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The as-prepared NiTAPP-NiACQ exhibits excellent long-term durability and remarkable HER performance with a low overpotential of 117 mV at 10 mA cm−2, which is quite comparable to many reported electrocatalytic HER systems. [Display omitted] To realize efficient water splitting, a highly promising hydrogen evolution reaction (HER) electrocatalyst is needed for the generation of hydrogen. Herein, we demonstrate a novel acenaphthenediimine complex-bridged porphyrin porous organic polymer (NiTAPP-NiACQ) with enriched active metal sites and hierarchical pores. The as-prepared NiTAPP-NiACQ exhibits good long-term durability and remarkable HER performance in 1.0 M KOH with a low overpotential of 117 mV at 10 mA cm−2, which is comparable to many previously reported electrocatalytic HER systems. Furthermore, a simple water-alkali electrolyzer using NiTAPP-NiACQ as the cathode requires a small cell voltage of 1.59 V to deliver a current density of 10 mA cm−2 at room temperature, along with outstanding durability. NiTAPP-NiACQ features not only a metal ion as the catalytic active center in the porphyrin core but also metal ion coordination on the anthraquinone component to promote HER performance, enabling multiple metal ions as the electrocatalytic active sites for the HER reaction. The excellent HER activity of NiTAPP-NiACQ is ascribed to a combination of mechanisms. These findings highlight the viability of porphyrin-derived porous organic polymers in energy conversion processes. [ABSTRACT FROM AUTHOR]

A novel nitrogen-rich azo-bridged metallated porphyrin POP (CoTAPP-CoTNPP) network was engineered by the combination of cobalt porphyrins with azo groups together, which exhibits an enhanced HER performance as compared to other control samples. [Display omitted] The potential of porous organic polymers (POPs) toward electrocatalytic water splitting have attracted considerable scientific attention, due to their high specific surface areas, superlative porosity and diverse electronic structures; yet it remains challenging. Herein, we report a facile synthesized novel nitrogen-rich azo-bridged metallated porphyrin POP (CoTAPP-CoTNPP) for improving the hydrogen evolution reaction (HER) activity. The incorporation of the cobalt porphyrins and the azo groups endows CoTAPP-CoTNPP with effective charge transfer efficiency and large π-conjugated porous frameworks, thus enhancing the HER performance. Origins of the excellent HER performance of the material are evaluated using a series of structural and electrochemical measurements. Remarkably, CoTAPP-CoTNPP exhibits low overpotentials of 103 and 170 mV to reach 10 mA cm−2 in acidic and alkaline media, respectively, outperforming many previously reported HER electrocatalysts. These results demonstrate the enormous potential of the as-prepared azo-linked porphyrin POP for electrocatalytic water splitting. [ABSTRACT FROM AUTHOR]

Integrating various active sites into a multi-component system might significantly enhance the oxygen evolution reaction (OER) performance. Herein, the as-prepared iron-molybdenum nitride/molybdenum oxide (Fe-Mo5N6/MoO3-550) composite electrocatalyst under optimum conditions demonstrates excellent electrocatalytic performance toward OER and reaches current densities of 10 and 20 mA cm−2 at overpotentials of 201 and 216 mV, respectively. The OER performance of Fe-Mo5N6/MoO3-550 exceeds that of most previously reported electrocatalytic systems. The significant improvement in the OER performance is ascribed to a combination of mechanisms. The strong electronic interactions among the Fe, Mo5N6 and MoO3 species can accelerate the OER reaction kinetics, which contributes to the OER performance. This work provides new insights into the construction of efficient electrocatalytic materials with inexpensive metals. [ABSTRACT FROM AUTHOR]

Sluggish oxygen evolution reaction (OER) is considered to be the bottleneck that restricts the usage of electrocatalytic water splitting to generate hydrogen. With this in mind, we demonstrate the design and preparation of a series of Mo 15 S 19 /Ni:FeOOH heterostructures toward water oxidation. As expected, the considerable acceleration of OER process is achieved by the combination of Mo 15 S 19 with Ni:FeOOH, due to the formation of heterojunction. Under the optimized conditions, the as-prepared Mo 15 S 19 /Ni:FeOOH-21 exhibits a lower overpotential (214 mV vs RHE at 10 mA cm−2) than other control samples. The OER activity of Mo 15 S 19 /Ni:FeOOH-21 is found to be comparable to and/or better than the state-of-the-art OER electrocatalysts reported in the literature recently, making it a promising OER electrocatalyst in the industrial water electrolysis. This work opens up an efficient avenue to rational design of other high-performance composite OER electrocatalysts. [ABSTRACT FROM AUTHOR]

Though bismuth vanadate (BiVO 4) exhibits a promising potential as a semiconductor photoanode toward photoelectrochemical (PEC) water oxidation, its PEC performance is still limited by the poor charge carrier transport and sluggish oxygen evolution kinetics. Herein, the polyaniline (PANI) and cobalt coordinated-phthalocyanines (CoTcPc) were introduced onto the BiVO 4 semiconductor substrate, constructing the integrated CoTcPc/nPANI/BiVO 4 (n = 30, 60 and 90, n represents the deposition time for PANI with the unit of s) composite photoanodes. It is demonstrated that the PEC water oxidation activity of BiVO 4 is significantly boosted by the incorporation of PANI and CoTcPc, stemming from the improved electron/hole transfer, enhanced charge separation efficiency, and accelerated carrier mobility and water oxidation kinetics. CoTcPc/60PANI/BiVO 4 composite photoanode with the optimized compositions exhibits an enhanced photocurrent density of 4.03 mA/cm2 at 1.23 V vs. RHE under illumination, ranking among the best records reported recently. Furthermore, the roles of electrodeposition time to generate PANI are also distinguished through experimental studies. These results reveal the crucial role of engineering the hole transfer layer to optimize the semiconductor photoanodes toward efficient PEC water oxidation. • The water oxidation activity of BiVO 4 is significantly improved. • The synergistic effect significantly contribute to PEC water oxidation activity. • An obviously improved Faradaic efficiency for water oxidation was also achieved. • Engineering the hole transfer layer is an effective method to optimize OER process. [ABSTRACT FROM AUTHOR]

