Issue 40, 2023

Advances in photo-assisted seawater splitting promoted by green iron oxide-carbon nitride photoelectrocatalysts

Abstract

Solar-driven seawater electrolysis for hydrogen fuel production holds an outstanding potential towards the development of a carbon-neutral and sustainable energy infrastructure, but the development of green, efficient and stable photoelectrocatalysts selectively promoting oxygen evolution remains a formidable challenge. Motivated by this issue, in this work we propose a tailored combination of two economically viable materials, α-Fe2O3 and graphitic carbon nitride (gCN), to fabricate promising anodes – eventually decorated with cobalt phosphate (CoPi) particles – for alkaline seawater photosplitting. The target systems were fabricated via an original multi-step route, involving the plasma-enhanced chemical vapor deposition of iron(III) oxide on conducting glasses, the introduction of gCN in very small amounts by a rapid and facile electrophoretic process, and final annealing in air. A comprehensive characterization revealed the successful fabrication of composites featuring a tailored surface defectivity, a controlled nano-organization, and a close Fe2O3/gCN interfacial contact. After decoration with CoPi, the best performances corresponded to a Tafel slope of ≈100 mV dec−1 and overpotential values enabling us to rule out the competitive hypochlorite formation. In addition, photocurrent densities at 1.23 V vs. RHE showed a nearly 7-fold increase upon Fe2O3 functionalization with both gCN and CoPi. These amenable results, directly dependent on the electronic interplay at Fe2O3/gCN heterojunctions and on CoPi beneficial effects, are accompanied by a remarkable long-term stability, and may open up attractive avenues for clean energy production using natural resources.

Graphical abstract: Advances in photo-assisted seawater splitting promoted by green iron oxide-carbon nitride photoelectrocatalysts

Supplementary files

Article information

Article type
Paper
Submitted
24 jul 2023
Accepted
14 sep 2023
First published
14 sep 2023
This article is Open Access
Creative Commons BY-NC license

J. Mater. Chem. A, 2023,11, 21595-21609

Advances in photo-assisted seawater splitting promoted by green iron oxide-carbon nitride photoelectrocatalysts

M. Benedet, G. A. Rizzi, O. I. Lebedev, V. Roddatis, C. Sada, J. Wree, A. Devi, C. Maccato, A. Gasparotto and D. Barreca, J. Mater. Chem. A, 2023, 11, 21595 DOI: 10.1039/D3TA04363K

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