Nitrogen-doped porous carbon nanosheets as a robust catalyst for tunable CO2 electroreduction to syngas

Abstract

High-efficiency electrochemical CO₂-to-syngas conversion with a tunable H₂/CO ratio is a desirable strategy for achieving energy storage and is subsequently a carbon neutral process. However, the customisation of the H₂/CO ratio is still a major challenge for the development of CO₂ electroreduction. To address this issue, a simple impregnation–calcination strategy was developed to prepare 2D porous nitrogen-doped carbon nanosheets (NCN) as metal-free electrocatalysts. The as-prepared NCN-6 achieves a 70% faradaic efficiency for CO production and excellent durability over 25 h at a low potential of −0.6 V vs. a reversible hydrogen electrode (RHE). Importantly, a wide H₂/CO ratio ranging from 0.43 to 3.17 was realised, thereby enabling a downstream Fischer–Tropsch process for gas-to-liquid fuel conversion. The enhanced electrocatalytic performance can be attributed to the synergistic effect of well-developed porosity and the effective pyridine nitrogen active sites in the 2D porous NCN. This work has great potential for sustainable manufacturing of high value-added downstream products from the syngas industry.