Designed of bifunctional Z-scheme CuSnO3@Cu2O heterojunctions film for photoelectrochemical catalytic reduction and ultrasensitive sensing nitrobenzene

A direct Z-scheme CuSnO 3 @Cu 2 O heterojunctions photo-electroactive material were reasonably designed and fabricated by electrodeposited Cu 2 O on fluoride doped tin oxide (FTO) substrate followed anchoring 3D CuSnO 3 microspheres onto Cu 2 O film. The novel 3D architectures can favor the mass transfer, provide multiple active sites and improve light absorption during the photoelectrocatalytic reactions. The artificial heterogeneous Z-scheme photoelectrochemical (PEC) system further prolong electrons path, promote the separation of photogenerated charge carriers and maintain high redox ability. As expected, the constructed Z-scheme CuSnO 3 @Cu 2 O as the photocathode show excellent dual functional properties which can not only detect the trace nitrobenzene (NB) but also undergo catalytic reduction of NB to less toxic species (aniline, AN) under visible light irradiation. Based on CuSnO 3 @Cu 2 O photocathode, the photocurrent was linearly proportional to the concentration of NB ranging from 0.5 nmol L −1 to 100 μmol L −1 , and the detection limit (S/N = 3) was 0.43 nmol L −1 . The fabricated sensor was successfully used to sensing the trace NB in real samples and it showed excellent anti-interference ability, good reproducibility and high stability. Besides, CuSnO 3 @Cu 2 O exhibited high PEC activity for NB reduction, 85.70% reduction efficiency was achieved within irradiation for 2.5 h. Thus, this study may provide insights into designing advanced photoeletrocatalysts for energy conversion and render a tunable platform in photoelectrochemistry for the monitor and clean-ups of environmental pollutants.