Utilizing transparent and conductive SnO₂ as electron mediator to enhance the photocatalytic performance of Z-scheme Si-SnO₂-TiO_x

Abstract

• A novel Z-scheme Si-SnO₂-TiO_x with SnO₂ as electron mediator is first constructed.

• Transparent and conductive SnO₂ can pass light through and promote charge transport.

• V_O from SnO₂ and TiO_x improve photoelectrochemical performances.

• Efficient photocatalytic degradations originate from the Z scheme construction.

Z-scheme photocatalysts, with strong redox ability, have a great potential for pollutants degradation. However, it is challenging to construct efficient Z-scheme photocatalysts because of their poor interfacial charge separation. Herein, by employing transparent and conductive SnO₂ as electron mediator to pass light through and promote interfacial charge transportation, a novel Z-scheme photocatalyst Si-SnO₂-TiO_{x (1<x<2)} was constructed. The Z-scheme photocatalyst displayed an order of magnitude higher photocurrent density and a 4-fold increase in open-circuit potential compared to those of Si. Moreover, the onset potential shifted negatively for approximately 2.2 V. Benefiting from these advantages, this Z-scheme Si-SnO₂-TiO_x exhibited efficient photocatalytic performance toward phenol degradation and mineralization. 75% of the phenol was degraded without bias potential and 70% of the TOC was removed during phenol degradation. Other typical pollutants such as bisphenol A and atrazine could also be degraded without bias potential. Introducing a transparent and conductive electron mediator to construct Z-scheme photocatalyst gives a new sight to the improvement of photocatalytic performance in Z scheme.

Graphical abstract

Keywords

Z-scheme photocatalyst / Tin oxide / Electron mediator / Organic pollutant

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