Using site occupation disorder to build bulk structures of Ni1-xAlx

  • C J Thesner North West University
  • A Falch North West University
  • C G C E van Sittert North West University
Keywords: Site Occupation Disorder, General Utility Lattice Program, nickel, aluminium, bimetallic phases, Raney nickel

Abstract

Raney nickel shows potential as an electrocatalyst for the oxygen evolution reaction (OER). However, the catalytic activity of Raney nickel varies with its properties. These properties are related to the composition of the bimetallic precursor used to synthesise Raney nickel. The bimetallic precursor consists of a combination of bimetallic phases. Various studies have been done on the well-known bimetallic phases, namely, Ni2Al3, NiAl and NiAl3. However, to get a more comprehensive understanding of the influence of the bimetallic precursor on the properties of Raney nickel, a larger spectrum of bimetallic phases needs to be evaluated. In this study, the Site Occupation Disorder (SOD) program was used to build solid-state structures (bimetallic phases) with various Ni1-xAlx bimetallic ratios. These Ni1-xAlx bimetallic phases were evaluated, and unique configurations for each Ni1-xAlx bimetallic ratio were obtained. The unique configurations were geometrically optimised using the General Utility Lattice Program (GULP) at 0K. These optimised unique configurations were thermodynamically evaluated over a range of 0.1K – 1200K, and the most stable configurations with a probability higher than 10% were identified. This study found that the stable non-homogeneous configurations fall within a range of 20% - 80% Ni content. A weight average combination of these configurations of the bimetallic phases will produce a non-homogeneous precursor with an average Ni content of 20% - 80%, which is in close agreement with experimental results. The approach in this study enables researchers to obtain a larger, repeatable spectrum of bimetallic phases for the investigation of Raney nickel precursors.

Author Biographies

C J Thesner, North West University

Applied Molecular Modelling Group, Research Focus Area: Chemical Resource Beneficiation (CRB), North-West University, Private Bag X6001, Potchefstroom 2520, South Africa

A Falch, North West University

Electrochemistry for Energy & Environment Group, Research Focus Area: Chemical Resource Beneficiation (CRB), North-West University, Private Bag X6001, Potchefstroom 2520, South Africa

C G C E van Sittert, North West University

Applied Molecular Modelling Group, Research Focus Area: Chemical Resource Beneficiation (CRB), North-West University, Private Bag X6001, Potchefstroom 2520, South Africa

Published
2022-01-25
How to Cite
Thesner, C., Falch, A., & van Sittert, C. G. (2022). Using site occupation disorder to build bulk structures of Ni1-xAlx. Suid-Afrikaans Tydskrif Vir Natuurwetenskap En Tegnologie / <i>South African Journal of Science and Technology</I&gt;, 40(1), 174-179. Retrieved from http://satnt.co.za/index.php/satnt/article/view/900
Section
Conference of the South African Advanced Materials Initiative