Herein, we demonstrate a facile strategy for constructing an efficient and stable hydrogen evolution reaction (HER) catalyst, i.e. a tin porphyrin axially-coordinated 2D covalent organic polymer (SnTPPCOP). SnTPPCOP exhibits promising HER activity with a low overpotential of 147 mV at 10 mA cm−2 due to its unique structural properties, ranking among the best records reported recently. [ABSTRACT FROM AUTHOR]

Herein, a series of FeOx-MoP@MWCNT composite electrocatalysts was designed and prepared to investigate the influence of the content of FeOx on the water splitting performance. The optimized FeOx-MoP@MWCNTs-2 exhibits excellent hydrogen and oxygen evolution reaction activity while a cell voltage of 1.51 V with outstanding stability is attained, attributed to the synergistic effect of each component, as evidenced by the experimental and density functional theory results. The observed electrocatalytic activity outperforms current state-of-the-art non-precious metal electrocatalysts. [ABSTRACT FROM AUTHOR]

Herein, we report a novel graphene oxide (GO) nanohybrid covalently functionalized by covalent organic polymer (COP) based on porphyrin (GO-TPPCOP), as the optical limiter and hydrogen evolution reaction (HER) electrocatalyst. The GO-TPPCOP nanohybrid exhibits markedly enhanced optical limiting and HER activity over that of TPP, GO and TPPCOP alone. More importantly, the optical limiting property and HER activity of GO-TPPCOP nanohybrid are comparable to the state-of-the-art activity of materials from some previous reports. The possible mechanisms of optical limiting and HER are explored by various means, including UV-Vis absorption, fluorescence, photocurrent, electrochemical impedance spectra and Raman spectroscopic techniques. It is demonstrated that the synergistic effect and charge transfer between GO and TPPCOP are important factors in determining its optical limiting and HER performances. These results demonstrate a new strategy to design and develop functional nanohybrids for efficient optical limiting and HER activity by the covalent linkage of GO with COPs. [ABSTRACT FROM AUTHOR]

Herein, we demonstrate the first example of a novel electrocatalytic hybrid system (CoTPP–PZSNT) with a push–pull motif to boost hydrogen evolution reaction (HER) activity. CoTPP–PZSNT exhibits an efficient HER activity, with overpotentials of 157 and 109 mV at 10 mA cm−2 in 1.0 M KOH and 0.5 M H2SO4 solutions, respectively. The HER performance of CoTPP–PZSNT outperforms many previously reported HER catalysts, due to efficient charge transfer between each component. [ABSTRACT FROM AUTHOR]

Integration of metalloporphyrin moieties into the porous organic polymer (POP) framework via conjugated linkages can contribute to the hydrogen evolution reaction (HER) performance, due to the interpenetrated macrocyclic hollow channels, and the well-defined catalytic sites. Herein, a porous cobalt porphyrinic network (CoTPP-POP) with benzene linkages was designed and prepared for water reduction. CoTPP-POP exhibits the excellent HER performance with a low overpotential (150 mV at 10 mA cm−2), good long-term durability and remarkable Faradaic efficiency in acidic medium. The HER performance of CoTPP-POP is comparable to many previously reported non-noble electrocatalysts. This contribution demonstrates a facile approach to design other advanced systems for energy-related electrocatalysis. • A porous cobalt porphyrinic network (CoTPP-POP) with benzene linkages was designed. • CoTPP-POP exhibits relative low overpotential of 150 mV to reach 10 mA cm−2. • The effective HER activity is ascribed to a combination of mechanisms. [ABSTRACT FROM AUTHOR]

Covalent organic polymers have attracted much attention due to their high specific surface area, superlative porosity, and diversity in electronic structure. Herein, a novel porous cobalt-porphyrin-based covalent organic polymer (CoCOP) is fabricated through the Schiff-base condensation reaction, which is used as a difunctional electrocatalyst for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). The CoCOP possesses a high surface area and strong synergistic effect between the cobalt-porphyrins and the C N groups, resulting in efficient HER and OER performances. The CoCOP required relatively low overpotentials for both HER (121 mV to reach 1.0 mA cm−2 and 310 mV to reach 10 mA cm−2) and OER (166 mV to reach 1.0 mA cm−2 and 350 mV to reach 10 mA cm−2) in alkaline media. This work may provide a new idea for the design of non-noble metal-based coordination polymers with excellent structure and high electrocatalytic performance. [ABSTRACT FROM AUTHOR]

Graphene oxide (GO) ternary nanohybrids functionalized by axially coordinated gallium porphyrins have been prepared, and characterized by various spectroscopic techniques. The Z-scan experimental results show that the GaTPP-GO-GaTTP ternary nanohybrid possesses enhanced nonlinear optical properties in comparison with GO, gallium porphyrins and two other binary nanohybrids (GaTPP-GO and GaTTP-GO) under 4 ns laser pulses, which is ascribed to a combination of mechanisms. The different types of porphyrins as a major factor have a significant effect on the photophysical and nonlinear optical (including optical limiting) performances of the as-prepared nanohybrids. By adjusting the types of porphyrins grafted onto GO, the optical nonlinearity can be precisely tuned. The role of considerable electronic interactions and charge transfer in the nonlinear optical performance of GaTPP-GO-GaTTP was clarified by using the UV/vis absorption, fluorescence, Raman, transient photocurrent and electrochemical impedance spectroscopy techniques. [ABSTRACT FROM AUTHOR]

In this contribution, two constituent-tunable metallophthalocyanine covalent organic polymers (MPc-COPs) covalently attached to graphene oxide (GO-PcP 1 and GO-PcP 2) were rationally designed and fabricated for optoelectronics and electrocatalysis. The resultant GO-PcP nanohybrids exhibit markedly enhanced nonlinear optical and optical limiting performances over those of their components and physical mixtures at 532 nm in the nanosecond pulse range. The optical nonlinearity can be further optimized by tuning the linkage type between the four-branched tetraamine metallophthalocyanine units. The hydrogen evolution reaction (HER) is investigated by linear sweep voltammetry in a 0.5-M H 2 SO 4 aqueous solution. Under optimal conditions, the overpotentials needed to reach 1 mA cm−2 are measured as 237 and 210 mV for GO-PcP 1 and GO-PcP 2, respectively, which places GO-PcP 2 as the best metallophthalocyanine polymer-based HER catalyst to be reported in the literature. The improved performances were ascribed to the positive synergistic effects between MPc-COPs and GO. Notably, the present study introduces a new strategy for the precise preparation of MPc-COP-based nanomaterials while exploring their applications to develop highly efficient optical limiters and electrocatalysts. [ABSTRACT FROM AUTHOR]

