderate to excellent selectivities for the imine products were achieved (ca. 38-94%) in moderate to excellent conversion rates (ca. 44-95%). When secondary benzylic amines (15 examples) were chosen as the substrates, both the corresponding imines and aldehydes were detected as the main products with moderate to high conversion rates (ca. 18-100%) and lower selectivities for the imine products (ca. 14-69%). When tribenzylamine was chosen as the substrate, imine (27%), dibenzylamine (24%), and benzaldehyde products (39%) were obtained in a conversion of 50%. This report can be viewed as a prototypical system for the activation of C-H bonds adjacent to heteroatoms such as N, O, and S atoms, and oxofuctionalization with air or dioxygen as the terminal oxidant under visible-light irradiation using TiO(2) as the photocatalyst., (Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The hydroxylation process is the primary, and even the rate-determining step of the photocatalytic degradation of aromatic compounds. To make clear the hydroxylation pathway of aromatics, the TiO(2) photocatalytic hydroxylation of several model substrates, such as benzoic acid, benzene, nitrobenzene, and benzonitrile, has been studied by an oxygen-isotope-labeling method, which can definitively assign the origin of the O atoms (from oxidant O(2) or solvent H(2)O) in the hydroxyl groups of the hydroxylated products. It is found that the oxygen source of the hydroxylated products depends markedly on the reaction conditions. The percentage of the products with O(2)-derived hydroxyl O atoms increases with the irradiation time, while it decreases with the increase of substrate concentration. More intriguingly, when photogenerated valence-band holes (h(vb)(+)) are removed, nearly all the O atoms (>97 %) in the hydroxyl groups of the hydroxylated products of benzoic acid come from O(2), whereas the scavenging of conduction-band electrons (e(cb)(-)) makes almost all the hydroxyl O atoms (>95 %) originate from solvent H(2)O. In the photocatalytic oxidation system with benzoic acid and benzene coexisting in the same dispersion, the percentage of O(2)-derived hydroxyl O atoms in the hydroxylated products of strongly adsorbed benzoic acid (ca. 30 %) is much less than in that of weakly adsorbed benzene (phenol) (>60 %). Such dependences provide unique clues to uncover the photocatalytic hydroxylation pathway. Our experiments show that the main O(2)-incorporation pathway involves the reduction of O(2) by e(cb)(-) and the subsequent formation of free (⋅)OH via H(2)O(2), which was usually overlooked in the past photocatalytic studies. Moreover, in the hydroxylation initiated by h(vb)(+), unlike the conventional mechanism, the O atom in O(2) cannot incorporate into the product through the direct coupling between molecular O(2) and the substrate-based radicals., (Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The aerobic decarboxylation of saturated carboxylic acids (from C(2) to C(5)) in water by TiO(2) photocatalysis was systematically investigated in this work. It was found that the split of C(1)-C(2) bond of the acids to release CO(2) proceeds sequentially (that is, a C(5) acid sequentially forms C(4) products, then C(3) and so forth). As a model reaction, the decarboxylation of propionic acid to produce acetic acid was tracked by using isotopic-labeled H(2)(18)O. As much as ≈42% of oxygen atoms of the produced acetic acids were from dioxygen ((16)O(2)). Through diffuse reflectance FTIR measurements (DRIFTS), we confirmed that an intermediate pyruvic acid was generated prior to the cut-off of the initial carboxyl group; this intermediate was evidenced by the appearance of an absorption peak at 1772 cm(-1) (attributed to C=O stretch of α-keto group of pyruvic acid) and the shift of this peak to 1726 cm(-1) when H(2)(16)O was replaced by H(2)(18)O. Consequently, pyruvic acid was chosen as another model molecule to observe how its decarboxylation occurs in H(2)(16)O under an atmosphere of (18)O(2). With the α-keto oxygen of pyruvic acid preserved in the carboxyl group of acetic acid, ≈24% new oxygen atoms of the produced acetic acid were from molecular oxygen at near 100% conversion of pyruvic acid. The other ≈76% oxygen atoms were provided by H(2)O through hole/OH radical oxidation. In the presence of conduction band electrons, O(2) can independently accomplish such C(1)-C(2) bond cleavage of pyruvic acid to generate acetic acid with ≈100% selectivity, as confirmed by an electrochemical experiment carried out in the dark. More importantly, the ratio of O(2) participation in decarboxylation increased along with the increase of pyruvic acid conversion, indicating the differences between non-substituted acids and α-keto acids. This also suggests that the O(2)-dependent decarboxylation competes with hole/OH-radical-promoted decarboxylation and depends on TiO(2) surface defects at which Ti(4c) sites are available for the simultaneous coordination of substrates and O(2).