Bifunctional nest-like self-floating microreactor for enhanced photothermal catalysis and biocatalysis

Abstract

As a bifunctional nest-like self-floating microreactor, Ag-decorated single crystal black TiO₂ nanosheets supported on macroporous polyurethane foam (PUF) with a microbial culture are fabricated via hydrothermal and photodeposition methods combined with an in situ NaBH₄ reduction strategy. Photocatalysis and photothermal catalysis reactions occur on the surface; meanwhile, biocatalysis occurs inside the PUF composites. “Bifunctional” refers to a composite that can act as a microreactor that possesses the functions of photocatalysis for degradation of organic contaminants and biocatalysis for microbial degradation. The bifunctional nest-like microreactor floats on the surface of water due to the support of the PUF, which is favorable for using solar light and recycling catalysts. The bifunctional nest-like self-floating microreactor exhibits prominent photocatalytic and biocatalytic performances for the degradation of cephalosporin (96.1%) at low temperature under solar light irradiation that are ∼1.8-fold and 1.2-fold higher than those of single biocatalysis and photocatalysis, respectively. This high activity can be attributed to the synergy of photocatalysis on the outer surface and biocatalysis on the inner surface of the microreactor. After 6 cycles, the activity is nearly constant, indicating that this microreactor is highly stable, which is favourable for practical applications in the field of low-temperature antibiotic wastewater remediation.