Synthesis of NiMoO₄ ceramics by proteic sol-gel method and investigation of their catalytic properties in hydrogen production

A proteic sol-gel route was used in the production of NiMoO4 catalysts, which used edible gelatin as a precursor. The triple helix structure of a protein in contact with identical structures acquires an unfolded form, which favors the interaction of the reactive groups of the gelatin (NH3+ and COO-) with the metallic ions (MoO42- and Ni2+). The synthesized catalysts were thoroughly characterized using techniques such as X-ray diffraction, thermo-gravimetric and differential thermal analysis, Raman scattering, scanning and transmission electron microscopies, UV-Vis spectroscopy, and colorimetry. The results showed that it is possible to prepare the phase-pure alpha-NiMoO4 polymorph only at temperatures above 700 degrees C, while a mixture of the polymorphs a and 1 were obtained at lower temperatures. The synthesized materials calcined at 300, 500, and 700 degrees C have their catalytic potentials tested in the ethanol steam reforming reaction aiming the production of hydrogen and presented a good performance. The results indicated that among tested materials, the sample calcined at 700 degrees C exhibited the highest stability, activity, and best selectivity relative to the product of interest.