A topological chemical transition strategy of bismuth-based materials for high-efficiency electrocatalytic carbon dioxide conversion to formate

Abstract

The electrochemical reduction of carbon dioxide (ERCO₂) to formate with high selectivity has been considered a promising strategy to overcome the energy and environmental crises. Bi-based materials present good application prospects, but the development of a new class of electrocatalysts with high performance remains a challenge. Herein, a novel topological chemical transition strategy is developed to rationally design highly active Bi-based materials, which are a new representative of Bi-based electrocatalysts for ERCO₂. Bismuth oxysulfate (Bi₂O₂SO₄) is prepared by a simple topological transition from the Bi₂S₃ precursor in air, which can further topologically transform into the metal Bi by a fast reduction treatment of NaBH₄ solution. This kind of Bi₂O₂SO₄ exhibits superior catalytic performance for ERCO₂. The maximum Faraday efficiency (FE) of HCOO⁻ is up to 97% at −0.9 V vs. RHE in an H-type cell. A high FE > 90% in a wide potential range of −0.5 to −1.2 V and a large current density of 319 mA cm⁻² at −0.8 V can further be realized in a flow cell. The post-characterization studies and density functional theory (DFT) calculations confirm that the Bi₂O₂SO₄ derived Bi catalyst has an optimal (104) plane to realize the optimized free energies of OCHO* and H* reaction intermediates, leading to superior catalytic activity over the NaBH₄ derived Bi sample. Our work put forward a promising strategy to exploit advanced electrocatalysts for electrolysis.