As conventional structural materials reach their performance limits, one of the major scientifi c challenges for the 21st century is the development of new high performance, multifunctional materials to support advances in diverse strategic fi elds, ranging from building and transportation to energy and biotechnology. [ 1 ] In the process of evolution, nature has found ingenious ways to produce lightweight, strong, and high-performance materials with exceptional properties and functionalities. [ 2 ] Biological materials, such as tooth, bone, and nacre, are complex, hierarchical, heterogeneous nanocomposites providing superior mechanical properties and biocompatibility. Thus, mimicking the architecture of natural/biological materials and structures is a viable approach for designing new materials.Naturally occurring nacre's remarkably high toughness and resilience, given its composition of brittle, inorganic CaCO 3 and biopolymer proteins, has been widely recognized. Nacre is twice as strong and 1000-fold tougher than its constituents. [3][4][5][6][7] Several mechanisms have been reported that contribute to the strength and toughness of nacre. [4][5][6][7] The layered arrangement of platelet-shaped CaCO 3 crystals and proteins into a "bricks-andmortar" structure is the key to nacre's outstanding mechanical properties. [ 8 ] Platelet-like inorganic building blocks are essential elements in biomimetic artifi cial composites, especially when one aims to create a layered "bricks-and-mortar" micro-and/or nanostructure. In previous studies, however, natural clay minerals, ceramic Al 2 O 3 platelets, and TiO 2 layers were used merely to fabricate biologically inspired composites with high mechanical performance without focusing on other functionalities, such as electrical conductivity and biocompatibility. [ 1-3 , 8-15 ] On the other hand, graphene has attracted considerable interest in recent years owing to its extraordinary material properties. [16][17][18] A two-dimensional lattice of sp 2 -bonded carbon that is only one-atom thick, graphene exhibits remarkably high electrical conductivity, thermal conductivity, and mechanical properties that rival the in-plane values of graphite, making it an excellent candidate as the " bricks" for fabricating nacre-like composites.To date, nanosheets of graphene oxide (GO) or reduced graphene oxide (RGO) have been used as nanofi llers to improve the mechanical and electrical properties of polymers, in which the fi ller content is usually lower than 10 wt%. [19][20][21][22][23][24] For these nanocomposites, full exploitation of the extraordinary properties of graphene is limited by low GO or RGO content. For instance, the highest electrical conductivity of RGO/polymer composites reported is 51.2 S m − 1 , [ 24 ] two orders of magnitudes lower than most pure RGO sheets. On the other hand, for nacre, the platelet-shaped CaCO 3 is the dominant phase with a high content of 95 vol%. [ 3 ] We report the preparation of bio-inspired, nacre-like reduced poly(vinyl alcohol)/graphene oxide (R...

Effective virtual screening relies on our ability to make accurate prediction of protein-ligand binding, which remains a great challenge. In this work, utilizing the molecular-mechanics Poisson-Boltzmann (or Generalized Born) Surface Area approach, we have evaluated the binding affinity of a set of 156 ligands to seven families of proteins, trypsin β, thrombin α, cyclin-dependent kinase (CDK), cAMP-dependent kinase (PKA), urokinase-type plasminogen activator, β-glucosidase A and coagulation factor Xa. The effect of protein dielectric constant in the implicit-solvent model on the binding free energy calculation is shown to be important. The statistical correlations between the binding energy calculated from the implicit-solvent approach and experimental free energy are in the range 0.56~0.79 across all the families. This performance is better than that of typical docking programs especially given that the latter is directly trained using known binding data while the molecular mechanics is based on general physical parameters. Estimation of entropic contribution remains the barrier to accurate free energy calculation. We show that the traditional rigid rotor harmonic oscillator approximation is unable to improve the binding free energy prediction. Inclusion of conformational restriction seems to be promising but requires further investigation. On the other hand, our preliminary study suggests that implicit-solvent based alchemical perturbation, which offers explicit sampling of configuration entropy, can be a viable approach to significantly improve the prediction of binding free energy. Overall, the molecular mechanics approach has the potential for medium to high-throughput computational drug discovery.

A poly(vinyl alcohol) (PVA) based nanocomposite using fully exfoliated graphene oxide (GO) sheets and multi-walled carbon nanotubes (CNTs) were prepared via a simple procedure. It is confirmed from optical imaging that dispersion of CNTs in the PVA matrix can be significantly improved by adding GO sheets. Molecular dynamics (MD) simulations suggest that the GO-CNT interaction is strong and the complex is thermodynamically favorable over agglomerates of CNTs. The GO-CNT scroll-like structure formed with the hydrophilic outer surface of GO can be well dispersed in water. More important, a synergistic effect arises from the combination of CNT and GO, the GO-CNT/PVA composite films show superior mechanical properties compared to PVA composite films enhanced by GO or CNT alone, not only the tensile strength and Young's modulus of the composites are significantly improved, but most of the ductility is also retained. The enhanced mechanical properties of the GO-CNT/PVA composite film can be attributed to the fully exploited reinforcement effect from GO and CNT via good dispersion.

With abundant crystal defects, cerium oxide (CeO2), widely used in heterogeneous catalysis, has attracted extensive attention. In recent years, researchers have investigated that the defect chemistry of CeO2 plays a vital role in its catalytic activity and have developed various defect introduction methods to synthesize stable and efficient defective CeO2‐based catalysts. Herein, the understanding, introduction, and applications of defect chemistry in CeO2‐based heterogeneous catalysis are reviewed, and the structure–activity relationship between defect engineering and catalytic performance is recommended with great emphasis. Interests are put into the investigation of how defects influence the activity and stability of defective CeO2 catalysts and effective strategies for fabricating efficient, stable, and defective CeO2 catalysts. Finally, the existing problems and perspectives of CeO2 defect chemistry for heterogeneous catalysis are displayed. This review provides a reference for in‐depth understanding and the design of more efficient CeO2‐based catalysts for heterogeneous catalysis.

Hydrogen economy based on electrochemical water splitting is one of the most prospective strategies to circumvent the rapid consumption of traditional fossil fuels. The development of efficient and durable electrocatalysts for water splitting plays a crucial role in the energy conversion and storage process. Nickel selenide (Ni x Se y ), as a typical multifunctional electrocatalyst, has attracted great consideration owning to its component diversity, high conductivity, and regulated morphology/electronic structures. In Ni x Se y , nickel has a unique valence electron configuration (3d84s2) and acts as the main catalytic activity site. Compared with S and O, Se in Ni x Se y not only has the same valence electrons and oxidation number but also has excellent intrinsic metal properties, which means better electrical conductivity and electrocatalytic activity. In addition, Ni and Se could form stoichiometric compounds (NiSe, NiSe2, Ni3Se2, Ni3Se4) and nonstoichiometric compounds (Ni0.85Se), which is ascribed to the electronegativity difference between Ni (1.9) and Se (2.4). In this review, the crystal structure, preparation methods, and practical applications of Ni x Se y -based electrocatalysts are summarized. The merits and limitations of nickel selenide are discussed in terms of structure and composition. Finally, the challenges and opportunities faced by NixSey-based electrocatalysts in water splitting are discussed.