In this work, biochar-based electrode materials were developed from two abundant agro-waste precursors, orange peels (OPAB) and date seeds (DSAC), with the aim of designing sustainable carbon supports for alkaline water electrolysis applications. The biomasses were chemically activated using KOH and carbonized at selected temperatures to obtain highly disordered carbon frameworks. The most promising sample, DSAC900, was further modified by nickel doping and polyaniline (PANI) coating to generate a hybrid DSAC900@Ni-PANI composite. X-ray diffraction (XRD) analysis of DSAC900@Ni-PANI confirmed the coexistence of an amorphous carbon matrix, nanostructured NiO phases, and an amorphous PANI layer. The electrochemical behavior of the modified biochars was investigated by cyclic voltammetry (CV) in alkaline medium. Ni- and Mn-doped DSAC900 and OPAB materials exhibited enhanced faradaic responses compared to the undoped biochars, due to the redox activity of the metal oxides. The introduction of PANI further increased the capacitive and pseudocapacitive currents, reflecting improved charge transport and a larger electrochemically active surface. Among the tested materials, DSAC900-based composites, especially DSAC900@Ni-PANI, showed the most pronounced electrochemical response. The combined XRD and CV results highlight a clear structure–electrochemistry correlation and demonstrate that agro-waste-derived biochars functionalized with Ni, Mn and PANI constitute promising platforms for future electrocatalytic hydrogen production studies.
Charafeddine et al. (Tue,) studied this question.