Efficient Electrochemical Water Oxidation and Oxidative Degradation of Rhodamine B: A Comparative Study Using High-Purity Birnessites Containing Li+, Na+ or K+ Ions

High-purity birnessites, containing Na+, K+ or Li+ in the interlayer were prepared respectively with complexing agent EDTA at room temperature. The structural features and chemical compositions were characterized by X-ray diffraction, thermogravimetric analysis, Fourier transform infrared spectroscopy, Brunauer-Emmett-Teller analysis and field emission scanning electron microscopy. The electrocatalytic properties of these materials against oxygen evolution reaction (OER) in alkaline media were studied. Cyclic voltammetry and linear sweep voltammetry curves showed that Li-Bir had the highest water oxidation activity. Meanwhile, Li-Bir performed stably for 4000 s. For birnessites containing different alkali metals (K+, Na+ or Li+), the organic dye rhodamine B degradation rates were significantly different in acidic media. At pH 1, the degradation rate of Li-Bir was obviously higher than those of K-Bir and Na-Bir. The surface area of Li-Bir (107.282 cm(2) g(-1)) is much larger than those of Na-Bir (35.623) and K-Bir (11.900), indicating that specific surface area was one of the main factors affecting the OER activity and degradation efficiency of birnessite.