An Environment‐Friendly Strategy for One‐Step Turning Cr(VI) Contaminant into a Cr‐Loaded Catalyst for CO₂ Utilization

Abstract A one‐step strategy to obtain a high‐performance catalyst from Cr(VI)‐containing wastewater by the photoreduction process is described. ZrO₂ is employed as a wide bandgap and high conduction‐band photocatalyst to reduce, capture, and immobilize Cr(VI) ions under UV light irradiation. The byproduct of this step is used as a catalyst for the CO₂ reverse water‐gas shift (RWGS) reaction. The total Cr content in water decreases to 0.0413 mg L⁻¹ in 3 h, fulfilling the strictest wastewater standard. The soluble Cr(VI) species is converted into Cr(0) and Cr(III), and fixed on the ZrO₂ surface to form Cr@ZrO₂ as a byproduct with highly dispersed Cr species. Using this byproduct as a catalyst for the RWGS reaction results in almost thermal equilibrium conversion under 500 °C with 100% CO selectivity. This environment‐friendly and economic strategy is very promising for controlling heavy metal pollution and comprehensive CO₂ utilization.