Herein, three polypyrrole-based nanohybrids were designed and prepared via a nucleophilic substitution reaction, i.e., peripherally substituted porphyrin-functionalized PPy (TPP-PPy), axially coordinated metal-porphyrin-functionalized PPy (SnTPP-PPy), and polypyrrole ternary nanohybrids co-functionalized with peripherally substituted porphyrins and axially coordinated metal-porphyrins (TPP-PPy-SnTPP). The TPP-PPy, SnTPP-PPy and TPP-PPy-SnTPP nanohybrids exhibited improved nonlinear optical and optical limiting performances when compared to the individual PPy and porphyrins under 4 ns, 532 nm laser pulses. Their improved optical nonlinearities were ascribed to a combination of mechanisms and efficient charge transfer effect between the porphyrins and PPy. The charge transfer effect between the porphyrins and PPy was confirmed by UV-vis absorption, fluorescence and electrochemical impedance spectroscopy. The TPP-PPy-SnTPP ternary nanohybrid exhibited the best nonlinear absorption, nonlinear refraction and optical limiting performances because of more effective charge transfer effect, which provides a new avenue for the development of polypyrrole–porphyrin systems in the fields of nonlinear optics and optoelectronic devices. [ABSTRACT FROM AUTHOR]

An organic-inorganic nanohybrid material (TPPOH-GO) is produced by linking monohydroxyporphyrin (TPPOH) and graphene oxide (GO) together via the ester bond, and the formation of this nanohybrid has been affirmed by various spectroscopy techniques. Nonlinear optical (NLO) and optical limiting (OL) performances were studied by the Z-scan technique. Because of the efficient electric charge transfer efficiency between TPPOH and GO, the as-prepared TPPOH-GO nanohybrid exhibits superior NLO and OL performances compared to those of TPPOH and GO. The photophysical, NLO and OL performances of hydrothermally reduced materials (TPPOH-RGO 1, TPPOH-RGO 2, TPPOH-RGO 3) are tuned by controlling the hydrothermal temperatures, implying the scope of using them as optical limiters. • The hybrid material that the porphyrin is covalently linked to GO is reduced for the first time. • Significantly enhanced optical nonlinearity was observed for the material being reduced. • The enhanced performance is ascribed to efficient charge transfer. [ABSTRACT FROM AUTHOR]

Abstract Nonlinear optical nanostructured materials are gaining increased interest as optical limiters for various applications. In the present case, two soluble porphyrins (TPP) covalently functionalized hexagonal boron nitride (h-BN) nanohybrids (BN-TPP 1 and BN-TPP 2) as optical limiter were prepared for the first time, and characterized by various spectroscopic techniques. The covalent attachment of porphyrins onto the surfaces of h-BN improves the ease of processing of these BN-porphyrins composite materials. The results of Z-scan measurements at 532 nm in the nanosecond laser pulse regime indicated that the BN-TPP nanohybrids exhibited markedly improved nonlinear absorption and optical limiting performances compared to a control sample consisting of a covalently unattached physical blend of h-BN and porphyrins, and the porphyrin covalently functionalized graphene nanohybrids, as well as to either h-BN or TPP alone. The enhanced optical nonlinearities can be ascribed to the synergetic effects originating from charge transfer between the two counterparts. The effects of porphyrins on the structure, thermal, linear and nonlinear optical responses of the h-BN were investigated in detail. The efficient nonlinear optical performances make the as-prepared nanohybrids excellent candidates for optical limiting applications. Highlights • Porphyrins covalently functionalized boron nitride is prepared for the first time. • The solubility of boron nitride is improved by the introduction of porphyrins. • Significantly enhanced optical nonlinearity is observed for the obtained hybrids. • The improved performance is ascribed to the synergetic effects. [ABSTRACT FROM AUTHOR]

Abstract To improve the dispersibility of single walled carbon nanotube (SWCNT) in common organic solvents and adjust its photoelectronic performance, two methacrylate-co-porphyrins covalently functionalized SWCNT nanohybrids (SWCNT-TPP 1 and SWCNT-TPP 2) were prepared by radical polymerization. This attachment of porphyrins onto the surface of SWCNT significantly improves their solubility and dispersion stability of the SWCNT-based materials in organic solvents. The electronic interactions between porphyrins and SWCNT were investigated by the UV–vis, fluorescence and Raman spectroscopic methods. Z-scan measurements suggested that both nanohybrids exhibited increased nonlinear absorption and optical limiting performances compared to the separate SWCNT and porphyrins, which can be ascribed to the synergetic effects originating from the charge transfer effect between the two counterparts. The best optical limiting performance is observed for SWCNT-TPP 1 due to more effective charge transfer effect in comparison with those of other samples. These results suggest that the radical polymerization is a useful approach towards the rational design of solution-processible yet stable optical limiting materials, and this concept may be readily extended to other directional optoelectronic properties. Highlights • Two methacrylate-co-porphyrins covalently functionalized SWCNT were prepared. • The solubility and dispersion stability of the SWCNT were improved. • The enhanced optical limiting was observed due to the efficient charge transfer. [ABSTRACT FROM AUTHOR]

