Work

Scalable Ir-Doped NiFe2O4/TiO2 Heterojunction Anode for Decentralized Saline Wastewater Treatment and H2 Production

Year: 2024

Type: article

Abstract: Wastewater electrolysis cells (WECs) for decentralized wastewater treatment/reuse coupled with H2 production can reduce the carbon footprint associated with transportation of water, waste, and energy carrier. This study reports Ir-doped NiFe2O4 (NFI, ~ 5 at% Ir) spinel layer with TiO2 overlayer (NFI/TiO2), as a scalable heterojunction anode for direct electrolysis of wastewater with circumneutral pH in a single-compartment cell. In dilute (0.1 M) NaCl solutions, the NFI/TiO2 marks superior activity and selectivity for chlorine evolution reaction, outperforming the benchmark IrO2. Robust operation in near-neutral pH was confirmed. Electroanalyses including operando X-ray absorption spectroscopy unveiled crucial roles of TiO2 which serves both as the primary site for Cl− chemisorption and a protective layer for NFI as an ohmic contact. Galvanostatic electrolysis of NH4 +-laden synthetic wastewater demonstrated that NFI/TiO2 not only achieves quasi-stoichiometric NH4 +-to-N2 conversion, but also enhances H2 generation efficiency with minimal competing reactions such as reduction of dissolved oxygen and reactive chlorine. The scaled-up WEC with NFI/TiO2 was demonstrated for electrolysis of toilet wastewater.

Source: Nano-Micro Letters

DOI: 10.1007/s40820-024-01542-x

Authors: Sukhwa Hong, Jiseon Kim, Jaebeom Park, Sunmi Im, Michael R. Hoffmann, Kangwoo Cho

Institutions: Pohang University of Science and Technology, California Institute of Technology, Yonsei University

Language: English

Topic: Electrocatalysts for Energy Conversion

Subfield: Renewable Energy, Sustainability and the Environment

Field: Energy

Domain: Physical Sciences

SDGs: Affordable and clean energy, Clean water and sanitation, Responsible consumption and production

Open Access status: gold

Estimated APC paid: $1,590