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However, its STH efficiency is greatly plagued by its limited light absorption, poor charge transport, and sluggish water oxidation kinetics. [2] In this context, recent research has focused on overcoming these intrinsic issues, including N 2 or H 2 treatment for improved light harvesting, [3] heteroatom doping for increasing charge carrier densities and thus charge transport, [4] and oxygen evolution cocatalyst (OEC) loading for facilitating the reaction kinetics. [5] Despite the effectiveness of the above methods, a simple route to synchronously improve the three processes for enhanced PEC photoanode performance of photoanode is highly desirable. This has yet to be largely explored.The operation temperature has been proven to be exert a profound influence on the bandgap of semiconductors, hole diffusion length of photoanodes and electrocatalytic properties of OECs. [6] For example, the absorption band of semiconductor quantum dots was found to exhibit a red shift with increasing temperature. [7] Minority carrier hopping was activated within BVO photoanodes via a moderate temperature elevation of the electrolyte, resulting in efficient bulk charge separation. [8] Furthermore, the electrocatalytic performance of OECs could be greatly enhanced by magnetic heating in an external high-frequency alternating magnetic field. [9] Inspired by the above intriguing results, it The ability of photoanodes to simultaneously tailor light absorption, charge separation, and water oxidation processes represents an important endeavor toward highly efficient photoelectrochemical (PEC) water splitting. Here, a robust strategy is reported to render markedly improved PEC water splitting via sandwiching a photothermal Co 3 O 4 layer between a BiVO 4 photoanode film and an FeOOH/NiOOH electrocatalyst sheet. The deposited Co 3 O 4 layer manifests compelling photothermal effect upon near-infrared irradiation and raises the temperature of the photoanodes in situ, leading to extended light absorption, enhanced charge transfer, and accelerated water oxidation kinetics simultaneously. The judiciously designed NiOOH/ FeOOH/Co 3 O 4 /BiVO 4 photoanode renders a superior photocurrent density of 6.34 mA cm -2 at 1.23 V versus a reversible reference electrode (V RHE ) with outstanding applied bias photon-to-current efficiency of 2.72% at 0.6 V RHE . In addition to the metal oxide, a wide variety of metal sulfides, nitrides, and phosphides (e.g., CoS, CoN, and CoP) can be exploited as the heaters to yield high-performance BiVO 4 -based photoanodes. Apart from BiVO 4 , other metal oxides (e.g., Fe 2 O 3 and TiO 2 ) can also be covered by photothermal materials to impart significantly promoted water splitting. This simple yet general strategy provides a unique platform to capitalize on their photothermal characteristics to engineer high-performing energy conversion and storage materials and devices.

A main-chain elastomer was synthesized for the first time by a cross-linking hydrosilylation of a cyclosiloxane with a new main-chain liquid crystalline semiflexible polyether. Imposing a uniaxial mechanical field to the unstretched nematic polydomain sample results in a macroscopic alignment of the director. For this process the sample has to be stretched by a factor of about 5, which considerably exceeds the effect observed for nematic side-chain elastomers.

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Assisted by NIR light, the obtained Co-Pi/PANI/BiVO4 photoanode achieves a remarkable water oxidation photocurrent of 4.05 mA cm−2 at 1.23 VRHE.