Abstract The polyaniline (PANI) covalently grafted reduced graphene oxide (RGO) nanohybrids (RGO-PANI 1, RGO-PANI 2 and RGO-PANI 3) were fabricated by the in situ synthesis of PANI on the surface of p -phenylenediamine (PPD) functionalized graphene oxide (GO). The formation of RGO-PANI nanohybrids was confirmed by various spectroscopic techniques. The nonlinear optical performances of the as-prepared samples were investigated by the Z-scan measurements at 532 and 1064 nm with 4 ns laser pulses, the results displaying that the chemical nanohybrids (RGO-PANI 1, RGO-PANI 2 and RGO-PANI 3) exhibited enhanced optical nonlinearities compared to those of the benchmark material C 60 , and the constituent RGO and PANI, due to the synergistic effects stemming from charge transfer between the two components. The role of charge transfer in the optical nonlinearity was clarified with the help of photocurrent and electrochemical impedance spectroscopies. By controlling the concentration of original reactants in the precursor, the PANI content in RGO-PANI nanohybrids can be precisely adjusted so that the optical nonlinearity can be tuned. Graphical abstract Due to the efficient charge transfer effect, significant improvement in optical nonlinearities is achieved by covalent grafting of polyaniline onto the surface of reduced graphene oxide. Image 1 Highlights • Three reduced graphene oxide-polyaniline nanohybrids were prepared. • The nanohybrids exhibit efficient optical nonlinearities. • The optical nonlinearity can be tuned by adjusting the original reactant content. • The improved nonlinearity is ascribed to the efficient charge transfer effect. [ABSTRACT FROM AUTHOR]

A facile route to assemble pyridine anchored methine-bridged polypyrrole to metal-porphyrins through axial bonding has been demonstrated, and the as-prepared nanocomposites exhibit very distinctive broadband nonlinear optical performances compared to their precursors at both 532 and 1064 nm, due to an accumulation effect. [ABSTRACT FROM AUTHOR]

Considerable attention has been paid to design multifunctional hybrid materials for developing novel optoelectronic systems. Here, a series of novel porphyrin decorated Bi 2 O 2 CO 3 nanocomposites (BOC/TPP) loaded with different porphyrin contents was prepared by a facile solvothermal technique to maximize the photocatalysis and optical nonlinearity. The photoresponsive range of the BOC/TPP nanocomposites can be extended from UV to visible light, and the band gap can be continuously tuned. The wide absorption of the as-prepared nanocomposites in the visible light region makes them suitable for photocatalytic and nonlinear transmission studies. The associated photocatalysis and optical nonlinearity for the BOC/TPP nanocomposites are shown to be dependent on the contents of porphyrin. Compared to BOC, TPP and other prepared nanocomposites with different TPP loadings, the BOC/0.03TPP nanocomposite with 3 wt% TPP exhibits the highest photocatalytic performance and nonlinear optical absorption effect, due to the efficient interfacial charge transfer and the strong interfacial electronic interactions between TPP and BOC. These findings provide an ideal scientific platform to guide the rational design of difunctional nanomaterials with desired optoelectronic performances. [ABSTRACT FROM AUTHOR]

A series of novel metal-porphyrins (MTPPs, M(II) = Co, Ni, Cu) hybridized graphite-like carbon nitride (g-C 3 N 4 ) has been successfully synthesized by a facile solvothermal method. The microstructure and chemical structure of the MTPP/g-C 3 N 4 nanocomposites were characterized by Fourier transform infrared spectroscopy, field emission scanning electron microscopy, and X-ray photoelectron spectroscopy. The MTPP/g-C 3 N 4 nanocomposites exhibited enhanced photocatalytic performances for the photodegradation of rhodamine B in comparision with those of g-C 3 N 4 and the MTPPs precursors. The excellent photocatalytic performance was observed for CoTPP/g-C 3 N 4 compared to those of g-C 3 N 4 , NiTPP/g-C 3 N 4 and CuTPP/g-C 3 N 4 . The rational mechanisms responsible for deteriorating pollutants were proposed, which could be mainly ascribed to the more effective interfacial charge transfer and the interfacial electronic interactions between CoTPP and g-C 3 N 4 . The UV-visible diffused reflectance spectroscopy, photoluminescence, photocurrent spectroscopy and electrochemical impedance spectroscopy studies confirmed that the charge separation efficiency was greatly improved by coupling g-C 3 N 4 with MTPPs. [ABSTRACT FROM AUTHOR]

The electrochemical water splitting in strongly acidic medium with noble-metal-free electrocatalysts remains a desirable yet technological challenge. Herein, we developed a series of porphyrin coordination polymer supported transition-metal sulfides as bifunctional electrocatalysts (Co 3 S 4 @MoS 2 @nTiPCP, n = 10, 20 or 30) that performs well in acidic media. The optimal Co 3 S 4 @MoS 2 @20TiPCP achieves current densities of 10 mA cm−2 at overpotentials of 247 and 110 mV for acidic OER and HER, respectively. Particularly, an electrolyzer with better long-term stability using Co 3 S 4 @MoS 2 @20TiPCP as both cathode and anode exhibits a low cell voltage of 1.41 V at 10 mA cm−2 in acid, outperforming most other reported electrocatalysts elsewhere. The efficient electrochemical water splitting is ascribed to the synergetic effect and the unique structure characteristics. DFT calculations demonstrate that the Co atoms in Co 3 S 4 @MoS 2 @20TiPCP are the major active sites for electrochemical water splitting thanks to regulated electronic structures and reduced reaction energy barrier. Porphyrin coordination polymer supported transition-metal sulfides exhibit effective overall water splitting in acidic media, due to the synergetic effect between each component and the unique structure characteristics. [Display omitted] • Porphyrin coordination polymer supported metal sulfides as were prepared. • The samples show efficient acidic water electrooxidation. • The efficient acidic electrochemical water splitting is also observed. [ABSTRACT FROM AUTHOR]

Polypyrrole (PPy) and its acid/base composites (PPy·H 2 SO 4 , PPy·HCl and PPy·NH 3 ·H 2 O) were successfully synthesized and were characterized respectively by using fourier transform infrared, ultraviolet/visible absorption, X-ray diffraction, transmission electron microscopy and Raman spectroscopic techniques. The nonlinear optical properties of PPy and its acid/base composites were investigated using nanosecond Z-scan measurements at 532 nm. At the identical linear transmittance, the saturable absorption of pure PPy was changed to reverse saturable absorption by doping with acid (HCl and H 2 SO 4 ) and base (NH 3 ·H 2 O). The possible mechanisms for the different nonlinear properties were also discussed. [ABSTRACT FROM AUTHOR]

