In situ synthesis by organometallic method of vulcan supported PdNi nanostructures for hydrogen evolution reaction in alkaline solution

Pd and Pd-based catalysts for hydrogen production remain the best alternative to Pt substitution because of similarities in their electronic structure and more abundant reserves. In this work, it was carried out the in-situ synthesis of Pd_xNi_1-x/C electrode materials (x = 0, 30, 50, 70 and 100 wt%) by the displacement of ligands from organometallic compounds followed by an annealing process at 300 °C in Ar atmosphere. The electrocatalytic performance of these materials was evaluated on the hydrogen evolution reaction in alkaline medium (1 M KOH). The results showed that annealing process, after the synthesis of stabilized nanostructures by organometallic method, did not affect the particle size (4.27 ± 1.14 to 4.62 ± 1.59 nm) and dispersion (25.75–27.07%) of the alloyed nanostructures. The modification of Pd electronic features with low Ni amount facilitates the adsorption of the hydrogen on the bimetallic active surface of the catalysts. The PdNi alloys, especially Pd₇₀Ni₃₀/C, tend to display the overpotential of HER to more positive values in comparison with Pd/C catalysts. This behavior is clearly correlated with an improvement by the synergistic effect between the components, which in turn enhance the electrochemical surface area (ECSA) and the real area. Either the hydrogen adsorption resistance and charge transfer resistance are dependent of the Ni amount, due to Ni influences ion/atom recombination or hydrogen desorption.