Operando Formation of Self‐Adaptive Catalysts From Wastewater During Hydrogen Evolution Reaction

ABSTRACT Untreated metallurgical wastewater contains various heavy metal ions M x+ (such as Fe 3+ , Co 2+ , Ni 2+ , and Cu 2+ ). Traditional treatment methods usually involve energy‐intensive separation and resynthesis steps. To address this issue, this work proposes the in situ reconstruction of metal ions from the wastewater into self‐adaptive catalysts (MO y H z /VNO x ) during the hydrogen evolution reaction (HER), which actively adapt to the HER environment. After reconstruction, trace residual metal species also modulate catalytic activity. Among the obtained catalysts, β‐Co(OH) 2 /VNO x shows the best HER activity, with Co─O─V as the active center. Theoretical calculations reveal that β‐Co(OH) 2 tunes the electronic structure of VNO x , weakening H * adsorption and lowering the H 2 O dissociation barrier. Thus, β‐Co(OH) 2 /VNO x reduces the overpotential ( η ) at −10 mA cm −2 by 268 and 301 mV compared to β‐Co(OH) 2 and VNO x , respectively. This work offers an eco‐friendly strategy for simultaneous metal recovery and hydrogen production, with potential applications in energy transformation and environmental cleanup.