DURIP Spectroscopy Enhanced Analytical (SEA) Suite for Studies of Oxygen and Carbon Dioxide Management in the Undersea Environment
Abstract
The management of oxygen and carbon dioxide are essential to human performance in the undersea environment. The selective generation of breathable oxygen (O2) and recycling of carbon dioxide (CO2) in an undersea environment practically expands the mission and capabilities of the Department of Defense (DoD) and the Office of Naval Research (ONR). Generating O2 and managing CO2 #on-the-fly# engenders more maneuverable underwater and multi-domain operations involving divers. The generation of O2 and the disposal of CO2 are connected reactions. Electrogeneration of O2 from seawater produces four protons and four electrons that can be directed to reduce CO2 to formate, which may dissolve in seawater, thus eliminating the need for a rebreather. Two fundamental knowledge gaps need to be addressed that rely on precise analytical measurements:- pH gradients may form at the electrode#solution interface owing to the inherently unbuffered conditions of seawater; thus, pH and ion concentrations need to be spectroscopically detected and analytically measured for the selective generation O2 and desired products of CO2 reduction.- Speciation of the reduced products of CO2 reduction in aqueous systems must be measured, particularly at the electrode#solution interface, to ensure the selective formation of seawater soluble products. The SEA Instrumentation Suite will allow the research program to address these two knowledge gaps by revealing the details where catalysis occurs, at the electrode-solution interface. Catalytic electrodes will be modified with molecular probes to quantify changes in H+, Cl#, Br# and formate concentrations. Improving catalyst selectivity will rely heavily upon understanding what intermediates are formed during these reactions as well as what these intermediates transform into. Spectroscopy and analytical techniques are also required for understanding the product speciation of electrochemical CO2 reduction, with formate being one of myriad possible products (e.g., methanol, carbon monoxide) of this reaction. For these spectroscopic and analytical measurement to be made,a SEA Instrumentation Suite has been designed that comprises a Cary 5000 UV-Vis-NIR Spectrophotometer for electronic spectroscopic measurements, a Fluoromax Plus-C Fluorimeter to detect luminescence of emissive species on electrode surfaces, Pike Technology VeeMAX III with ATR to record vibrational spectra of electrode surface bound species, an Agilent 5977C Gas Chromatography (GC)-Mass Spectrometry Detector (MSD) to analyze products of catalytic reactions, and a Lucent 360 Photoreactor to facilitate the development of fluorescent pH and Cl# probes. This requested spectroscopic and analytical instrumentation will inform on the design of future electrocatalysts that will be more efficient and thus require reduced power requirements for O2 generation and CO2 disposal on the fly in the undersea environment.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Mar 15, 2024
- Source ID
- N000142412248
Entities
People
- Daniel G. Nocera
Organizations
- Office of Naval Research
- President and Fellows of Harvard College
- United States Navy