TiO 2 /reduced graphene oxide (RGO) nanocomposites G x (RGO titania nanocomposite, x grams tetrabutyl titanate per 0.03 g RGO, x = 0.25, 0.50, 1.00) were prepared by a hydrothermal method: graphene oxide was reduced to RGO in a 2:1 water:ethanol mixture in the presence of varying quantities of tetrabutyl titanate, which deposited as TiO 2 on the RGO sheets. The nanocomposites were characterized by a combination of Fourier transform infrared spectroscopy, diffuse reflectance ultraviolet–visible spectroscopy, photoluminescence spectroscopy, Raman spectroscopy, X-ray powder diffraction, X-ray photoelectron spectroscopy and transmission electron microscopy studies. The nanocomposite G0.25 exhibits enhanced nonlinear optical properties compared to its individual components, which is ascribed to a combination of mechanisms. The role of defects and electron/energy transfer in the optical limiting performance of G0.25 was clarified with the help of Raman and photoluminescence spectroscopies. Intensity-dependent switching between reverse saturable absorption and saturable absorption behavior was observed with the G0.50 nanocomposite. [ABSTRACT FROM AUTHOR]

A novel zinc porphyrin (ZnTPP) derivative bearing an E -stilbazole chromophore in the axial position (ZnTPPL) was designed and prepared. Z-scan studies reveal that this complex exhibits improved nonlinear optical absorption and refraction in comparison with ZnTPP. In addition, the molecular structure of the complex was determined by X-ray diffraction study. [ABSTRACT FROM AUTHOR]

Allyloxyporphyrin-functionalized multiwalled carbon nanotubes (MWCNT-TPP) were synthesized by radical polymerization and characterized by FTIR, UV/Vis absorption, and X-ray photoelectron spectroscopy; elemental analysis; TEM; and thermogravimetric analysis. Z-scan studies revealed that this nanohybrid exhibits enhanced nonlinear optical (NLO) properties compared to a control sample consisting of a covalently unattached physical blend of MWCNTs and porphyrin, as well as to the separate MWCNTs and porphyrin. At the wavelengths used, the mechanism of enhanced optical limiting likely involves reverse saturable absorption, nonlinear scattering, and photoinduced electron/energy transfer between the MWCNTs and the porphyrin. The role of electron/energy transfer in the NLO performance of MWCNT-TPP was investigated by Raman and fluorescence spectroscopy. [ABSTRACT FROM AUTHOR]

Two multi-walled carbon nanotube (MWCNT)-based nanohybrids, MWCNT-ZnTPP and MWCNT-TPP (TPP=5-[4-{2-(4-formylphenoxy)- ethyloxy}phenyl]-10,15,20-triphenylporphyrin, ZnTPP=5-[4-{(4-formylphenyl)ethynyl}phenyl]-10,15,20-triphenylporphinatozinc(II)), were prepared directly from pristine MWCNTs through 1,3-dipolar cycloaddition reactions. Covalent attachment of the porphyrins to the surfaces of the MWCNTs was confirmed by Fourier transform infrared spectroscopy, ultraviolet/visible absorption, fluorescence, Raman, and X-ray photoelectron spectroscopy, elemental analysis, transmission electron microscopy, and thermogravimetric analysis. Attachment of the porphyrin moieties to the surface of the MWCNTs significantly improves the solubility and ease of processing of these MWCNT-porphyrin composite materials. Z-scan studies reveal that these MWCNT-porphyrin nanohybrids exhibit enhanced nonlinear optical properties under both nanosecond and picosecond laser pulses at λ=532 nm in comparison with free MWCNTs and the free porphyrin chromophores, whereas superior optical limiting performance was displayed by MWCNT-porphyrin composite materials rather than MWCNTs/ZnTPP and MWCNTs/TPP blends, which is consistent with a remarkable accumulation effect as a result of the covalent linkage between the porphyrin and the MWCNTs. [ABSTRACT FROM AUTHOR]

Abstract: Two graphene oxide (GO)-based nanohybrid materials possessing covalent linkages to axially-coordinated tetraphenylporphyrin (TPP), GO–TPP, were prepared and were characterized by Fourier transform infrared (FT-IR), Ultraviolet–visible (UV–Vis) absorption, steady state fluorescence, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), thermogravimetric analysis (TGA), elemental analysis and Raman spectroscopic techniques. The nonlinear optical properties and optical limiting performance of GO, GO–TPP nanohybrids and the free porphyrins dihydroxotin(IV) tetraphenylporphyrin (SnTPP) and the phosphorus-cored porphyrin (PTPP) were investigated using nanosecond and picosecond Z-scan measurements at 532nm. At the identical mass concentration of 0.2mgmL−1, GO–TPP nanohybrids exhibited enhanced nonlinear optical properties and optical limiting performance, ascribed to a combination of nonlinear scattering and/or two-photon absorption with reverse saturable absorption, and the photo-induced electron or energy transfer from the electron-donor porphyrin moiety to the acceptor graphene. [Copyright &y& Elsevier]

Three novel semiconductor composite photoanodes (BiVO 4 /GO/CoTPP(OH) n , n = 1, 4 and 8) are designed and prepared by decorating BiVO 4 with graphene oxide (GO) and cobalt porphyrins bearing different number of hydroxyl groups. The introduction of GO and CoTPP(OH) n onto the BiVO 4 surface has been confirmed by transmission electron microscopy, scanning electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction, Fourier transform infrared and Raman spectroscopic techniques, endowing BiVO 4 with improved charge transfer and broadened light absorption ability. Their viability as photoelectrochemical system is investigated under AM 1.5 G light irradiation, the photoelectrochemical water splitting performance being found to be dependent on the type of cobalt porphyrins. The BiVO 4 /GO/CoTPP(OH) 4 is found to exhibit the largest photocurrent density of 5.27 mA/cm−2 at 1.23 V vs. RHE due to a combination of mechanisms. • Porphyrin and GO decorated BiVO4 photoanodes have been successfully developed. • The introduction of porphyrin and GO can improve the charge transfer efficiency. • The type of porphyrins has a significant influence on the PEC water splitting. • The obtained photoanodes exhibit efficient performance in PEC water splitting. [ABSTRACT FROM AUTHOR]

