Dual single-cobalt atom-based carbon electrocatalysts for efficient CO2-to-syngas conversion with industrial current densities.

[Display omitted] • Single-atom Co based dual-site catalyst is constructed. • N- and CoN 3 -anchored CoPc have distinct active for CO 2 RR and HER. • Distinct interaction of CoPc and anchored sites govern their catalytical ability. • Syngas with ideal H 2 /CO ratio is produced with industrial current density. • Syngas also produced by a Zn−CO 2 battery at high discharging current density. Dual single-cobalt atom-based catalysts were synthesized using CoN 3 sites and N dopants co-decorated hierarchically porous carbon (HPC-Co) as the matrix to immobilize cobalt phthalocyanine (CoPc). CoPc interacts with N dopants and CoN 3 , forming N-CoPc and CoN 3 -CoPc sites via π–π and Co-Co interactions. HPC-Co/CoPc (5:1) produced syngas at industrial current densities (> 200 and 880 mA cm−2 for the H-type and flow cell, respectively). Rechargeable Zn-CO 2 batteries based on this catalyst had current densities of 7 and 10 mA cm−2 at ideal H 2 /CO ratios of 2 and 3, respectively. The efficient production of syngas is attributed to synergistic catalysis between N-CoPc (for CO 2 reduction) and CoN 3 -CoPc (for hydrogen evolution). This work presents a versatile strategy for the synthesis of dual single-atom-based carbon electrocatalysts for efficient conversion of CO 2 to syngas. This strategy is superior to conventional high-temperature pyrolysis that is difficult to control the atomic dispersion of distinct metal sites. [ABSTRACT FROM AUTHOR]