Interface-hydroxyl enabling methanol steam reforming toward CO-free hydrogen production over inverse ZrO₂/Cu catalyst

Methanol steam reforming (MSR), as an ideal on-site hydrogen production process, is urgently calling for a groundbreaking catalyst with ultralow or even no CO formation. Herein, we report a promising inverse ZrO₂/Cu catalyst system obtained by oxalate sol-gel co-precipitation and subsequent calcination/H₂-reduction treatment, boosting the MSR process toward CO-free hydrogen production. The preferred ZrO₂-0.1/Cu (Zr/Cu molar ratio of 0.1) achieves a high H₂ productivity of 190 mmol_H2 g_cat⁻¹ h⁻¹ with undetectable CO production at 200 °C for a feed of CH₃OH/H₂O (1/1, mol/mol), while showing no deactivation throughout 200-h test by taking advantage of high sintering resistance of the inverse structure. As experimentally and theoretically unveiled, the specific ZrO(OH)-(Cu⁺/Cu) interfacial structure is formed during the reaction, offering highly reactive interfacial -OH to convert HCHO* (formed on Cu⁺/Cu sites from methanol; decomposable to CO/H₂) into H₂ and CO₂ via HCOOH* intermediate. These findings will be instrumental to tailor more-advanced MSR catalysts.