Herein, a series of g-C3N4 supported bimetallic sulfide nanostructures (Ni3S2/MoS2/ng-C3N4, n = 10, 20 and 30) was prepared by a hydrothermal method and subsequently a thermal annealing approach. Ni3S2/MoS2/20g-C3N4 with controlled composition exhibits efficient OER activity with a low overpotential of 183 mV at 10 mA cm−2, which outperforms the vast majority of sulfide OER electrocatalysts reported previously. [ABSTRACT FROM AUTHOR]

In this contribution, we disclose that reaction of the tetrakis(4-aminophenyl)porphyrin (TPP) and tetraaminophthalocyanine (ZnPc) with GO gives a donor-acceptor type hybrid material (TPP-GO-ZnPc). An analysis of the structure-property relationships in redox and optoelectronic performances has been performed by comparing their photophysical spectroscopy and electrochemistry. The results reveal that the resultant TPP-GO-ZnPc ternary nanohybrid exhibits enhanced optical limiting and HER response in comparison with those of TPP-functionalized GO (TPP-GO), ZnPc-functionalized GO (ZnPc-GO) and their constituents, stemming from a combination of mechanisms and more effective charge transfer effect. The strong electronic interactions and charge transfer effect within TPP-GO-ZnPc has been investigated by the UV–Vis absorption, photocurrent response, fluorescence and electrochemical impedance spectrum. • TPP-GO-ZnPc ternary nanohybrid was prepared. • The ternary nanohybrid exhibits enhanced optical limiting and HER. • The improved performance is assigned to a combination of mechanisms. [ABSTRACT FROM AUTHOR]

• Porphyrin coordination polymer (TiCP-PCP) decorated Co 1−x S composite was designed. • The introduction of TiCP-PCP provides abundant active sites for oxygen evolution. • The composite exhibits excellent electrocatalysis with ultralow overpotential. • The improved electrocatalysis is assigned to a combination of mechanisms. It is very imperative to develop cost-effective nonprecious-metal-containing materials with efficient oxygen evolution reaction (OER) activity. Herein, a series of novel composite catalysts (TiCP-PCP@Co 1−x S) by coupling Co 1−x S with porphyrin based porous titanium coordination polymer (TiCP-PCP) was designed and prepared, and was characterized by different spectroscopic techniques. The introduction of TiCP-PCP can significantly increase the number of active sites and tune the electronic structure of Co 1−x S to reach affluent surface Co3+ active sites center for boosting OER intrinsic activity. The present study indicates that there is an optimum concentration of TiCP-PCP in the composites to maximize OER performance; the optimized 0.2TiCP-PCP@Co 1−x S composite with 20 wt% TiCP-PCP exhibits the best OER activity with a low overpotential of 157 mV at a current density of 10 mA cm−2 and excellent long-term stability in alkaline solution. The OER performance of 0.2TiCP-PCP@Co 1−x S outperforms state-of-the-art nonprecious-metal catalysts (i.e. IrO 2 and RuO 2) and most previous reported cobalt-based catalysts. [ABSTRACT FROM AUTHOR]

Herein, a novel porous titanium coordination polymer (TiCP-PCP) with push-pull motif is prepared through the transesterification reaction of catechol porphyrin with titanium tetraisopropoxide. TiCP-PCP demonstrates efficient electrocatalytic activity toward HER/OER with prominent electrochemical durability in acid/basic medium. Surprisingly, TiCP-PCP requires relatively low overpotentials of 339 and 310 mV to reach a catalytic current density of 10 mA cm−2 for HER and OER, respectively. Based on experimental and theoretical results, the improved electrocatalytic performances for TiCP-PCP in comparison with those of TPP and TiO 2 are ascribed to efficient charge transfer and positive synergistic effect, stemming from the interactions between porphyrin units and Ti entities. This work can be readily extended to a wide range of porous coordination polymer-based electrochemical devices and catalysts design. A novel porous titanium coordination polymer with push-pull motif was designed and prepared through the transterification reaction of catechol porphyrin with titanium tetraisopropoxide. TiCP-PCP demonstrated efficient electrocatalytic activity toward HER/OER with prominent electrochemical durability in acid/basic medium. Image 1 • A novel porous titanium coordination polymer with push-pull motif was designed. • This polymer can provide abundant active sites for hydrogen and oxygen evolution. • The prepared polymer exhibited excellent electrocatalysis. • The improved electrocatalysis was assigned to a combination of mechanisms. [ABSTRACT FROM AUTHOR]

Two porphyrins functionalized single-walled carbon nanotube nanohybrids (SWCNT-TPP and SWCNT-TPPZn) have been prepared following the free radical addition reaction and subsequent nucleophilic substitution. The results of microscopic structure and morphology analysis, including Fourier transform infrared spectroscopy, transmission electron microscopy, X-ray photoelectron spectroscopy and thermogravimetric analysis, confirmed the successful fabrication of SWCNT-TPP and SWCNT-TPPZn nanohybrids. UV–vis absorption, Raman and fluorescence emission studies indicate considerable π-π interactions and effective charge transfer from the porphyrin moieties to the SWCNT. Z -scan investigations show that both nanohybrids exhibit improved nonlinear optical performances in the ns and fs regimes compared to those of individual SWCNT and porphyrins; this is proposed to result from a positive synergistic effect between SWCNT and porphyrins. Due to more effective charge transfer effect, SWCNT-TPP nanohybrid exhibit the best NLO performance at 532 and 800 nm. Unlabelled Image • Two metal-free and metal porphyrins covalently functionalized SWCNT are prepared. • Nonlinear optical modification of SWCNT is achieved by chemical functionalization. • The enhanced optical nonlinearity is mainly due to efficient charge transfer. [ABSTRACT FROM AUTHOR]

