Comparative study of toluene oxidation over reduced graphene oxide-supported Pt and Ni catalysts

Reduced graphene oxide (rGO) was prepared from graphite by modified Hummers oxidation followed by two-step thermal reduction and used as support for Pt and Ni catalysts in toluene oxidation. The protocol produced few-layer rGO with residual oxygenated anchoring groups and with a 23-fold increase in Brunauer-Emmett-Teller (BET) surface area. Pt/rGO (1 wt% Pt) and Ni/rGO (10 wt% Ni) were obtained by wet impregnation. XRD, Raman, FTIR, BET, SEM-EDS, TGA and H 2 -TPR linked structure, dispersion and reducibility to catalytic behavior. Scherrer analysis gave apparent coherent-domain sizes of 9.4 nm for Pt 0 (111) and 9.3 nm for Ni 0 (200). Pt/rGO reached T 50 ≈ 255 °C and 99% conversion at 400 °C, whereas Ni/rGO reached 55% at 400 °C. Time-on-stream tests confirmed stable operation and CO 2 as the only carbon-containing product detected. The results demonstrate that rGO can serve as a practical carbon support for noble and non-noble metal formulations in VOC oxidation, while emphasizing the central role of metal reducibility, dispersion and metal-support interaction.