Sn‐doped CeO 2 Nanorods as High‐Performance Electrocatalysts for CO 2 Reduction to Formate

Favoring Product Desorption by a Tailored Electronic Environment of Oxygen Vacancies in SrTiO3 via Cr Doping for Enhanced and Selective Electrocatalytic CO2 to CO Conversion

The electrochemical CO₂ reduction reaction (ECO₂RR) into value-added products is crucial to address the herculean task of CO₂ mitigation. Several efforts are being made to develop active ECO₂RR catalysts, targeting enhanced CO₂ adsorption and activation. A rational design of ECO₂RR catalysts with a facile product desorption step is seldom reported. Herein, ensuing the Sabatier principle, we report a strategy for an enhanced ECO₂RR with a faradaic efficiency of 85% for CO production by targeting the product desorption step. The energy barrier for product desorption was lowered via a tailored electronic environment of oxygen vacancies (O_vac) in Cr-doped SrTiO₃. The substitutional doping of Cr³⁺ for Ti⁴⁺ into the SrTiO₃ lattice favors the generation of more O_vac and modifies the local electronic environment. Density functional theory analysis evinces the spontaneous dissociation of COOH^# intermediates over O_vac and lower CO intermediate binding on O_vac reducing the energy demand for CO release due to Cr doping.

Enhanced electrocatalytic reduction of CO2 to formate via doping Ce in Bi2O3 nanosheets

Formate is considered as the most economically viable product of the prevalent electrochemical CO₂ reduction (ECR) products. However, most of the catalysts for ECR to formate in aqueous solution often suffer from low activity and limited selectivity. Herein, we report a novel Ce-doped Bi₂O₃ nanosheet (NS) electrocatalyst by a facile solvothermal method for highly efficient ECR to formate. The 5.04% Ce-doped Bi₂O₃ NSs exhibited a current density of 37.4 mA cm^-2 for the production of formate with a high formate faradaic efficiency (FE) of 95.8% at -1.12 V. The formate FE was stably maintained at about 90% in a wide potential range from -0.82 to -1.22 V. More importantly, density functional theory (DFT) calculations revealed that Ce doping can lead to a significant synergistic effect, which promotes the formation and the adsorption of the OCHO* intermediate for ECR, while significantly inhibiting the hydrogen evolution reaction via depressing the formation of *H, thus helping achieve high current density and FE. This work provides an effective and promising strategy to develop efficient electrocatalysts with heteroatom doping and new insights for boosting ECR into formate.