• A series of BiOBr@polyaniline-MnO 2 composites was synthesized. • The photocatalysis is shown to be dependent on the polyaniline-MnO 2 loadings. • The efficient photocatalysis was ascribed to the effective charge transfer effect. The development of effective sunlight-driven photocatalytic system for the removal of antibiotics has attracted great attentions in environmental remediation. In the present case, the BiOBr@polyaniline-MnO 2 (BOB/Mn-PANI) nanocomposites loaded with different Mn-PANI contents as efficient photocatalysts have been prepared successfully via the hydrothermal method. The introduction of Mn-PANI has a significant influence on the photocatalytic performance of the as-prepared samples. The BOB/0.50Mn-PANI composite with 0.50 wt% Mn-PANI exhibits the best photocatalysis for the degradation of ciprofloxacin (CIP) under simulated sunlight irradiation. The photodegradation kinetics and mechanisms of the as-prepared nanocomposites were investigated in detail to explain the influence of PANI and MnO 2 loadings on the removal efficiency of CIP. The fluorescence spectra and photoelectrochemical experiments indicated that the highly enhanced photocatalytic efficiency can be ascribed to the efficient photo-generated electron-hole separation and transmission. The radical trapping experiments suggested that ·O 2 − and h+ are the main reactive species for the photodegradation of CIP. This work provides an effective way to design novel photocatalysts with efficient performance under simulated sunlight. [ABSTRACT FROM AUTHOR]

Benefiting from the strong electronic interactions between the triazine unit and the CoTAPP moiety, a standard current density at 10 mA cm−2 is obtained for CoTAPPCC with a smaller overpotential of 150 mV in acid, which is comparable to or better than the best records reported previously. [Display omitted] Hydrogen production obtained by electrocatalytic water splitting exhibits great promise in addressing both energy shortage and environmental contamination. Herein, we prepared a novel cobalt porphyrin (CoTAPP)-bridged covalent triazine polymer (CoTAPPCC) by covalently linking CoTAPP with cyanuric chloride (CC) for catalytic hydrogen evolution reaction (HER). Both experimental techniques and density functional theory (DFT) calculations were used to evaluate the correlation of HER activity with molecular structures. Benefiting from the strong electronic interactions between the CC unit and the CoTAPP moiety, a standard current density at 10 mA cm−2 is obtained for CoTAPPCC with a low overpotential of 150 mV in acid, which is comparable to or better than the best records reported previously. Additionally, a competitive HER activity in basic medium is obtained for CoTAPPCC. The strategy reported herein is valuable for designing and developing porphyrin-based efficient HER electrocatalysts. [ABSTRACT FROM AUTHOR]

Highlights • The g-C 3 N 4 /CNHM hybrids with various weight ratios were prepared. • The g-C 3 N 4 /CNHM-2% hybrid exhibited the optimal photocatalytic performance. • Efficient optical nonlinearity was observed for g-C 3 N 4 /CNHM-2%. • The enhanced activity was attributed to the efficient charge transfer effect. Abstract In this study, a series of carbon nitride nano-homojunction (CNHM) decorated carbon nitride (g-C 3 N 4) nanocomposites (g-C 3 N 4 /CNHM) was synthesized by the facile solvothermal method to maximize the photocatalytic and nonlinear optical performances. The structure, optical and electrical properties of the g-C 3 N 4 /CNHM nanocomposites were investigated by various characterization techniques, including Fourier-transform infrared, X-ray photoelectron spectroscopy, X-ray diffraction patterns, Scanning electron microscopy, UV–Vis diffuse reflection spectra and Brunauer-Emmett-Teller method. The photocatalysis and nonlinear optical performance of the g-C 3 N 4 /CNHM nanocomposites are shown to be dependent on the CNHM loadings. The highest photocatalytic activity and obvious nonlinear optical performance were observed for g-C 3 N 4 /CNHM-2%. A rational mechanism for degrading pollutants and observed nonlinear property was proposed, which could be ascribed to the efficient interfacial charge transfer between g-C 3 N 4 and CNHM. The efficient charge separation efficiency was confirmed by the photoluminescence spectroscopy, electrochemical impedance spectroscopy, and photocurrent spectroscopy studies. These results indicate that the multifunctional hybrid materials with tunable optoelectronic performances can be obtained by adjusting the content of CNHM in g-C 3 N 4 /CNHM nanocomposites. [ABSTRACT FROM AUTHOR]

Porphyrin‐functionalized multi‐walled carbon nanotubes (MWCNTs) have been prepared through 1,3‐dipolar cycloaddition reactions. Covalent attachment of porphyrins to the MWCNTs' surfaces affords composite materials with excellent solubility and facile processing. These MWCNT–porphyrin nanohybrids exhibit strong optical limiting of both nanosecond and picosecond laser pulses at 532 nm, attributed to a combination of nonlinear scattering, reverse saturable absorption, and photoinduced energy transfer. For more information, see the Full Paper by C. Zhang et al. on page 14159 ff. [ABSTRACT FROM AUTHOR]

Review: 66 refs. [ABSTRACT FROM AUTHOR]

One novel tin porphyrin covalently functionalized polyaniline nanohybrid (SnTPP-PANI) has been prepared by the nucleophilic substitution reaction of polyaniline (PANI) with tin porphyrin (SnTPP). The attachment of SnTPP to PANI was confirmed by a series spectroscopic techniques, including ultraviolet/visible absorption, fluorescence, Fourier transform infrared spectroscopy, Raman and thermogravimetric analysis, transmission electron microscopy, and X-ray photoelectron spectroscopy. The Z-scan measurements indicate that SnTPP-PANI nanohybrid exhibits increased nonlinear optical (NLO) properties (including NLO absorption, nonlinear refraction and optical limiting) at 532 nm in comparison with those of PANI, SnTPP, and SnTPP/PANI blends. The enhanced NLO performances are ascribed to the remarkably efficient electron/energy transfer and the synergistic effect as a result of the covalent linkage between SnTPP and PANI. [Display omitted] • One tin porphyrin covalently functionalized polyaniline (SnTPP-PANI) was prepared. • SnTPP-PANI exhibits enhanced optical nonlinearities. • Synergistic effect between each component contributes to the nonlinear optics. [ABSTRACT FROM AUTHOR]

