In situ ATR–FTIR spectroscopy on Ni–P alloy electrodes

Abstract

In situ ATR–FTIR spectroscopy has been extended to the study of CO and pyridine adsorptions at crystalline and amorphous Ni–P alloy film electrodes, with an emphasis on the alloying effect of P on their adsorption configurations on Ni sites. The Ni–P films were prepared with initial seeding of a catalytic Pd layer on Si, followed by chemical deposition. Transition from bridge-bonded CO (CO B) dominant to linearly bonded CO (CO L) dominant adsorption was found with increasing P content, together with a blue-shift in the CO L vibrational frequency and an attenuation of the Stark tuning rate of CO L. As for Py on Ni–P electrodes, essentially the N-end-on adsorption was revealed, in contrast to the edge-tilted adsorption on Ni electrode. Modification in the adsorption configurations as compared to that on Ni electrode is ascribed mainly to the site-blocking effect with alloying P, rather than to partial electron transfer between Ni and P.