Developing nickel phosphide-based nanomaterial as an anode electro-catalyst for the energy and environmental remediation application

K. Demssie
National Taiwan University of science and Technology,
Taiwan

Keywords: nickel phosphide, urea oxidation, current density, energy, environmental pollution

Summary:

Environmental pollution coupled with energy crises becomes one of the biggest problems we are facing today throughout the world. Urea waste is one of environmental pollutant and a simple renewable energy source. Urea decomposition results ammonia to the soil which affects ground water and results soil acidity which in turn reduces soil fertility for agricultural purposes (reduced crop productivity) and also releases NOx compounds to the atmosphere resulting acid rain. As a result, rural communities, in particular, suffered a lot from healthy problems. To address such a problem, electrochemical decomposition of urea in to electricity without emission of environmental pollutant is investigated. However, urea electro-oxidation reaction is a sluggish kinetics due to 6e- transfer process. Therefore, it requires a highly active anode electro-catalyst nanomaterial with high conversion performance. The purpose of this paper is to develop nickel phosphide-based nanomaterial as an anode electro-catalyst to convert urea into electricity without the release of environmental pollutants. A number of nickel phosphide-based materials were synthesized and characterized using XRD, FESEM, FTIR, UV-VIS, TGA, and EDX. The physical characterization shows nanospherical nickel phosphide with a particle size of 2.4 nm, molecular interaction, and multifaceted crystal phase. After physical characterization, the electro-catalytic performance of the proposed material was tested using a cyclic voltammeter. Among synthesized materials, PdNiP@PEDOT:PSS/rGO shows outstanding urea conversion performance with a low onset potential of 0.32 V vs SCE to deliver a maximum current density of 149 mAcm-2. This is due to the higher electrochemically active surface area of 3.28 cm-2, high kinetics, and durability of the as-synthesized material. Therefore, the developed nanomaterial is a promising candidate as an anode electro-catalyst material for the conversion of urea waste into electricity to minimize energy crises and environmental problems.