Gadolinium doped CeO2 for efficient oxygen and hydrogen evolution reaction

Abstract

Hydrogen evolution reaction (HER) is a significant half reaction in water splitting and it is spirit of energy storage and conversion applications. Recently, high durability and catalytic activity of effective electrodes are necessary to enlarge clean and sustainable energy sources. However, overcoming the overpotential and to improve HER and OER performance is still one of the complicated tasks. Hence, in this present work, gadolinium (Gd) doped cerium oxide (CeO2) was successfully synthesized through a facile co-precipitation method. High intense peak at 28.5° clearly indicated CeO2 cubic structure formation identified by using X-Ray diffraction. The optical phonon mode of F2g and oxygen vacancies mode was detected by using Raman spectra. The optical properties of CeO2 were detected with help of photoluminescence spectroscopy (PL). Fourier-transform infrared (FTIR) spectroscopy confirmed Ce-O vibration of CeO2 crystal existence. Surface morphology of CeO2 was thoroughly studied by using SEM images. HER and OER activity of pristine and Gd doped CeO2 was thoroughly investigated with the help of linear sweep voltammetry. Compared to pristine CeO2, high content of Gd doped CeO2 exhibited excellent HER and OER activity with low overpotential (99 mV for HER and 369 mV for OER) and small Tafel slope (211 mV/dec for HER and 183 mV/dec for OER). Addition of rare earth metal influenced the structural and catalytic properties of optimized metal oxide. Hence, the incorporation of Gadolinium in CeO2 plays a crucial role to enhance both HER and OER performance and it is one of the good candidates for energy conversion applications.