Visible-light-assisted multimechanism design for one-step engineering tough hydrogels in seconds.

Tough hydrogels that are capable of efficient mechanical energy dissipation and withstanding large strains have potential applications in diverse areas. However, most reported fabrication strategies are performed in multiple steps with long-time UV irradiation or heating at high temperatures, limiting their biological and industrial applications. Hydrogels formed with a single pair of mechanisms are unstable in harsh conditions. Here we report a one-step, biocompatible, straightforward and general strategy to prepare tough soft hydrogels in a few tens of seconds under mild conditions. With a multimechanism design, the network structures remarkably improve the mechanical properties of hydrogels and maintain their high toughness in various environments. The broad compatibility of the proposed method with a spectrum of printing technologies makes it suitable for potential applications requiring high-resolution patterns/structures. This strategy opens horizons to inspire the design and application of high-performance hydrogels in fields of material chemistry, tissue engineering, and flexible electronics.

First-principles calculations and experimental investigation on SnO2@ZnO heterojunction photocatalyst with enhanced photocatalytic performance.

In this study, branch-like SnO2@ZnO heterojunction photocatalyst was successfully fabricated via a simple two-step hydrothermal process. The optical and electronic properties were characterized in detail and the results indicated that SnO2@ZnO nanocomposites (TZNCs) exhibited superior photocatalytic performance under visible light irradiation as compared to pure SnO2 and ZnO. The excellent photocatalytic performance of TZNCs can be ascribed to the heterojunction structure between ZnO and SnO2 which depresses the recombination of photogenerated electron-hole pairs. In addition, the branch-like morphology can provide large specific surface. Moreover, the density functional theory (DFT) computation on the Fermi level results confirmed that heterojunction structure between ZnO and SnO2 is more favor of the transfer of photogenerated eletrons from ZnO to SnO2, effectively improving separation of photogenerated electron-hole pairs. Noteworthy, this work would pave the route for the two semiconductor materials with a big work function difference which would lead to the high contact potential difference, surely contributing to improving the performance of photocatalysts.