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Polymeric g‐C3N4 is a promising visible‐light‐responsive photocatalyst; however, the fast recombination of charge carriers and moderate oxidation ability remarkably restrict its photocatalytic oxidation efficiency towards organic pollutants. To overcome these drawbacks, a self‐modification strategy of one‐step formaldehyde‐assisted thermal polycondensation of molten urea to prepare carbon‐deficient and oxygen‐doped g‐C3N4 (VC‐OCN) is developed, and the carbon vacancy concentration is well‐controlled by changing formaldehyde dosage. The VC‐OCN catalysts exhibit interesting carbon vacancy concentration‐dependent photocatalytic removal efficiency to p‐nitrophenol (PNP) and atrazine (ATN), in which VC‐OCN15 with appropriate carbon vacancy concentration displays significantly higher pollutant removal efficiency than bulk g‐C3N4. The apparent first‐order rate constant of VC‐OCN15 for PNP and ATN removal is 4.4 and 5.2 times higher than that of bulk g‐C3N4. A combination of the experimental results and theoretic calculations confirm that the synergetic effect of carbon vacancies and oxygen doping sites can not only delay the recombination of charge carriers but also facilitate adsorption of oxygen molecules on the carbon vacancies, which leads to the generation of plentiful active oxygen species including not only superoxide anion radicals but also indirectly formed hydroxyl radicals and singlet oxygen. These active oxygen species play a dominant role in the removal of target pollutants.

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To improve the photocatalytic hydrogen evolution activity of palladium-assisted graphitic carbon nitride (g-C3N4), here, palladium-single-atom-coordinated cyano-group-rich g-C3N4 (Pd/DN-UCN) are synthesized, and the synthesis process includes copolymerization of urea-derived supramolecular aggregates and NH4Cl followed by wet impregnation. By combining powerful characteristic results and theoretical calculations, the formation mechanism of Pd single atoms on the ultrathin, mesoporous cyano-group-rich g-C3N4 nanosheets is proposed, highlighting that the Pd single atoms are firmly stabilized in the interlayers of g-C3N4 nanosheets caused by the combination of the physical confinement effect of ultrathin, mesoporous g-C3N4 nanosheets and coordination bonding of cyano groups with Pd atoms; additionally, Pd–N3 coordination in the Pd/DN-UCN heterojunctions is confirmed, in which one Pd atom coordinates with one N atom of the cyano group and two sp2-hybridized N atoms in the adjacent layer. The presence of cyano groups and Pd–N coordination in the Pd/DN-UCN induces a midgap state in the band structure of g-C3N4. At optimal Pd loading levels (0.16%), the synthesized 0.16%Pd/DN-UCN0.50 exhibits enhanced photocatalytic hydrogen production activity as compared to electrostatically stabilized Pd single atoms on the “sixfold cavities” of g-C3N4, and apparent quantum yield values at the stationary point of the 0.16%Pd/DN-UCN0.50 concentration (1.2 g L–1) can reach up to 14.6, 15.8, 4.69, and 3.05% under monochromatic light irradiation at 365, 400, 450, and 550 nm, respectively. The cooperation of significantly boosted transfer of photoexcited electrons to atomically dispersed Pd sites via as-built interlayer Pd–N coordination delivery channels and the maximal Pd atom utilization efficiency dominates the enhanced photocatalytic hydrogen evolution activity of Pd/DN-UCN.

We study the confinement of polysoaps in lyotropic smectic (L a ) and sponge (L 3 ) solutions of the nonionic surfactant pentaethylene glycol dodecyl ether (C 12 EO 5 ). The polysoap is a hydrophobically modified polymer with n-tetradecyl sidegroups randomly grafted to a polyacrylate backbone. Without the hydrophobic side chains the backbone polymer cannot be embedded into the intermembrane space, but confinement is achieved for a polysoap with as low as 1% of grafted groups. We measure by small angle x-ray and neutron scattering an increase of the bending rigidity of the lamellar membranes as a function of polysoap concentration. [S0031-9007(98)05642-7] PACS numbers: 83.70.Hq, 64.75. + g, 82.65.DpFluid membranes are two-dimensional structures, selfassembled from surfactant solutions [1]. In the biological realm, phospholipid bilayers constitute the walls of liposomes and cells, hosting proteins responsible for functions as diverse as anchoring the cytoskeleton, providing coating protection against the body immune response or opening ionic channels for osmotic compensation [2]. Membranes are also present in many surfactant based industrial formulations. For instance, the processing and delivery of detergents or conditioning agents often require at some stage the use of concentrated surfactant solutions where lyotropic liquid crystals are formed [3]. The simplest liquid crystalline phase of membranes is the lamellar phase L a , a smectic A lyotropic liquid crystal [4]. It consists of one-dimensional stacks of surfactant bilayers, separated by a solvent. Its one-dimensional symmetry allows for a relatively straightforward experimental determination of many properties pertaining not only to the ordered phase as a collective body of interacting membranes but also to each individual bilayer with its intrinsic constitutive elasticity [5]. Also of interest for our study is the sponge phase L 3 , a bicontinuous isotropic phase of multiconnected membranes [6]. The wealth of information collected over the past two decades on L a and L 3 phases designates them as convenient tools to investigate interactions between membranes and other components often present in synthetic or naturally occurring colloidal suspensions. L a phases have for instance been used to host ferromagnetic colloidal particles [7] and different types of polymers [8][9][10][11], both in the intermembrane solvent subphase [12,13] and inside the bilayer itself [14]. In this Letter we investigate by small angle x-ray and neutron scattering the structure of L a and L 3 phases with embedded polysoaps, a particular class of macromolecular surfactants. By studying a system of very flexible membranes, we were able to quantitatively determine, for the first time, the variation of the elastic constant of the membranes as a function of the concentration of added polymer.The L a and L 3 phases under investigation are composed of membranes of the nonionic surfactant C 12 EO 5 (from Nikko, Japan) and hexanol in a NaCl brine solution at 0.1M. Pure water͞C 12 EO 5 mixtur...