Strained Zero‐Valent Iron for Highly Efficient Heavy Metal Removal

Microscale zero‐valent iron is one of the most important multifunctional environmental remediation materials, yet its passivated iron oxide shell hampers the transportation of inherent electrons. Herein, the authors exert tensile strain onto mZVI by interstitial boron doping that destabilizes lattice FeFe interactions, thereby liberating the electrons trapped in the iron reservoir. Tensile strain also upshifts the equilibrated Fermi level at the iron/iron oxide Ohmic heterojunction, thus populating the oxide shell with abundant electrons for robust heavy metal sequestration. Strained‐mZVI exhibits a 62 times faster Cr(VI) removal rate than its unstrained counterpart and can successfully treat industrial wastewater such as landfill leachate, electroplating, and chromium effluents. The excellent property and exceedingly low cost ($2000 ton−1) of strained‐mZVI results in its great potential to remediate heavy metal‐contaminated water and soil. Strain effect endows an outstanding balance between reactivity and costs in zero‐valent iron for efficient heavy metal control.