As an important organic photofunctional material, spirooxazine (SO) usually does not exhibit photochromism in the solid state since the intermolecular π–π stacking impedes photoisomerization. Developing photochromic SO in the solid state is crucial for practical applications but is still full of challenges. Here, a series of spirooxazine derivatives (SO1–SO4) with bulky aromatic substituents at the 4‐ and 7‐positions of the skeleton, which provide them with a large volume with which to undergo solid‐state photochromism under mild conditions, is designed and synthesized. All the compounds SO1–SO4 exhibit tunable solid photochromism without ground colors, excellent fatigue resistance, and high thermal stability. Notably, it takes only 15 s for SO4 to reach the saturation of absorption intensity, thought to represent the fastest solid‐state photoresponse of spirooxazines. X‐ray crystal structures of the intermediate compound SO0 and the products SO1–SO2 as well as computational studies suggest that the bulky aromatic groups can lead to a hypochromic effect, allowing for the photochromism of SO in the solid state. The ideal photochromic properties of these spirooxazines open a new avenue for their applications in UV printing, quick response code, and related fields.

No abstract

Because of the special layered structure and catalytic properties, delafossite CuCrO2 has been extensively studied and can obtain outstanding performance by noble metal coupling. In this work, the Ag-decorated CuCrO2 hybridizations have been elaborated by a thermal evaporation method. Surface morphology characterization and chemical state analysis were combined to indicate that the isolated island distribution of Ag nanoclusters and the generation of a divalent copper ion may result in an improvement in the gas response toward 100 ppm volatile organic compounds, such as formaldehyde (38.7%), methanol (56.8%), and acetone (76.3%). First-principle calculations were carried out to demonstrate the sensing mechanism of the Ag-decorated CuCrO2, where the remarkable change in geometry and electronic structure provided the active interface and noble metal catalysis effect promoting the target gas adsorption and reaction process. Therefore, in this work, we propose that the thermal evaporation can be utilized to act as a controllable modification method to construct nanostructure gas sensors, and the fundamental enhancement mechanism is useful to guide the design of efficient delafossite-based composite catalysts.

Tuning the thermal fading rate within several seconds while maintaining ideal colorability is a bottleneck problem for the industrial applications of photochromic naphthopyrans. Herein, a series of new photochromic 2,2,6-triaryl...

Nowadays, the high cost and poor durability of commercial catalyst Pt/C for methanol oxidation reaction have impeded the further development of direct methanol fuel cells. Herein, we firstly introduced a delafossite CuCoO2 to act as the support of noble metal Pt. The strong metal support interaction between Pt and CuCoO2, abundant hydroxide species and active sites on the surface of catalyst may be the key factors for enhanced performances of methanol oxidation. Pt‐CuCoO2/C achieved a mass activity of 1.16 A mgPt−1, which obtained 3.02 times enhancement compared with commercial Pt/C (0.38 A mgPt−1). The If/Ib value of Pt‐CuCoO2/C is 1.96, much higher than that of Pt/C (0.76), demonstrating favorable anti‐poisoning ability. After 200 times cycling, Pt‐CuCoO2/C still maintained 77.1 % of its initial activity, exhibiting superior COads intermediate tolerance and stability. Low cost, better performances and stability of Pt‐CuCoO2/C reveal that it can be seen as a hopeful catalyst.