The influence of experimental parameters on the structure, morphology and electrochemical behavior of Pd-P thin films prepared by electroless deposition

Pd-P thin films over carbon steel were prepared by electroless deposition, using sodium hypophosphite as reducing agent. The influence of the plating conditions, on the properties of the coatings is investigated in detail. The deposits morphology was assessed by Scanning Electron Microscope and Atomic Force Microscopy imaging, their compositions and respective elements distribution determined by Energy Dispersive X-ray Spectrometry and structural information obtained by X-ray diffraction. It has been observed that the amount of co-deposited P depends on both the deposition time and the employed NaH2PO2 concentration, which in turn dictates the degree of amorphicity of the so-prepared Pd-P layers. The modified electrodes electrochemical behaviour, evaluated by cyclic voltammetry in alkaline media, revealed that the hydrogen adsorption/absorption process and the hydrogen evolution reaction are enhanced on alloys with phosphorus content below 10 at.%.