Hollow Hierarchical Cu 2 O-Derived Electrocatalysts Steering CO 2 Reduction to Multi-Carbon Chemicals at Low Overpotentials.

The electrochemical reduction of carbon dioxide into multi-carbon products (C 2+ ) using renewably generated electricity provides a promising pathway for energy and environmental sustainability. Various oxide-derived copper (OD-Cu) catalysts have been showcased, but still require high overpotential to drive C 2+ production owing to sluggish carbon-carbon bond formation and low CO intermediate (*CO) coverage. Here, the dilemma is circumvented by elaborately devising the OD-Cu morphology. First, computational studies propose a hollow and hierarchical OD-Cu microstructure that can generate a core-shell microenvironment to inhibit CO evolution and accelerate *CO dimerization via intermediate confinement and electric field enhancement, thereby boosting C 2+ generation. Experimentally, the designed nanoarchitectures are synthesized through a heteroseed-induced approach followed by electrochemical activation. In situ spectroscopic studies further elaborate correlation between *CO dimerization and designed architectures. Remarkably, the hierarchical OD-Cu manifests morphology-dependent selectivity of CO 2 reduction, giving a C 2+ Faradaic efficiency of 75.6% at a considerably positive potential of -0.55 V versus reversible hydrogen electrode.