Plasma-Engineered Diamond-like Carbon/NiFe Composite Films as Stable and Multifunctional Protection Layers for Photoelectrochemical Cells
At a Glance
Section titled āAt a Glanceā| Metadata | Details |
|---|---|
| Publication Date | 2025-07-11 |
| Journal | ECS Meeting Abstracts |
| Authors | Yamini Kumaran, Iulian Gherasoiu, Haralabos Efstathiadis |
Abstract
Section titled āAbstractāNanostructured diamond-like carbon (DLC) films integrated with NiFe layered double hydroxide (LDH) were developed as protection layers for semiconductor photoelectrochemical water splitting. A systematic study of plasma-enhanced chemical vapor deposition parameters including CH 4 /Ar ratio, RF power, substrate temperature and vacuum annealing enabled precise control of sp 3 /sp 2 hybridization and optical bandgap (4.8-5.2 eV) of the DLC films. Raman spectroscopy and X-ray photoelectron spectroscopy reveal optimal deposition conditions at 300Ā°C yielded maximum sp 3 content (~75%). The nanostructured films were etched via reactive ion etching using O 2 plasma, with the etch rate and feature size controlled through gas ratio, RF bias, and chamber pressure. Optimization of these parameters produced uniform high-aspect-ratio structures with 50-200 nm spacing and depths up to 500 nm. NiFe LDH is selectively electrodeposited within etched regions, with the deposition potential and time tuned to achieve optimal catalyst loading. The nanostructured DLC/NiFe composite demonstrated excellent chemical stability across pH 1-14 and significantly reduced the overpotential for water oxidation. Surface analysis by SEM confirmed uniform NiFe distribution while maintaining film continuity. Impedance measurements showed enhanced charge transport through the composite structure. Electrochemical characterization was conducted to understand the onset potential and current densities achieved in alkaline media. The dual-function protective and catalytic coating enabled the stable operation of underlying photoelectrodes while facilitating efficient water oxidation kinetics. This work demonstrated a promising strategy for integrating protection layers with electrocatalysts for photoelectrochemical water-splitting systems.