Unusual, hierarchically structured composite of sugarcane pulp bagasse biochar loaded with Cu/Ni bimetallic nanoparticles

Valorization of agro-wastes into high performance functional materials is a topic that is receiving growing interest. Agro-wastes could be converted into biochar by slow pyrolysis and could be even given high added value by in situ deposition of nanoparticles. Herein, we investigate for the first time the impregnation of copper and nickel nitrates on sugarcane pulp bagasse powder and its slow pyrolysis at 500 °C. The process permitted to obtain unusual hierarchically structured porous biochar material with 40 nm-sized immobilized bimetallic copper-nickel alloy nanoparticles. The materials were characterized by XRD, XPS, Raman spectroscopy, TGA and SEM. As the pure biochar does not exhibits any highly porous structure, it is suggested that copper and nickel salts, or the metallic nanoparticles, are responsible for the fishing net-like structure obtained for the underlying biochar. The alloyed metal nanoparticles are extremely well dispersed over the biochar, with narrow size distribution (403 nm). This work clearly demonstrates that sugarcane pulp bagasse has a particular behavior and could provide highly porous biochar, in one step, for catalytic and other applications where high porosity and surface area are required. More importantly, such a porosity does not require any harsh acidic or basic treatment, and only the catalyst precursors are required.