Inductive effects in cobalt-doped nickel hydroxide electronic structure facilitating urea electrooxidation
Stephen W Tatarchuk1, Rachelle M Choueiri2, Xenia V Medvedeva1
1Department of Chemistry and Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, ON, N2L 3G1, Canada.
Chemosphere
|June 17, 2021
Summary
Optimizing nickel-cobalt hydroxide catalysts for urea oxidation reaction (UOR) enhances energy capture from waste. Tuning the Ni:Co ratio controls active sites and intrinsic activity, improving UOR performance and reducing environmental urea emissions.
Area of Science:
- Electrochemistry
- Materials Science
- Environmental Science
Background:
- Electrochemical oxidation of urea (UOR) offers a sustainable method for waste valorization and pollution control.
- The catalytic mechanisms driving high performance in doped nickel catalysts for UOR are not fully understood.
- The specific role of cobalt doping in nickel hydroxide for UOR activity requires further elucidation.
Purpose of the Study:
- To investigate the impact of varying nickel-cobalt ratios on the catalytic activity and active site density for UOR.
- To elucidate the fundamental reasons behind enhanced UOR performance in Ni-Co hydroxide systems.
- To guide the rational design of advanced electrocatalysts for urea oxidation.
Main Methods:
- Synthesis and characterization of nickel-cobalt hydroxide catalysts with controlled Ni:Co ratios.
- Electrochemical testing to evaluate urea oxidation reaction (UOR) performance.
- Density functional theory (DFT) calculations to probe electronic structure and reaction mechanisms.
Main Results:
- Ni90Co10(OH)2 exhibited the highest geometric current density due to increased surface sites.
- Ni20Co80(OH)2 demonstrated maximized intrinsic activity for UOR.
- DFT calculations revealed that cobalt doping modifies Ni 3d electronic states, affecting Ni oxidation energy and adsorbate interactions.
Conclusions:
- Tuning the Ni:Co ratio in hydroxide catalysts is crucial for optimizing both active site availability and intrinsic catalytic activity for UOR.
- Cobalt doping plays a key role in enhancing UOR performance by altering electronic properties and surface interactions.
- This study provides insights into catalyst design for efficient electrochemical urea oxidation, contributing to waste-to-energy applications.
Keywords:
DFTElectrocatalysisElectronic structureNickel-cobalt hydroxideSol-gelUrea oxidation reactionMore Related Videos
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