High-loading As single-atom catalysts harvested from wastewater towards efficient and sustainable oxygen reduction

Arsenic (As) is a common element in groundwater contamination with similar chemical properties to nitrogen, exhibiting potential activity towards oxygen reduction reaction (ORR). However, the practical application of recovering arsenic-containing contaminants for ORR faces the formidable challenge of a trade-off between high activity and stability. Herein, we first report universal strategies to synthesize high-loading (up to 13.78 wt%) non-metal monoatoms on carbon and prepare As monoatomic catalysts as a demonstration. The dispersed zinc ions chelated by alpha-d-glucose significantly increase the loading of As monoatoms. Moreover, topological defects constructed by zinc evaporation enhance the intrinsic activity of adjacent As. The catalyst exhibits a much better half-wave potential (0.901 V) than 20% Pt/C (0.856 V). Re-calcination is further proposed to overcome the poor oxidation resistance of catalysts with abundant carbon defects. The catalyst treated by re-calcination demonstrates unprecedented stability, with only 9.86% deterioration in current density after 590 hours of operation in the fuel cell, outperforming the most advanced carbon-based catalysts. Our discoveries facilitate the practical application of high-loading, high-activity and high-stability non-metal catalysts originating from pollutants. We first report universal strategies to synthesize high-loading (up to 13.78 wt%) non-metal monoatoms on carbon. Re-calcination is further proposed to overcome the poor oxidation resistance of catalysts with abundant carbon defects.

Automated summary

This study reports universal strategies for synthesizing high-loading non-metal monoatom catalysts and demonstrates the synthesis of As monoatomic catalysts. The use of alpha-D-glucose chelated zinc ions significantly increases the loading of As monoatoms, while topological defects constructed by zinc evaporation enhance the intrinsic activity of adjacent As. Recalcination is proposed to improve the oxidation resistance of catalysts with abundant carbon defects.