Reverse hydrogen spillover accelerates electrocatalytic nitrate reduction to ammonia on Ru/WO<sub>3-x</sub> in acidic media.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 41698935.
- Also identified by DOI 10.1038/s41467-026-69335-x and PMC identifier 13022183.
- Licence recorded as CC BY-NC-ND.
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Abstract
The electrocatalytic nitrate reduction reaction (NO<sub>3</sub><sup>-</sup>RR) offers a promising route to sustainable ammonia synthesis, potentially replacing the energy-intensive Haber-Bosch process. While often studied in neutral or alkaline media, NO<sub>3</sub><sup>-</sup>RR in acidic conditions is particularly relevant due to widespread industrial acidic nitrate wastewater, yet it remains challenging due to corrosion and dominant hydrogen evolution. To address this, we designed a corrosion-resistant Ru/WO<sub>3-x</sub> heterostructure that spatially separates proton and nitrate adsorption sites. Here, we show that a reverse hydrogen spillover effect, where the WO<sub>3-x</sub> support stores and transports protons to surface Ru active sites, dramatically enhances hydrogenation kinetics and suppresses parasitic hydrogen evolution. This catalyst achieves an ammonia Faradaic efficiency of 94.09% at a high current density of 500 mA cm<sup>-2</sup> and a working potential of 0.026 V vs. reversible hydrogen electrode. Furthermore, we demonstrate a sulfide-nitrate "batterolyzer" with a discharge power density of 43.4 mW cm<sup>-2</sup>. This work reveals an effective proton-management strategy for efficient acidic NO<sub>3</sub><sup>-</sup>RR, advancing its potential for coupled ammonia synthesis and wastewater treatment.