Rational design of efficient hydrogen evolution reaction (HER) electrocatalysts, constructed with earth-abundant elements, is critical for developing sustainable alternative energy sources. Herein, two phosphonitrilic-bridged metal porphyrin porous covalent organic polymers (COPs) were developed for HER. Compared to CoTPP-PCTCOP, NiTPP-PCTCOP exhibits relative low overpotentials of 140 to reach 10 mA cm−2 for HER in alkaline medium, which is comparable to many previously reported state-of-the-art electrocatalysts. The enhanced HER activity of NiTPP-PCTCOP is associated with its chemical composition and special push-pull structure. Long-term stability analysis of NiTPP-PCTCOP shows that the current density exhibits no obvious deactivation over a long time test. This work demonstrates an effective technique to develop promising HER electrocatalysts, highlighting its advantages by combing phosphonitrilic chloride trimer with metal porphyrins. [Display omitted] • Two phosphonitrilic-bridged metal porphyrin COPs were developed for HER. • NiTPP-PCTCOP exhibits relative low overpotentials of 140 to reach 10 mA cm−2. • The effective HER activity is associated with its special push-pull structure. [ABSTRACT FROM AUTHOR]

• Tunable oxygen reduction reaction properties is achieved by varying the electrolyte pH. • An A3B-type cobalt porphyrin-coated carbon black is designed as the catalyst. • Five electrolytes with pH values spanning from 0.7 to 13.7 are studied. • The composite exhibits the most positive potentials and the lowest Tafel slope at pH13.7. • Poor activity but high selectivity for 4-electron ORR is obtained at pH3.7. Understanding the pH-dependent mechanism of metalloporphyrin-based composite electrocatalystic oxygen reduction reactions (ORRs) can provide the basis for rational porphyrin molecular design. Tunable ORR properties of a cobalt porphyrin-based composite catalyst aFP-TCoP/C is accomplished by adjusting the electrolyte pH values spanning from 0.7 to 13.7. The composite performs the best ORR reactivity in the pH13.7 electrolyte, exhibiting the most positive characterized potentials (the ORR reduction potential E ORR of 0.76 V and the half-wave potential E 1/2 of 0.80 V) and the smallest Tafel slope of 43.1 mV dec−1. Whilst the sample with the pH3.7 electrolyte displays quite negative reduction potentials and a large Tafel slope, it exhibits an electron transfer number of 3.84, which indicates a nearly 4-electron transfer selectivity. The findings provide a practical protocol for regulating the catalytic reactivity and selectivity of ORRs by adjusting the components of electrolytes. [Display omitted] [ABSTRACT FROM AUTHOR]

Herein, the preparation of CoSe@NiSe2@MoS2 composites and the systematic investigation of their water splitting performance as a function of composition have been demonstrated. CoSe@NiSe2@MoS2-12 with the optimized composition exhibits a current density of 10 mA cm−2 at overpotentials of 81 and 170 mV for HER and OER in alkaline conditions, respectively. The overall water splitting device built using CoSe@NiSe2@MoS2-12 exhibited a low voltage of 1.48 V at 10 mA cm−2 due to the synergistic effects. [ABSTRACT FROM AUTHOR]

Four chiral porphyrins and their derivatives with chiral-amide-bonded terminal pyrene were synthesized and isolated. Structural characterization as well as electronic structure investigations were carried out to understand the effect of bridging an amide-bond on the molecular chirality. It has been clearly demonstrated that the nonlinear optical behaviors could be enhanced by surface orderly arrangement arising from introducing terminal pyrene units resulting in an efficient charge transfer effect from the porphyrins to MWCNTs. [ABSTRACT FROM AUTHOR]

Abstract In this work, a series of pyrimidine/g-C 3 N 4 photocatalysts has been synthesized via a facile solvothermal method for the first time. The structure, elemental composition and morphology of the photocatalysts were characterized by FT-IR, SEM, XPS, N 2 adsorption-desorption isotherms and BET characterization methods. The photocatalytic activity of the pyrimidine/g-C 3 N 4 materials was investigated by the degradation of rhodamine solution under visible-light illumination. The pyrimidine/g-C 3 N 4 photocatalyst with 1 wt% of pyrimidine shows the highest photocatalytic activity for the degradation of RhB, which can be mainly ascribed to the effective interfacial charge transfer within the pyrimidine/g-C 3 N 4 photocatalyst and the cooperation effect of the excellent contact interface between g-C 3 N 4 and pyrimidine. The main active species during the photodegradation process are determined by the radical trapping experiments, proving that the superoxide radical (•O 2 −) and the hydroxyl radical (•OH) play the main role in the photocatalytic reactions. Highlights • A series of pyrimidine/g-C 3 N 4 photocatalysts has been synthesized. • The content of pyrimidine has a significant effect on the photocatalysis. • The enhanced photocatalysis is ascribed to the efficient charge transfer. [ABSTRACT FROM AUTHOR]

The interfacial charge transfer conditions are crucial for understanding the catalytic mechanism and thus developing high performing electrocatalysts. To justify the effects of support material and electrolyte on metalloporphyrin catalytic oxygen reduction reaction (ORR), we synthesize a symmetric triphenylamine (TPA) substituted cobalt porphyrin, nominated as s-TPA-CoP , and select carbon black and multi-walled carbon nanotubes as the supports to fabricate composite catalysts. The ORR performances are measured in both acidic and alkaline solutions. While the support material affects negligibly on reduction potentials, the stronger π-π stacking in s-TPA-CoP/CNT , as revealed by X-ray photoelectron spectroscopy measurements, leads to greater limiting current densities and larger electron transfer numbers as compared to s-TPA-CoP/XC in either electrolyte. Both composites perform better ORR activity but poorer 4-electron selectivity in base than in acid, whose origins are discussed from the aspects of interfacial charge states and inner- / outer-sphere electron transfer mechanisms. Strikingly, s-TPA-CoP/CNT exhibits an electron transfer number of 3.8 in acid, demonstrating the privilege of TPA as the substitution on monometallic cobalt porphyrins in chasing 4-electron transfer oxygen reduction. [Display omitted] • A triphenylamine substituted cobalt porphyrin is designed for ORR. • Carbon black and nanotubes are used as the support materials. • ORR activities are recorded in both acid and alkali electrolytes. • Stronger π-π stacking leads to greater ORR activity of the composites. • Both composites exhibit better ORR activity but poorer selectivity in base than in acid. [ABSTRACT FROM AUTHOR]