Construction of single tungsten/copper atom oxide supported on the surface of TiO2 for the higher activity of electrocatalytic water splitting and photodegradation of organic pollutant

Abstract

Intense studies are being carried out on single atom catalysts that exhibit remarkable activity and selectivity. To enhance their catalytic abilities, one must have a thorough understanding of the properties of the single metal atom active site and its dynamics in the working state. Herein, we report single metal atom oxide (SMAO) (metal: W/Cu) anchored on TiO2-rGO nanomaterials (SMAO-ED-TiO2-rGO) by simple sonication process. It is efficient for the electrocatalytic hydrogen evolution reaction (HER), oxygen evolution reaction (OER) and photocatalytic degradation of pharmaceutical pollutant. The uniform dispersion of the tungsten/copper metal atom oxide over a TiO2-rGO materials is detected by high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM). The SMAO-ED-TiO2-rGO nanocatalyst has shown impressive HER/OER activity with an overpotential of 121/295 mV at (−)10 mA cm−2 current density and the low Tafel slope of 96/60.3 mV dec−1 in 1 M KOH solution. Further, SMAO-ED-TiO2-rGO nanocatalyst was used for the photocatalytic degradation of ciprofloxacin (CF). After 60 min of UV light irradiation, the SMAO-ED-TiO2-rGO nanocatalyst efficiently photodegraded 98.5% of CF while retaining its activity for five cycles. Superoxide radicals (O2•-) are found to be the main reactive species required in the photodegradation of CF, according to scavenger study of the SMAO-ED-TiO2-rGO nanocatalyst for CF degradation.