One-step synthesis of N-doped metal/biochar composite using NH 3 -ambiance pyrolysis for efficient degradation and mineralization of Methylene Blue.

A series of new biochar-supported composite based on the combination of biochar and metallic nanoparticles (NPs) were produced through single-step pyrolysis of FeCl3 -Ti(OBu)4 laden agar biomass under NH3 environment. The physiochemical properties of composites were characterized thoroughly. It has found that heating temperature and N-doping through NH3 -ambiance pyrolysis significantly influence the visible-light sensitivity and bandgap energy of composites. The catalytic activities of composites were measured by degradation of Methylene Blue (MB) in the presence or absence of H2 O2 and visible-light irradiation. Our best catalyst (N-TiO2 -Fe3 O4 -biochar) exhibits rapid and high MB removal competency (99.99%) via synergism of adsorption, photodegradation, and Fenton-like reaction. Continuous production of O2 - and OH radicles performs MB degradation and mineralization, confirmed by scavenging experiments and degradation product analysis. The local trap state Ti3+ , Fe3 O4 , and N-carbon of the catalyst acted as active sites. It has suggested that the Ti3+ and N-doped dense carbon layer improve charge separation and shuttle that prolonged photo-Fenton like reaction. Moreover, the catalyst is highly stable, collectible, and recyclable up to 5 cycles with high MB degradation efficiency. This work provides a new insight into the synthesis of highly visible-light sensitized biochar-supported photocatalyst through NH3 -ambiance pyrolysis of NPs-laden biomass.