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 TiO2 and new biochar-based supports (biochar obtained by pyrolysis of miscanthus straw pellets (MSP) and soft wood pellets (SWP) at 550 and 700 degrees 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 (TiO2/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 (similar to 90%) in selective oxidation of methanol to methyl formate in flow gas phase, high selectivity to methyl formate (similar to 80%), and high yield of methyl formate (similar to 88%) after 240 min of illumination. It can be noticed that when TiO2 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.