posted on 2024-01-04, 02:29authored byFuping Pan, Lingzhe Fang, Boyang Li, Xiaoxuan Yang, Thomas O’Carroll, Haoyang Li, Tao Li, Guofeng Wang, Kai-Jie Chen, Gang Wu
Cu-based catalysts hold promise for electrifying CO2 to produce methane, an extensively used fuel. However, the
activity
and selectivity remain insufficient due to the lack of catalyst design
principles to steer complex CO2 reduction pathways. Herein,
we develop a concept to design carbon-supported Cu catalysts by regulating
Cu active sites’ atomic-scale structures and engineering the
carbon support’s mesoscale architecture. This aims to provide
a favorable local reaction microenvironment for a selective CO2 reduction pathway to methane. In situ X-ray absorption and
Raman spectroscopy analyses reveal the dynamic reconstruction of nitrogen
and hydroxyl-immobilized Cu3 (N,OH-Cu3) clusters
derived from atomically dispersed Cu–N3 sites under
realistic CO2 reduction conditions. The N,OH-Cu3 sites possess moderate *CO adsorption affinity and a low barrier
for *CO hydrogenation, enabling intrinsically selective CO2-to-CH4 reduction compared to the C–C coupling
with a high energy barrier. Importantly, a block copolymer-derived
carbon fiber support with interconnected mesopores is constructed.
The unique long-range mesochannels offer an H2O-deficient
microenvironment and prolong the transport path for the CO intermediate,
which could suppress the hydrogen evolution reaction and favor deep
CO2 reduction toward methane formation. Thus, the newly
developed catalyst consisting of in situ constructed N,OH-Cu3 active sites embedded into bicontinuous carbon mesochannels achieved
an unprecedented Faradaic efficiency of 74.2% for the CO2 reduction to methane at an industry-level current density of 300
mA cm–2. This work explores effective concepts for
steering desirable reaction pathways in complex interfacial catalytic
systems via modulating active site structures at the atomic level
and engineering pore architectures of supports on the mesoscale to
create favorable microenvironments.