Highly active Zn-doped cobalt ferrite catalysts for photocatalytic and electrocatalytic hydrogen production

Abstract

Hydrogen production from sustainable resources could hold the key to solving the current environmental concerns. To further advance in this area, in our work, we focus on the production of green and sustainable hydrogen through water splitting using photocatalysis and electrocatalysis. The processes are being performed using Zn-substituted cobalt ferrite, fabricated via the sol–gel auto-combustion process (SGC). The structural traits are analysed through XRD and Rietveld refinement studies. Spherical-shaped grains, having an approximate size of 70.88 and 71.61 nm, are observed for the CZ1 and CZ3 spinel nanoferrites. With the Zn doping, an uneven trend has been observed for the band gap varying from 2.07 to 1.73 eV, whereas the specific surface area goes on to increase from 6.418 to 8.566 m2/g. This will result in the enhancement of photo/electrocatalytic properties of developed nanocatalysts. Thus, the CZ3 catalyst shows the highest photocatalytic H2 yield of 15 mmol gcat-1, having a Tafel slope of 99.75 mV/dec. Therefore, with excellent photo/electro-catalytic properties, the pristine and Zn-substituted cobalt nano catalysts can be suitable candidates for the green H2 energy generation. The work indicates the potential of cost-effective spinel ferrites as catalysts for hydrogen production.