Conversion of CO2 to chemical feedstocks over bismuth nanosheets in situ grown on nitrogen-doped carbon

Abstract

The conversion of CO₂ to value-added chemicals represents an attractive approach for CO₂ utilization. Formate and methanol are sustainably valuable fuels and chemical feedstocks. However, the CO₂ reduction reaction (CO₂RR) suffers from unsatisfactory activity, low faradaic efficiency (FE) and inadequate durability. In this study, ultrathin bismuth nanosheets (NSs) and Bi NSs grown on nitrogen-doped ordered mesoporous carbon (OMC-N) are prepared from in situ transformation of atomic-thick Bi₂O₂Se and Bi₂O₂Se/OMC-N. Bi NSs enable efficient formate production with a large current density (51 mA cm⁻² at −1.0 V_RHE) and excellent selectivity (FE ≈ 90%). Interestingly, Bi NSs/OMC-N catalyzes the conversion of CO₂ to formate and methanol simultaneously with maximum FE_formate (70%) and FE_methanol (67%), and long-term stability (35 h). The composition produces 9.15 and 8.00 μmol cm⁻² h⁻¹ for formate and methanol at −0.67 V_RHE, respectively, and methyl formate could be further prepared from the above products. Moreover, the generated Bi NSs achieve 288 mA cm⁻² at −0.61 V_RHE within a flow cell. Theoretical studies reveal that the activity for methanol is rationalized as the outcome of abundant pyridinic-N sites that stabilize the *COOH intermediate. Our study unveils the potential of hierarchical Bi NSs/OMC-N for an efficient and stable CO₂RR to produce chemical feedstocks.