Head-to-head regioregular poly(p-phenylene)s (PPPs) were synthesized via Ni(0)-catalyzed polymerization of 2,2‘-disubstituted 4,4‘-bis[(methylsulfonyl)oxy]biphenyls (9). The corresponding regioirregular PPPs were prepared by the Ni(0)-catalyzed homopolymerization of 2-substituted 1,4-bis[(methylsulfonyl)oxy]benzenes (6) and by copolymerization of 6 with 9. The precursors of 6 and 9, i.e., 2-substituted 1,4-dihydroxybenzene (5) and 2,2‘-disubstituted 4,4‘-dihydroxybiphenyl (8), were synthesized by a synthetic method elaborated previously in our laboratory [J. Org. Chem. 1995, 60, 1066]. Head-to-head regioregular PPPs are crystalline and insoluble (except when the substituent is 4-tert-butylbenzoyl) while the corresponding regioirregular polymers are noncrystalline and soluble. The highest molecular weight regioirregular PPP was obtained by copolymerization of a 1:1 ratio of 6 with the corresponding 9. The influence of the size and the electronic properties of the substituent on the reactivity of monomers 6 and 9 and on the molecular weight of the regioirregular PPP is discussed. The highest molecular weight (M n = 34 790, corresponding to 176 phenylene groups relative to polystyrene standards) regioirregular PPP was obtained with a 4-fluorobenzoyl substituent. Fluorine both influences the reactivity of the leaving group and acts as more than one substituent since the hydrogen(s) ortho to it is (are) acidic.

Regioirregular poly(p-phenylene)s (PPPs) with OCF3, CF3 or OCH3 substituents (16a, 16b, or 16c, respectively) were synthesized via Ni(0)-catalyzed polymerization of 2-substituted-1,4-bis-[[(trifluoromethyl)sulfonyl]oxy]benzenes (5, 8, or 10, respectively). Regioregular head-to-head PPPs with OCF3 or CF3 substituents (17a or 17b) were prepared from 2,2′-disubstituted-4, 4′-bis[[(trifluoromethyl)sulfonyl]oxy]biphenyls 14a, 14b and 2,2′-disubstituted-4,4′-bis[methylsulfonyl)oxy]biphenyls 15a, 15b. Regioregular head-to-head statistical copolymers with combinations of OCF3 or CF3 substituents with OCF3, CF3, CO(p-FC6H5), CH3, or H substituents (17xy) were synthesized by the copolymerization of 15a or 15b with 2,2′-disubstituted-4,4′-bis[(methylsulfonyl)oxy]biphenyls 15a-15e. Regioirregular and regioregular PPPs with OCF3 or CF3 substituents were soluble (THF, CHCl3, dipolar aprotic solvents). The highest molecular weight PPPs were obtained from OCF3-substituted monomers. Regioirregular PPP (16a) with Mn ) 35 200 (corresponding to 220 phenylene groups relative to polystyrene standards) was obtained from 5. Regioregular PPP (17a) with Mn ) 54 500 (340 phenylene units) was obtained from 14a. Regioregular PPP copolymers (17ab) with Mn ) 55 200 (363 phenylene units) were obtained from copolymerization of 15a and 15b. The λmax values of OCF3-and CF3-substituted PPPs were 302-307 and 273-271, respectively. A 10% weight loss occurs in the range of 550-575 °C for PPPs with OCF3 substituents and 580-615 °C for those with CF3 substituents. Polymers 17a, 17b, and 17ab exhibit enantiotropic nematic and lyotropic mesophases. The thermotropic nematic phase of 17a, 17b, and 17ab is stable up to the decomposition temperature. Most probably, 17a and 17b also exhibit a second mesophase which is monotropic and becomes enantiotropic in 17ab. The rigid-rod character of these polymers was demonstrated by the Mark-Houwink coefficient a ) 1.58-1.60. Phosphorus was not detected (MALDI and 31 P NMR) in the structure of these homopolymers and copolymers.

This paper reports the elaboration of a novel synthetic method for the preparation of polyphenylenes. It consists of the Ni(0)-catalyzed polymerization of bis[(methylsulfonyl)oxy] derivatives (i.e., arylene bismesylates) of substituted hydroquinones. The Ni(0) catalysts used were generated in situ from NiCMPPhsh, Zn, Et*NI in THE, dioxane, or DMAc. The influence of solvent, temperature, additional ligands, and the size and electronic properties of the substituent groups of the monomers on their polymerizability was investigated. Soluble poly(p-phenylene)s and poly(m-phenylene)s can be obtained by a proper selection of their substituents. Poly(p-phenylene)s with number-average molecular weights (relative to polystyrene standards) of up to 20 030 (DP = 101) were obtained.