Pulsed Laser Deposition of Co-nanoparticles embedded on B-thin film: A very efficient catalyst produced in a single-step process

摘要

Advances in "Nanotechnology" may open the.way to replace expensive traditional noble-metal with cheaper new catalyst entries without losing efficiency. Here we show that Pulsed Laser Deposition of Co-nanoparticles partially embedded into B-thin film catalyst is a step towards this direction. Depending on the energy density, the laser process is able to produce well-dispersed spherical Co nanoparticles, with average size of 11-15 nm, partially embedded within B-based film matrix in a single-step deposition. This novel catalyst film exhibits catalytic activity comparable to that observed with commercial Pt/carbon black catalyst and significantly better than that with Pd/carbon black powder for hydrogen production by hydrolysis of chemical hydrides. Availability of a large number of under-coordinated active atoms owing to the size and shape of Co nanoparticles, polycrystalline nature of nanoparticles with linear defects in form of grain boundaries, and optimum interaction with reactant provided by electron enrichment from B, are the main features acquired by the Co nanoparticles that exhibit high catalytic efficiency. Boron plays a crucial role in avoiding coarsening of Co nanoparticles during both the reaction course and the heat treatment while offering, at same time, high tolerance against deactivation and oxidation by electron transfer to Co.