Cu-Doped CoP Nanorod Arrays: Efficient and Durable Hydrogen Evolution Reaction Electrocatalysts at All pH Values

We report a simple method for preparation of self-supported nanoporous Cu-doped CoP nanorod arrays on carbon cloth (Cu-CoP NRAs/CC) by a hydrothermal and low-temperature phosphidation process, which demonstrates enhanced catalytic performance over a wide pH range. This Cu-CoP NRAs/CC electrode shows a good HER performance with an overpotential of 44 mV to achieve current density of 10 mA cm^–2 in 0.5 M H₂SO₄. To get the same current density, it requires overpotentials of 81 mV in 1.0 M KOH and 137 mV in 1.0 M PBS, respectively. It also maintains a stable catalytic activity under different pH condition for 40 h. Such superior HER performance could be attributed to the strong heteroatomic interactions prompted lots of lattice distortions and defects, further provided many effective reactive sites on the nanorods. Such Cu-CoP NRAs/CC provides us highly efficient materials for water-splitting devices in industrial hydrogen production

Periodic Porous Alloyed Au–Ag Nanosphere Arrays and Their Highly Sensitive SERS Performance with Good Reproducibility and High Density of Hotspots

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 (∼cm²) 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^–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