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

Abstract

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 mmolH2 gcat−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.