Magnetic-phototactic microbial robots for enhanced directional photocatalysis and directional recovery of photocatalyst

Photocatalytic reactions, such as H 2 production, CO 2 reduction, wastewater treatment, have emerged as highly promising technological solutions for addressing energy and environmental challenges. However, sedimentation-induced low photocatalytic activity and inconvenient recycling limit their practical applications. Here, we have developed magnetic-phototactic microbial robots for enhancing photocatalysis effect and directional recycling used/inactive photocatalyst. We first synthesized a magnetic g-C 3 N 4 /Fe 3 O 4 photocatalyst with enhanced visible light absorption, and then functionalized positively phototropic microalgae with the magnetic composite, which is denoted as magnetic-phototactic microbial robots. The photocatalytic efficiency of magnetic-phototactic microbial robots has substantially augmented up to 320% than that of g-C 3 N 4 /Fe 3 O 4 . Moreover, the magnetic-phototactic microbial robots can autonomously carry catalysts to bright underwater environment to efficiently utilize solar light for photodegradation, as well as exhibit highly efficient targeted recovery and recyclability. The highly efficient, environmentally friendly, and recyclable magnetic-phototactic microbial robot is expected to make great impacts on energy and environment fields.