Phase and structure modulating of bimetallic Cu/In nanoparticles realizes efficient electrosynthesis of syngas with wide CO/H₂ ratios

Syngas (CO + H₂) is the incredibly important feedstock for producing synthetic fuels and various value-added chemicals. CO₂ electrochemical reduction to syngas is an environmental-friendly and sustainable approach, but still challenging to produce tunable syngas with a wide ratio of CO/H₂. Herein, by modulating the structure and phase, we have successfully obtained a series of copper–indium (Cu-In) catalysts, which are efficient for producing syngas with tunable CO/H₂ ratios. A series of CuIn bimetallic catalysts with different structures from hollow sphere to two-layer hollow sphere and different phases from CuO to Cu₂O are developed. We find that the CO and H₂ are the only gaseous products, in which the CO/H₂ ratios can be readily tuned from 1.2 ± 0.1 to 9.0 ± 1.5 by simply controlling the thermal annealing temperature. It also exhibits high durability during a 10-h test. The unique performance is attributed to the modulated In enrichment on the Cu surfaces during the CO₂ reduction reaction, which causes the differences in binding energies for key reaction intermediates, thus resulting in the tunable composition of syngas. The present work emphasizes a simple yet efficient phase and structure modulating strategy for designing potential electrocatalysts for producing syngas with widely tunable CO/H₂ ratios.