TY - JOUR
T1 - Thermodynamic evaluation of trace-amount transition-metal-ion doping in NiOOH films
AU - Tkalych, Alexander J.
AU - Martirez, John Mark P.
AU - Carter, Emily Ann
N1 - Funding Information:
We are grateful to the Air Force Office of Scientific Research for funding (grant No. FA9550-14-1-0254). We acknowledge use of the TIGRESS high performance computer center at Princeton University. We also acknowledge the High Performance Computing Modernization Program of the US Department of Defense for providing additional computational resources. We thank Ms. Nari Baughman and Dr. Johannes M. Dieterich for critical reading of this manuscript.
Funding Information:
We are grateful to the Air Force Office of Scientific Research for funding (grant No. FA9550-14-1-0254). We acknowledge use of the TIGRESS high performance computer center at Princeton University. We also acknowledge the High Performance Computing Modernization Program of the US Department of Defense for providing addi- tional computational resources. We thank Ms. Nari Baughman and Dr. Johannes M. Dieterich for critical reading of this manuscript.
PY - 2018
Y1 - 2018
N2 - In aqueous solution, NiOOH has a strong tendency to spontaneously incorporate various transition-metal ions. These impurities dramatically affect the properties of NiOOH and may have been present unknowingly in NiOOH systems throughout the past several decades. A better understanding of this tendency of NiOOH to spontaneously incorporate possible contaminants therefore is of great interest. In this work, we calculated the free energies of adsorption and incorporation of Fe3+, Co3+, and Mn4+ dopants in β-NiOOH using ab initio thermodynamics. We define the aqueous phase energies for these dopants using both calculated solid phase bulk energies and their corresponding experimental solubilities. We then demonstrate that only a weak driving force exists for adsorption of Fe3+ and Co3+ complexes on the surface of β-NiOOH and no tendency at all for the adsorption of Mn4+ aquo and hydroxo complexes. We predict a strong thermodynamic driving force for bulk incorporation of Fe3+ and Co3+, even at trace concentrations (ppb to ppm levels) under ambient and basic aqueous conditions, but no such tendency for Mn4+. These results provide a thermodynamic explanation for the scavenging and doping behavior of NiOOH observed experimentally and highlight the importance of careful control of the experimental conditions when studying this material.
AB - In aqueous solution, NiOOH has a strong tendency to spontaneously incorporate various transition-metal ions. These impurities dramatically affect the properties of NiOOH and may have been present unknowingly in NiOOH systems throughout the past several decades. A better understanding of this tendency of NiOOH to spontaneously incorporate possible contaminants therefore is of great interest. In this work, we calculated the free energies of adsorption and incorporation of Fe3+, Co3+, and Mn4+ dopants in β-NiOOH using ab initio thermodynamics. We define the aqueous phase energies for these dopants using both calculated solid phase bulk energies and their corresponding experimental solubilities. We then demonstrate that only a weak driving force exists for adsorption of Fe3+ and Co3+ complexes on the surface of β-NiOOH and no tendency at all for the adsorption of Mn4+ aquo and hydroxo complexes. We predict a strong thermodynamic driving force for bulk incorporation of Fe3+ and Co3+, even at trace concentrations (ppb to ppm levels) under ambient and basic aqueous conditions, but no such tendency for Mn4+. These results provide a thermodynamic explanation for the scavenging and doping behavior of NiOOH observed experimentally and highlight the importance of careful control of the experimental conditions when studying this material.
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U2 - 10.1149/2.0101811jes
DO - 10.1149/2.0101811jes
M3 - Article
AN - SCOPUS:85067408313
SN - 0013-4651
VL - 165
SP - F907-F913
JO - Journal of the Electrochemical Society
JF - Journal of the Electrochemical Society
IS - 11
ER -