Temperature-Controlled Synthesis of Fe-Based Graphite Nanocomposites for Sustainable Photocatalysis and Electrocatalysis Application

Abstract

This study reports the temperature-controlled synthesis of iron-based graphite nanocomposites prepared via a sol–gel route followed by electro-spraying and evaluates their photocatalytic and electrocatalytic performance. At a calcination temperature of 750°C, the material consisted mainly of hematite (α-Fe₂O₃) nanoparticles dispersed in an amorphous carbon matrix. Owing to its semiconducting nature and low conductivity, this sample exhibited limited photocatalytic activity toward methylene blue degradation and weak electrocatalytic behavior for glycerol, methanol, and urea oxidation. Increasing the synthesis temperature to 850°C induced carbothermal reduction of Fe₂O₃, yielding zero-valent iron (Fe⁰) nanoparticles embedded in a semi-graphitized carbon framework. This Fe⁰-rich composite showed significantly enhanced photocatalytic hydrogen evolution, particularly at higher methanol concentrations, and superior electrocatalytic performance with higher current densities and lower onset potentials. The improved activity is attributed to enhanced electrical conductivity, abundant active metallic sites, and synergistic effect between Fe⁰ and graphitic carbon, offering clear advantages over conventional Ni-based electrocatalysts.