Integration of MnO 2 Nanosheets with Pd Nanoparticles for Efficient CO 2 Electroreduction to Methanol in Membrane Electrode Assembly Electrolyzers.

It remains a challenge to design a catalyst with high selectivity at a large current density toward CO 2 electrocatalytic reduction (CO 2 ER) to a single C 1 liquid product of methanol. Here, we report the design of a catalyst by integrating MnO 2 nanosheets with Pd nanoparticles to address this challenge, which can be implemented in membrane electrode assembly (MEA) electrolyzers for the conversion of CO 2 ER to methanol. Such a strategy modifies the electronic structure of the catalyst and provides additional active sites, favoring the formation of key reaction intermediates and their successive evolution into methanol. The optimal catalyst delivers a Faradaic efficiency of 77.6 ± 1.3% and a partial current density of 250.8 ± 4.3 mA cm -2 for methanol during CO 2 ER in an MEA electrolyzer by coupling anodic oxygen evolution reaction with a full-cell energy efficiency achieving 29.1 ± 1.2% at 3.2 V. This work opens a new avenue to the control of C 1 intermediates for CO 2 ER to methanol with high selectivity and activity in an MEA electrolyzer.