Cu2O/lanthanide hydroxide boosting electrocatalytic CO2 reduction via stabilizing Cu(I)

As important catalysts for C–C coupling, copper-based materials have great potential for electrocatalytic reduction of CO 2 to C 2+ products. In this work, Cu 2 O catalysts modified with different lanthanide hydroxides were successfully synthesized and used for CO 2 electroreduction. The results showed that compared with Cu 2 O/Gd(OH) 3 and Cu 2 O/Yb(OH) 3 catalysts, Cu 2 O/La(OH) 3 exhibited the highest electrocatalytic performance for CO 2 reduction. This catalyst was able to maintain a high Faraday efficiency for C 2+ products ( \({\rm FE}_{{\rm C}_{2+}}\) ) of about 60% within the current density range of 400–800 mA cm −2 . The highest \({\rm FE}_{{\rm C}_{2+}}\) reached 66% at 600 mA cm −2 and the partial current density for C 2+ products reached a maximum of 488 mA cm −2 . Meanwhile, the catalyst could run stably for 40 h with a remained \({\rm FE}_{{\rm C}_{2+}}\) of about 60%. Multiple characterizations reveal that the introduction of La(OH) 3 promotes the formation of *CO intermediates, and also helps to stabilize the Cu(I) species in Cu 2 O under cathodic potentials, thus facilitating the C–C coupling for C 2+ production. This work provides a new strategy to enhance the C 2+ production via stabilizing Cu(I).