Three-dimensional N-doped carbon nanosheets loaded with heterostructured Ni/Ni 3 ZnC 0.7 nanoparticles for selective and efficient CO 2 reduction.

Electrocatalytic CO 2 reduction (CO 2 RR) has emerged as a promising approach for converting CO 2 into valuable chemicals and fuels to achieve a sustainable carbon cycle. However, the development of efficient electrocatalysts with high current densities and superior product selectivity remains a significant challenge. In this study, we present the synthesis of a porous nitrogen-doped carbon nanosheet loaded with heterostructured Ni/Ni 3 ZnC 0.7 nanoparticles through a facile hydrothermal-calcination method (Ni/Ni 3 ZnC 0.7 -NC). Remarkably, the Ni/Ni 3 ZnC 0.7 -NC catalyst exhibits outstanding performance towards CO 2 RR in an H-cell, demonstrating a high CO faradaic efficiency of 92.47% and a current density ( j CO ) of 15.77 mA cm -2 at 0.87 V vs. RHE. To further explore its potential industrial applications, we constructed a flow cell and a rechargeable Zn-CO 2 flow cell utilizing the Ni/Ni 3 ZnC 0.7 -NC catalyst as the cathode. Impressively, not only does the Ni/Ni 3 ZnC 0.7 -NC catalyst achieve an industrial high current density of 254 mA cm -2 at a voltage of -1.19 V vs. RHE in the flow cell, but it also exhibits a maximum power density of 4.2 mW cm -2 at 22 mA cm -2 in the Zn-CO 2 flow cell, while maintaining excellent rechargeability. Density functional theory (DFT) calculations indicate that Ni/Ni 3 ZnC 0.7 -NC possesses more spontaneous reaction pathways for CO 2 reduction to CO, owing to its heterogeneous structure in contrast to Ni 3 ZnC 0.7 -NC and Ni-NC. Consequently, Ni/Ni 3 ZnC 0.7 -NC demonstrates accelerated CO 2 RR reaction kinetics, resulting in improved catalytic activity and selectivity for CO 2 RR.