Rational design of single tungsten/cobalt atom oxide anchored on the TiO2-rGO: A highly efficient electrocatalyst for water splitting and photocatalyst for decomposition of pharmaceutical pollutant

Abstract

Single metal atom oxide catalysts (SMAOs) have impressive catalytic efficiency because they maximize the use of atoms, and their unique electronic structures in the reactions. We developed a single tungsten/cobalt atom oxide anchored on the TiO2-rGO catalyst (TPWCoR) from TiO2 P25-rGO and heteropoly acid with tungsten and cobalt. Electron microscope characterization showed that a significant amount of single tungsten/cobalt atom oxide (ST/CAO) was uniformly deposited on TiO2 P25 nanoparticle. The transition metal atoms are equally spread throughout on TiO2 P25-rGO material, according to aberration corrected high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM). The hydrogen evolution reactions and oxygen evolution reactions (HER/OER) are crucial for electrochemical water splitting, and the TPWCoR nanocatalyst is extremely active and stable for these processes. The TPWCoR possessing a higher number of active sites, offers current densities of 10 mA cm−2 at 144 mV for HER and 10 mA cm−2 at 366 mV for OER in alkaline medium with a Tafel slope of 114.2 mV dec−1 (HER) and 62.6 mV dec−1 (OER), respectively. Superior cycling ability was also obtained throughout the alkaline HER and OER processes, showing its potential for use in real-world scenarios in the future. The simple synthetic strategy for producing efficient ST/CAO based HER and OER electrocatalysts for electrochemical water splitting presents a cost-effective approach. Additionally, the prepared TPWCoR nanocatalyst achieves around 96.87 % ciprofloxacin (CF) photodegradation after 60 min of UV irradiation. Analytical definitions of the best catalyst photodegradation processes may be made as variables of catalysts, dosage, and pH of the reaction media. All of these discoveries reveal novel understanding of how to construct low cost, reusable electro-photocatalysts with high water splitting and photodegradation efficiency.