The adsorption states of NH 3 molecules and NH 4 + ions on various sites, such as hydroxyl, H + and Na + , of ZSM-5 zeolites with different SiO 2 /Al 2 O 3 ratios were investigated by near and middle infrared spectroscopy.For Na + -type and siliceous ZSM-5 zeolites, only hydrogen-bonded NH 3 clusters were observed at 5021and 4519 cm −1 , due to the lack of Brönsted acid sites. The NH 3 molecules interacting with the hydroxyl groups easily desorbed at room temperature (r.t.), while the molecules interacting with the Na + sites desorbed at 473 K. For the H + -type ZSM-5, when NH 3 adsorption amount was small, the NH 4 + formed on the H + sites as well as the NH 3 adsorbed on the H + (or possibly Al 3+ ) sites were independently observed at 4846 and 5044 cm −1 , respectively. As the amount of NH 3 adsorption increased, the NH 4 + stabilized by the 2nd layer of NH 3 molecules as well as the hydrogen-bonded NH 3 clusters were observed at 4782 and 5017 cm −1 , respectively. The hydrogen-bonded NH 3 molecules desorbed at lower than 423 K but the NH 4 + ions decomposed at 573-623 K to form Brönsted acid sites.Catal. Sci. Technol. This journal is

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Abstractπ‐Conjugated copolymers consisting of squaraine dyes as light‐harvesting components and phenylene linkers (PSQ) are presented. They show intense absorption in visible (Vis) and near‐infrared (NIR) region, originating with the intramolecular charge transfer of the dye. Although their optical and electrochemical properties are dominantly derived from dye components, phenylene linkers affect aggregation in the solid state and phase segregation of the PSQ/PCBM composites. Bulk heterojunction solar cells consisting of PSQ/PCBM exhibit spectral response in Vis–NIR region, and they show power conversion efficiencies up to 0.64%. The copolymer approach to develop squaraine‐based polymers enables the auxiliary tuning of the physical properties that determine photovoltaic performance through the choice of linkers.

In order to understand the acidity properties of hydrated ZSM-5 zeolites having different SiO 2 /Al 2 O 3 ratios, the adsorption states of the NH 3 and NH 4 þ species on hydrated ZSM-5 zeolites were concurrently investigated by near infrared spectroscopy. In the case of hydrated H þ-type ZSM-5, absorption band due to the H 2 O molecules directly interacting with the H þ sites (Brønsted acid sites) was observed at 5266 cm À1. When the NH 3 molecules were admitted on the hydrated H/ZSM-5, absorption bands due to isolated NH 3 and isolated NH 4 þ were simultaneously observed at 5044 and 4846 cm À1 , respectively, although most of the H þ sites were occupied by H 2 O molecules. As the NH 3 adsorption amount increased, almost isolated H 2 O molecules hardly changed while the NH 3 and NH 4 þ stabilized by the hydrogen bonds shifted to 5000 and 4771 cm À1 , respectively. As for the siliceous-type ZSM-5, near infrared absorption due to H 2 O molecules interacting with the silanol groups was mainly observed at 5285 cm À1. However, since the H 2 O molecules readily desorbed at r.t. due to the hydrophobic character of the siliceous zeolite surface, the NH 3 adsorption behavior was almost the same as the dehydrated sample. In the case of Na þ-type ZSM-5, absorption band due to H 2 O molecules directly interacting with the Na þ sites was observed at 5291 cm À1. When NH 3 molecules were adsorbed on the hydrated Na/ZSM-5, absorption band due to the hydrogen-bonded H 2 O shifted to 5260 cm À1 and absorption band due to the NH 3 molecules in the NH 3 /H 2 O mixed clusters was simultaneously observed at 5014 cm À1. When the NH 3 /H 2 O mixed clusters desorbed from Na/ZSM-5, an absorption band due to NH 3 species interacting with the Al 3þ sites (Lewis acid sites) was observed at 4957 cm À1 since the neutral Na/ZSM-5 surface might be dealuminated by the basicity of the wet NH 3 clusters. Keywords Near infrared spectroscopy, adsorption of NH 3 and NH 4 þ , H þ and Na þ-type ZSM-5 zeolites, hydrated surface