Enhanced Photocatalytic Hydrogen Production from Glucose Aqueous Solution Using Nickel Supported on LaFeO3

Abstract

Nowadays one of the topics of greatest interest to the scientific community is the search for new eco-friendly technologies that allow the production of energy. In particular, one of the main players in this area is hydrogen. Several innovative processes are proposed in the literature for the production of hydrogen. One of these is the heterogeneous photocatalysis. Furthermore, it is also interesting to evaluate the source from which hydrogen is obtained. An interesting solution is glucose, one of the most familiar biomass, which can be used to produce hydrogen from a photocatalytic process. For this reason, in this work we propose the use of Ni as active phase supported on LaFeO3 photocatalyst for the renewable H2 production from glucose aqueous solution. Perovskite photocatalysts are quite encouraging materials for H2 production from aqueous solution owing to their stability in water. Low-cost nickel can be used to improve the performance of perovskites, modifing their surface and thus avoiding the use of expensive noble metal based cocatalysts. Specifically, the LaFeO3 catalyst was prepared by solution combustion synthesis using citric acid as organic fuel. A specific amount of Ni was deposited on LaFeO3 surface by chemical reduction method, using sodium borohydride (NaBH4) as a reducing agent. The prepared samples were characterized by different techniques, such as XRD and UV-Vis. The photocatalytic tests were carried out in a pyrex cylindrical reactor equipped with a N2 distributor device and irradiated by four UV lamps (emitting at 365 nm) positioned at the same distance from the external surface of the reactor (about 30 mm). The tests were realized with a solution volume equal to 80 ml, an initial concentration of glucose equal to 5550 µmol L-1 and a catalyst dosage equal to 1.5 g L-1. The experimental results evidenced that the presence of Ni on LaFeO3 surface enhanced the H2 production and in particular the highest hydrogen production (about 2242 µmol L-1 after 4 h of irradiation time) was obtained with Ni/LaFeO3, whereas the raw LaFeO3 was able to produce a lower H2 amount (about 1394 µmol L-1 after the same irradiation time).