Cl-doped CuO for electrochemical hydrogen evolution reaction and tetracycline photocatalytic degradation

Photocatalysts play a vital role in energy conversion technologies and wastewater treatment. Catalyst's electronic structure can be tuned by a simple anion doping strategy to enhance the catalytic properties. In this work, different atomic percentages of Cl‾ doped into CuO lattices were synthesized using deep eutectic solvent (DES) by increasing the molar ratio of choline chloride to urea. Here, DES act as a green solvent and, Cl‾ source in preparing catalysts. Further, catalysts' crystallinity and surface properties were analyzed through X-ray diffractometer and transmission electron microscopy. X-ray photoelectron spectroscopy confirms the presence of Cl‾ dopant in CuO lattices. Synthesized catalysts were studied for electrochemical hydrogen evolution reaction (HER) and tetracycline photocatalytic degradation. Among the synthesized electrocatalysts, 2.48 at% of Cl-doped CuO catalyst displays optimum HER activity in 1 M H2SO4 electrolyte with an overpotential of 400 mV at the current density of 10 mA cm−2 and a Tafel value of 89 mV dec−1. Moreover, the same catalyst shows 83.5% degradation of tetracycline in 240 min under the illumination of a 35 W Xe arc lamp. This work provides a simple strategy to develop a catalyst with Cl‾ doping into CuO crystal structure by DESs and enhance its HER and wastewater treatment activity.