RESUMO
Popcorn nanoparticles (pop-NPs) consisting of a Pd/Cu alloy were synthesized using a seed-mediated growth method. The Cu and Pd atoms were co-deposited on a cubic Pd seed to reduce the energy of fault stacking. The same synthesis method with a reduced volume of the Cu(II) salt leads to Pd/Cu alloy nanoparticles with branches (br-NPs). Large Pd nanocubes (Pd NCs) were prepared via epitaxial deposition and using tetrachloropalladate (PdCl42-) only. The high-resolution TEM analysis results show the pop-NPs and br-NPs to be single crystals with [Formula: see text] and [Formula: see text] planes, respectively. The results of X-ray photoelectron spectroscopy and cyclic voltammetry measurements corroborated that Pd is enriched on both surfaces. The materials were placed on a glassy carbon electrode to obtain a differential pulse voltammetric sensor for dopamine (DA). The electrochemical sensitivities are (a) 1.55 µA µM-1 cm-2 for the Pd/Cu pop-NP sensor in its linear range (15-300 µM), (b) 1.17 µA µM-1 cm-2 for the br-NP sensor in the linear range (15-200 µM), and (c) 0.97 µA µM-1 cm-2 for the Pd NC sensor in its linear range (15-100 µM). The best working potentials are near 0.10 V (vs. SCE) for all three sensors. The pop-NP-based sensor performs particularly well due to it selectivity over ascorbic and uric acid. Graphical abstract Pd/Cu popcorn nanoparticles (pop-NPs), nanoparticles with branches (br-NPs), and Pd nanocubes (NCs) were synthesized using seed-mediated growth methods and directly used on glassy carbon electrodes for non-enzymatic sensing of dopamine.