Kinetic Mechanisms Driving Ag+ Reduction and Nanoparticle Synthesis By Atmospheric Pressure Plasma-Driven Solution Electrochemistry
Abstract
Plasma-driven solution electrochemistry (PDSE) is an emerging technique for processing novel materials among other applications. PDSE has a key advantage over conventional electrolysis in that it can inject electrons into solutions without the presence of a metal surface. Current applications of PDSE are limited because of prohibitive energy efficiencies and a lack of understanding in the underpinning processes, including the importance of plasma-injected species relative to solution-generated species and kinetics-limiting effects. Recent studies have shown that there are several factors that differ between PDSE and conventional electrolysis, meaning new and expanded models are required to precisely describe PDSE. For example, it is commonly assumed that reduction processes in PDSE are predominantly mediated by solvated electrons – as is the case in conventional electrolysis – while the influence of ions, photons, and radicals present in the system are considered to be negligible or not studied. However, recent work studying plasma-liquid interactions from ours and other groups have indicated that, while solvated electrons are certainly significant in PDSE reduction processes, they are not wholly deterministic of the plasma-induced solution phase kinetics. The work presented is an investigation of reduction kinetics of Ag+ using a quasi-continuous flow pulsed-DC atmospheric pressure PDSE system. We focus on the evolution of the solution phase from pre- to post-plasma exposure. We present experimental results that, although gathered from indirect characterization techniques, allow us to infer information about the kinetics mediating Ag+ reduction and ensuing nanoparticle nucleation and growth. Specifically, we seek to deconvolve UV-photon induced reactions, neutral hydrogen-driven reduction, and neutral hydroxide-driven processes, in addition to solvated electron-driven reduction. A refined understanding of PDSE in a model system like Ag will enable access to more complex, more efficient, and higher yield chemical processes in PDSE systems that are not possible with conventional electrochemistry.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- May 30, 2021
- Source ID
- 10.1149/ma2021-0122868mtgabs
Entities
People
- Peter J Bruggeman
- Stephen Exarhos
- Yuanfu Yue