Mono- and bimetallic pd-pt nanoparticles as an efficient tool for the intensification of transcrystalline hydrogen transport

Abstract

A technique has been developed for obtaining highly active Pd-Pt nanocatalysts on the surface of all-metal Pd-23%Ag membranes. These coatings were a large number of pentagonally structured Pd-Pt nanoparticles with an average size of about 100 nm, designed to intensify the process of hydrogen transport. By melting and rolling with intermediate annealing, palladium-silver foils 30 µm thick were obtained, which acted as the basis of the membranes. Surface modification was carried out by electrolytic deposition with a change in the parameters of the deposition current and the composition of the working solution. Classical methods made it possible to obtain spherical particles on the surface of thin palladium-silver films. However, a decrease in the deposition current density, compared to classical methods, and a clear ratio of components in the working solution with the addition of a surfactant made it possible to obtain coatings based on particles with a special geometry. The developed materials were studied in the processes of low-temperature (25 °C) hydrogen transport as diffusion membrane filters, where they demonstrated penetrating flux density values up to 0.42 mmol/s m² at operating pressures up to 0.3 MPa. It has been established that the density values of the hydrogen penetrating flux through membranes modified with pentatwinned Pd-Pt particles are up to 2.1 times higher than through membranes with classical palladium black. These nanocatalysts based on pentatwinned Pd-Pt particles made it possible to significantly intensify hydrogen transport at low temperatures. The developed membrane materials can become the basis for both low-temperature devices, such as a fuel cell, a hydrogen compressor, and find application as diffusion filters in steam reforming reactors.