We unprecedentedly report spatially separated CoNx nanodots on carbon nanotubes (CNTs) via a facile formamide condensation reaction. To our knowledge, CoNx-CNTs outperform the activities of current catalysts in peroxymonosulfate activation. CoNx-CNT-oriented radical-free degradation of contaminants shows robust anti-interference capacity toward environmental conditions. Our work will stimulate general interest in designing cost-effective and versatile quantum-/atom-sized catalysts with fully exposed active sites for water purification and beyond.