Dual Functionality of TiO₂/Biochar Hybrid Materials: Photocatalytic Phenol Degradation in the Liquid Phase and Selective Oxidation of Methanol in the Gas Phase

A series of new inorganic–organic hybrid materials based on TiO 2 and new biochar-based supports (biochar obtained by pyrolysis of miscanthus straw pellets (MSP) and soft wood pellets (SWP) at 550 and 700 °C) were successfully prepared using ultrasound-assisted methodology. The resulting composites were characterized by a wide range physicochemical techniques and investigated in water and gas-phase photocatalytic test reactions. Our best composite (TiO 2 /SWP700) achieved phenol degradation of 64.1% (under UV light) and 33.6% (under visible light). In addition, it also showed an extraordinarily high activity (∼90%) in selective oxidation of methanol to methyl formate in flow gas phase, high selectivity to methyl formate (∼80%), and high yield of methyl formate (∼88%) after 240 min of illumination. It can be noticed that when TiO 2 is supported on biochar it presented a superior photocatalytic ability and could be recycled at least 5 times in both photocatalytic runs tests with reproducible high photocatalytic efficiency.