Periodic porous alloyed Au-Ag nanosphere (NS) arrays with different periodic lengths and tunable composition ratios were prepared on Si substrates on a large scale (∼cm) using stepwise metal deposition-annealing and subsequent chemical corrosion from a monolayer of colloidal polystyrene (PS) microspheres as the initial template. The porous alloyed Au-Ag NSs possessed a high porosity and bicontinuous morphology composed of hierarchically interconnected ligaments, which were obtained from an optimized dealloying process in nitric acid. Interestingly, when the dealloying time was prolonged, the average size of the porous alloyed NSs slightly decreased, and the width of the ligaments gradually increased. The periodic length of the array could be facilely changed by controlling the initial particle size of the PS template. Moreover, the porous alloyed Au-Ag NS arrays were explored as a platform for the surface-enhanced Raman scattering (SERS) detection of 4-aminothiophenol (4-ATP) and exhibited excellent reproducibility and high sensitivity because of the periodic structure of the arrays and the abundance of inherent "hotspots". After optimization experiments, a low concentration of 10 M 4-ATP could be detected on these porous Au-Ag NS array substrates. Such highly reproducible SERS activity is meaningful for improving the practical application of portable Raman detection equipment.

We report the successful synthesis of Mo doped NiP nanowires (NWs) on a Ni foam (NF) substrate by a two-step strategy, which could be used as an efficient and stable hydrogen evolution reaction (HER) electrocatalyst over the whole pH range (0-14). Electrochemical investigations demonstrated that Mo doping made the catalytic activity of NiP significantly enhanced. To achieve a current density of 10 mA cm, Mo-NiP NWs/NF required an overpotential of 67 mV in acidic solution, 78 mV in alkaline solution and 84 mV in neutral solution. It also showed superior stability with negligible activity decay after its use in the HER under different pH conditions for 24 h. Such excellent HER activity might originate from the synergistic effect between molybdenum (Mo) and nickel (Ni) atoms. The present work provides a valuable route for the design and synthesis of inexpensive and efficient all-pH HER electrocatalysts.

Free-standing 2D Au nanosphere array/hydrogel composite films on an ordinary quartz substrate demonstrate a strong diffraction signal, which could improve their practical applications in visual detection.

Hierarchical hetero-Ni3Se4@NiFe LDH micro/nanosheets were prepared by coupling NiFe LDH nanosheets with Ni3Se4 micro-sized sheets, and could be used as bifunctional electrocatalysts with excellent activity and durability for overall water splitting.

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nMOFs embellished with an AuNP nanozyme have great potential to generate O2 for overcoming the tumor hypoxic microenvironment for photodynamic therapy.

The sponge-like Au–Ag alloy nanocubes (NCs) showed excellent SERS performance derived from high-density “hotspots” in nanopores, sharp corners and edges, and synergistic effect between Au and Ag species.