UCoO₄/Co₃O₄ Heterojunction as a Low-Cost and Efficient Electrocatalyst for Oxygen Evolution

Abstract

The development of actinide materials has provided new strategies for the utilization of nuclear waste, such as depleted uranium, a mildly radioactive waste in the nuclear power industry, which could be a precious resource for many fields, especially water splitting. The catalytic performance of water splitting is limited by the slow kinetics of the oxygen evolution reaction (OER), and it is extremely challenging to design efficient OER catalysts that are highly stable and inexpensive. Here, we design and describe a series of U5–35% -Co3O4 electrocatalysts, which were synthesized using uranyl nitrate as a precursor via a simple and scalable method. Interestingly, when the U/Co molar ratio was 20%, a UCoO4/Co3O4 heterojunction formed with high catalytic efficiency and excellent long-term electrolytic stability. The UCoO4/Co3O4 heterojunction catalyst shows a lower overpotential (280 mV) at a current density of 10 mA cm–2, and the slope of Tafel is 43.8 mV decade–1 in a 0.1 M KOH alkaline solution. Soft X-ray absorption spectroscopy shows that the cooperative effect of UCoO4 and Co3O4 can improve the electrochemical activity of the material. This study produced an active U/Co-based catalyst for OER, which provides a simple, scalable, low-cost, and highly efficient catalyst for overall water splitting.

Rational Construction of a Triple-Phase Reaction Zone Using CuO-Based Heterostructure Nanoarrays for Enhanced Water Oxidation Reaction

“…The urgent demand to address the fossil fuel crisis and mitigate the environmental degradation has prompted a global push to advance cutting-edge technologies for storing solar power and producing sustainable clean energy. , The oxygen evolution reaction (OER), a complicated four-electron-participated process with sluggish reactive kinetics, has been regarded as a fundamental bottleneck in rising carbon-neutral energy technologies such as water splitting and Zn–air batteries. , Although RuO 2 and IrO 2 are highly active materials for the OER, their high price and unsatisfactory durability have restricted their utilization on a large scale . Therefore, it is significant to develop alternative earth-abundant transition-metal electrocatalysts that are cost-effective, having remarkable OER activity and stability, including Co-, Mn-, Cu-, and Ni-related oxides because of their inherently regulable geometric and electronic properties, and environmental friendliness. − …”

“…To further boost OER performance for transition-metal oxides (TMOs), many researchers offered a variety of tactics (such as interface engineering, defect, dopant, or single-atom design) to enhance the intrinsic activity of catalytic sites through optimizing the adsorption free energy of key intermediates to expedite the rate-determined step in the entire reactions. − Additionally, the increased specific surface area in electrocatalysts may also add the density of electrocatalytic active sites, i.e. porous nanostructures .…”